Publications by authors named "Mauro Iori"

34 Publications

Use of knowledge based DVH predictions to enhance automated re-planning strategies in head and neck adaptive radiotherapy.

Phys Med Biol 2021 Jun 23;66(13). Epub 2021 Jun 23.

School of Engineering, Cardiff University, Cardiff, United Kingdom.

This study aimed to investigate if a commercial, knowledge-based tool for radiotherapy planning could be used to estimate the amount of sparing in organs at risk (OARs) in the re-planning strategy for adaptive radiotherapy (ART). Eighty head and neck (HN) VMAT Pareto plans from our institute's database were used to train a knowledge-based planning (KBP) model. An evaluation set of another 20 HN patients was randomly selected. For each patient in the evaluation set, the planning computed tomography (CT) and 2 sets of on-board cone-beam CT, corresponding to the middle and second half of the radiotherapy treatment course, were extracted. The original plan was re-calculated on a daily deformed CT (delivered dose-volume histogram (DVH)) and compared with the KBP DVH predictions and with the final KBP DVH after optimisation of the plan, which was performed on the same image sets. To evaluate the feasibility of this method, the range of KBP DVH uncertainties was compared with the gains obtained from re-planning. DVH differences and receiver operating characteristic (ROC) curve analysis were used for this purpose. On average, final KBP uncertainties were smaller than the gain in re-planning. Statistical tests confirmed significant differences between the two groups. ROC analysis showed KBP performance in terms of area under the curve values higher than 0.7, which confirmed a good accuracy in predicted values. Overall, for 48% of cases, KBP predicted a desirable outcome from re-planning, and the final dose confirmed an effective gain in 47% of cases. We have established a systematic workflow to identify effective OAR sparing in re-planning based on KBP predictions that can be implemented in an on-line, ART process.
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http://dx.doi.org/10.1088/1361-6560/ac08b0DOI Listing
June 2021

How direct measurements on worker eyes with Scheimpflug camera can affect lens dose conversion coefficients in interventional radiology.

J Radiol Prot 2021 Apr 7. Epub 2021 Apr 7.

Industrial Engineering - Montecuccolino Laboratory, University of Bologna, Via dei Colli 16, 40136 Bologna, Italy, Bologna, BO, 40136, ITALY.

The Directive 2013/59/Euratom established a reduction of the occupational exposure limits to the lens. Since it is become crucial to estimate the lens absorbed dose, the individual variability of exposed worker's ocular conformations with respect to the data estimated with their personal dosimetry has been studied. The anterior eye conformation of 45 exposed workers was acquired with Scheimpflug imaging and classified according to eye vision conditions (emmetropia, myopia or hypermetropia). Three eye models were computed, with two lens reconstructions, and implemented in an interventional radiology scenario by using Monte Carlo (MC) code. The models were dosimetrically analysed simulating setup A, a theoretical monoenergetic and isotropic photon's source (10-150 keV) and setup B, a more realistic interventional conditions with an angiographic X-ray unit (50, 75, 100 kV-peak). Scheimpflug imaging provided an average anterior chamber depth of (6.4 ± 0.5) mm and a lens depth of (3.9 ± 0.3) mm, together with a reconstructed equatorial lens length of (7.1 - 10.1) mm. Using this data for model's reconstruction, the dose conversion coefficients (DCs) for all ocular structures were simulated. Regardless of the eye model used, DCs show a similar trend with radiation energy which highlights, for the same energy and setup used, no significant dependence on ocular morphology and worker's visual conditions. The maximum difference obtained does not exceed 1% for all eye models or structures analysed. Therefore, the individual variabilities of worker ocular anatomy do not require any additional correction compared to the personal dosimetry data measured with a dedicated lens dosimeter. To estimate the absorbed dose to the other eye structures, it is essential instead to know the spectrum of the source that has generated the irradiation since there are differences considering monoenergetic sources or more realistic angiographic units.
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http://dx.doi.org/10.1088/1361-6498/abf56fDOI Listing
April 2021

EPID-based 3D dosimetry for pre-treatment FFF VMAT stereotactic body radiotherapy plan verification using dosimetry Check.

Phys Med 2021 Jan 20;81:227-236. Epub 2021 Jan 20.

Medical Physics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy; School of Engineering, Cardiff University, Cardiff, UK.

Purpose: The software Dosimetry Check (DC) reconstructs the 3D dose distribution on CT images data set by using EPID measured signal. This study aimed to evaluate DC for stereotactic body radiotherapy (SBRT) with unflattened photon beams (FFF) for dosimetric independent plan verification in pre-treatment modality.

Methods: DC v.4.1 was configured for Varian TrueBeam STx FFF beams equipped with EPID aS-1200. The DC FFF models were tested using arc open fields (from 1×1 cm to 15×15 cm) and VMAT (Volumetric Modulated Arc Therapy) SBRT plans on phantom and patient CTs. DC dose distributions (D) were compared with that calculated by Eclipse with Acuros XB algorithm (D) and one measured by Octavius 1000 SRS detector (D). All differences were quantified in terms of the local 3D gamma passing rate (%GP), DVH and point dose differences.

Results: DC was configured for FFF VMAT using an appropriate correction procedure. %GP (mean±standard deviation) of D-D was 96.3±2.7% for open fields whereas it was 90.1±5.9% for plans on homogeneous phantom CT. However, average %GP of D-D was 95.0±4.1 for treatments on patient CT. The fraction of plans passing the %GP DQA tolerance level [10% (50%) of maximum dose threshold] were 20/20 (14/20) and 18/20 (16/20) for OCT on phantom CT and DC on patient CT, respectively.

Conclusions: DC characterization for FFF beams was performed. For stereotactic VMAT plan verifications DC showed good agreement with TPS whereas underlined discrepancies with Octavius in the high dose regions. A customized tolerance level is required for EPID-based VMAT FFF pre-treatment verification when DC system is applied.
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http://dx.doi.org/10.1016/j.ejmp.2020.12.014DOI Listing
January 2021

DNA damage in lens epithelial cells exposed to occupationally-relevant X-ray doses and role in cataract formation.

Sci Rep 2020 12 10;10(1):21693. Epub 2020 Dec 10.

Department of Medical Physics, St. Orsola-Malpighi University Hospital, Bologna, Italy.

The current framework of radiological protection of occupational exposed medical workers reduced the eye-lens equivalent dose limit from 150 to 20 mSv per year requiring an accurate dosimetric evaluation and an increase understanding of radiation induced effects on Lens cells considering the typical scenario of occupational exposed medical operators. Indeed, it is widely accepted that genomic damage of Lens epithelial cells (LEC) is a key mechanism of cataractogenesis. However, the relationship between apoptosis and cataractogenesis is still controversial. In this study biological and physical data are combined to improve the understanding of radiation induced effects on LEC. To characterize the occupational exposure of medical workers during angiographic procedures an INNOVA 4100 (General Electric Healthcare) equipment was used (scenario A). Additional experiments were conducted using a research tube (scenario B). For both scenarios, the frequencies of binucleated cells, micronuclei, p21-positive cells were assessed with different doses and dose rates. A Monte-Carlo study was conducted using a model for the photon generation with the X-ray tubes and with the Petri dishes considering the two different scenarios (A and B) to reproduce the experimental conditions and validate the irradiation setups to the cells. The simulation results have been tallied using the Monte Carlo code MCNP6. The spectral characteristics of the different X-ray beams have been estimated. All irradiated samples showed frequencies of micronuclei and p21-positive cells higher than the unirradiated controls. Differences in frequencies increased with the delivered dose measured with Gafchromic films XR-RV3. The spectrum incident on eye lens and Petri, as estimated with MCNP6, was in good agreement in the scenario A (confirming the experimental setup), while the mean energy spectrum was higher in the scenario B. Nevertheless, the response of LEC seemed mainly related to the measured absorbed dose. No effects on viability were detected. Our results support the hypothesis that apoptosis is not responsible for cataract induced by low doses of X-ray (i.e. 25 mGy) while the induction of transient p21 may interfere with the disassembly of the nuclear envelop in differentiating LEC, leading to cataract formation. Further studies are needed to better clarify the relationship we suggested between DNA damage, transient p21 induction and the inability of LEC enucleation.
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http://dx.doi.org/10.1038/s41598-020-78383-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7728785PMC
December 2020

Uncertainty analysis of tumour absorbed dose calculations in molecular radiotherapy.

EJNMMI Phys 2020 Oct 12;7(1):63. Epub 2020 Oct 12.

Medical Physics Unit, Azienda Unità Sanitaria Locale di Reggio Emilia - IRCCS, Reggio Emilia, Italy.

Background: Internal dosimetry evaluation consists of a multi-step process ranging from imaging acquisition to absorbed dose calculations. Assessment of uncertainty is complicated and, for that reason, it is commonly ignored in clinical routine. However, it is essential for adequate interpretation of the results. Recently, the EANM published a practical guidance on uncertainty analysis for molecular radiotherapy based on the application of the law of propagation of uncertainty. In this study, we investigated the overall uncertainty on a sample of a patient following the EANM guidelines. The aim of this study was to provide an indication of the typical uncertainties that may be expected from performing dosimetry, to determine parameters that have the greatest effect on the accuracy of calculations and to consider the potential improvements that could be made if these effects were reduced.

Results: Absorbed doses and the relative uncertainties were calculated for a sample of 49 patients and a total of 154 tumours. A wide range of relative absorbed dose uncertainty values was observed (14-102%). Uncertainties associated with each quantity along the absorbed dose calculation chain (i.e. volume, recovery coefficient, calibration factor, activity, time-activity curve fitting, time-integrated activity and absorbed dose) were estimated. An equation was derived to describe the relationship between the uncertainty in the absorbed dose and the volume. The largest source of error was the VOI delineation. By postulating different values of FWHM, the impact of the imaging system spatial resolution on the uncertainties was investigated.

Discussion: To the best of our knowledge, this is the first analysis of uncertainty in molecular radiotherapy based on a cohort of clinical cases. Wide inter-lesion variability of absorbed dose uncertainty was observed. Hence, a proper assessment of the uncertainties associated with the calculations should be considered as a basic scientific standard. A model for a quick estimate of uncertainty without implementing the entire error propagation schema, which may be useful in clinical practice, was presented. Ameliorating spatial resolution may be in future the key factor for accurate absorbed dose assessment.
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http://dx.doi.org/10.1186/s40658-020-00328-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7550507PMC
October 2020

Comparison of different calculation techniques for absorbed dose assessment in patient specific peptide receptor radionuclide therapy.

PLoS One 2020 7;15(8):e0236466. Epub 2020 Aug 7.

Azienda Unità Sanitaria Locale di Reggio Emilia-IRCCS, Medical Physics Unit, Reggio Emilia, Italy.

Aim: The present work concerns the comparison of the performances of three systems for dosimetry in RPT that use different techniques for absorbed dose calculation (organ-level dosimetry, voxel-level dose kernel convolution and Monte Carlo simulations). The aim was to assess the importance of the choice of the most adequate calculation modality, providing recommendations about the choice of the computation tool.

Methods: The performances were evaluated both on phantoms and patients in a multi-level approach. Different phantoms filled with a 177Lu-radioactive solution were used: a homogeneous cylindrical phantom, a phantom with organ-shaped inserts and two cylindrical phantoms with inserts different for shape and volume. A total of 70 patients with NETs treated by PRRT with 177Lu-DOTATOC were retrospectively analysed.

Results: The comparisons were performed mainly between the mean values of the absorbed dose in the regions of interest. A general better agreement was obtained between Dose kernel convolution and Monte Carlo simulations results rather than between either of these two and organ-level dosimetry, both for phantoms and patients. Phantoms measurements also showed the discrepancies mainly depend on the geometry of the inserts (e.g. shape and volume). For patients, differences were more pronounced than phantoms and higher inter/intra patient variability was observed.

Conclusion: This study suggests that voxel-level techniques for dosimetry calculation are potentially more accurate and personalized than organ-level methods. In particular, a voxel-convolution method provides good results in a short time of calculation, while Monte Carlo based computation should be conducted with very fast calculation systems for a possible use in clinics, despite its intrinsic higher accuracy. Attention to the calculation modality is recommended in case of clinical regions of interest with irregular shape and far from spherical geometry, in which Monte Carlo seems to be more accurate than voxel-convolution methods.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0236466PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413508PMC
September 2020

Texture analysis and multiple-instance learning for the classification of malignant lymphomas.

Comput Methods Programs Biomed 2020 Mar 23;185:105153. Epub 2019 Oct 23.

Medical Physics, Azienda USL-IRCCS di Reggio Emilia, Italy. Electronic address:

Background And Objectives: Malignant lymphomas are cancers of the immune system and are characterized by enlarged lymph nodes that typically spread across many different sites. Many different histological subtypes exist, whose diagnosis is typically based on sampling (biopsy) of a single tumor site, whereas total body examinations with computed tomography and positron emission tomography, though not diagnostic, are able to provide a comprehensive picture of the patient. In this work, we exploit a data-driven approach based on multiple-instance learning algorithms and texture analysis features extracted from positron emission tomography, to predict differential diagnosis of the main malignant lymphomas subtypes.

Methods: We exploit a multiple-instance learning setting where support vector machines and random forests are used as classifiers both at the level of single VOIs (instances) and at the level of patients (bags). We present results on two datasets comprising patients that suffer from four different types of malignant lymphomas, namely diffuse large B cell lymphoma, follicular lymphoma, Hodgkin's lymphoma, and mantle cell lymphoma.

Results: Despite the complexity of the task, experimental results show that, with sufficient data samples, some cancer subtypes, such as the Hodgkin's lymphoma, can be identified from texture information: in particular, we achieve a 97.0% of sensitivity (recall) and a 94.1% of predictive positive value (precision) on a dataset that consists in 60 patients.

Conclusions: The presented study indicates that texture analysis features extracted from positron emission tomography, combined with multiple-instance machine learning algorithms, can be discriminating for different malignant lymphomas subtypes.
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http://dx.doi.org/10.1016/j.cmpb.2019.105153DOI Listing
March 2020

Characterization of GE discovery IGS 740 angiography system by means of channelized Hotelling observer (CHO).

Phys Med Biol 2019 04 23;64(9):095002. Epub 2019 Apr 23.

Servizio di Fisica Medica, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy. Author to whom correspondence may be addressed.

The aim of the study is to use the well-known channelized Hotelling observer model (CHO) to characterize a recently installed angiography system (GE Discovery IGS 740) using sets of images of a contrast-detail phantom acquired with clinical protocols. A Leeds TO10 phantom was used. The phantom has 108 details: 12 diameters (size range: 0.25 mm-11 mm), each with nine contrasts (declared range: 0.012-0.930 at 70 kVp 1.00 with 1 mm Cu filtration). TO10 has been imaged between two 10 cm thick homogeneous solid water slabs. Two FOVs (32 cm and 20 cm) were used. Fluoroscopy images were taken using an abdominal protocol at two different frame rates (15 fps and 7.5 fps) and at two dose levels (low and normal); cineangiography images were acquired using an abdominal protocol at 15 fps at two dose levels (low and normal). A 40 Gabor channels CHO with internal noise was used. Human observers' studies were carried out to tune the internal noise parameter and to validate the model observer. Contrast-detail curves were obtained from the CHO output using a visibility threshold of 75% and fitted with Rose's model theory in order to characterize the angiography system. Wilcoxon rank-sum tests were performed to investigate possible differences among the different sets of images. The CHO can distinguish between the two dose levels (p -values  <  0.002), while FOV and frame rate do not affect the contrast-detail curves significantly. It is important to note that the CHO does not find statistically significant differences between a fluoroscopy with FOV  =  20 cm at normal dose level (17.6 mGy min) and a cineangiography with FOV  =  32 cm low dose level (42.1 mGy min). This result can lead to a dose reduction of about 70% for our specific task (i.e. a static, disc shaped object at known location in homogeneous field). Given their stability in comparison to human observers, model observers provide an effective tool for image quality evaluation.
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http://dx.doi.org/10.1088/1361-6560/ab144cDOI Listing
April 2019

Partial volume effect of SPECT images in PRRT with 177Lu labelled somatostatin analogues: A practical solution.

Phys Med 2019 Jan 8;57:153-159. Epub 2019 Jan 8.

Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Medical Physics Unit, Reggio Emilia, Italy.

Background: At present activity quantification is one of the most critical step in dosimetry calculation, and Partial Volume Effect (PVE) one of the most important source of error. In recent years models based upon phantoms that incorporate hot spheres have been used to establish recovery models. In this context the goal of this study was to point out the most critical issues related to PVE and to establish a model closer to a biological imaging environment.

Methods: Two different phantoms, filled with a Lu solution, were used to obtain the PVE Recovery Coefficients (RCs): a phantom with spherical inserts and a phantom with organ-shaped inserts. Two additional phantoms with inserts of various geometrical shapes and an anthropomorphic phantom were acquired to compare the real activities to predicted values after PVE correction.

Results: The RCs versus volume of the inserts produced two different curves, one for the spheres and one for the organs. After PVE correction, accuracy on activity quantification averaged over all inserts of three test phantoms passed from -26% to 1.3% (from 26% to 10% for absolute values).

Conclusion: RCs is a simple method for PVE correction easily applicable in clinical routine. The use of two different models for organs and lesions has permitted to closely mimic the situation in a living subject. A marked improvement in the quantification of activity was observed when PVE correction was adopted, even if further investigations should be performed for more accurate models of PVE corrections.
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http://dx.doi.org/10.1016/j.ejmp.2018.12.029DOI Listing
January 2019

Pareto-optimal plans as ground truth for validation of a commercial system for knowledge-based DVH-prediction.

Phys Med 2018 Nov 10;55:98-106. Epub 2018 Nov 10.

Department of Radiation Oncology, Erasmus MC Cancer Institute, Rotterdam, the Netherlands.

Purpose: Treatment plans manually generated in clinical routine may suffer from variations and inconsistencies in quality. Using such plans for validating a DVH prediction algorithm might obscure its intrinsic prediction accuracy. In this study we used a recently published large database of Pareto-optimal prostate cancer plans to assess the prediction accuracy of a commercial knowledge-based DVH prediction algorithm, RapidPlan. The database plans were consistently generated with automated planning using an independent optimizer, and can be considered as aground truth of plan quality.

Methods: Prediction models were generated using training sets with 20, 30, 45, 55 and 114 Pareto-optimal plans. Model-20 and Model-30 were built using 5 groups of randomly selected training patients. For 60 independent Pareto-optimal validation plans, predicted and database DVHs were compared.

Results: For model-114, differences between predicted and database mean doses of more than ± 10% in rectum, anus and bladder, occurred for 23.3%, 55.0%, and 6.7% of the validation plans, respectively. For rectum V and V, differences outside the ±10% range were observed in 21.7% and 70.0% of validation plans, respectively. For 61.7% of validation plans, inaccuracies in predicted rectum DVHs resulted in a deviation in predicted NTCP for rectal bleeding outside ±10%. With smaller training sets the DVH prediction performance deteriorated, showing dependence on the selected training patients.

Conclusion: Even when analysed with Pareto-optimal plans with highly consistent quality, clinically relevant deviations in DVH predictions were observed. Such deviations could potentially result in suboptimal plans for new patients. Further research on DVH prediction models is warranted.
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http://dx.doi.org/10.1016/j.ejmp.2018.11.002DOI Listing
November 2018

Red blood cells metabolome changes upon treatment with different X-ray irradiation doses.

Ann Hematol 2018 Oct 7;97(10):1909-1917. Epub 2018 Jun 7.

Transfusion Medicine Unit, AUSL-IRCCS, Reggio Emilia, Italy.

The upholding of red blood cells (RBC) quality and the removal of leukocytes are two essential issues in transfusion therapy. Leukodepletion provides optimum results, nonetheless there are cases where irradiation is recommended for some groups of hematological patients such as the ones with chronic graft-vs-host disease, congenital cellular immunodeficiency, and hematopoietic stem cell transplant recipients. The European guidelines suggest irradiation doses from 25 to 50 Gray (Gγ). We evaluated the effect of different prescribed doses (15 to 50 Gγ) of X-ray irradiation on fresh leukodepleted RBCs bags using a novel protocol that provides a controlled irradiation. Biochemical assays integrated with RBCs metabolome profile, assessed by nuclear magnetic resonance spectroscopy, were performed on RBC units supernatant, during 14 days storage. Metabolome analysis evidenced a direct correlation between concentration increase of three metabolites, glycine, glutamine and creatine, and irradiation dose. Higher doses (35 and 50 Gγ) effect on RBC mean corpuscular volume, hemolysis, and ammonia concentration are considerable after 7 and 14 days of storage. Our data show that irradiation with 50 Gγ should be avoided and we suggest that 35 Gγ should be the upper limit. Moreover, we suggest for leukodepleted RBCs units the irradiation with the prescribed dose of 15 Gγ, value at center of bag, and ranging between 13.35-15 Gγ, measured over the entire bag volume, may guarantee the same benefits of a 25 Gγ dose assuring, in addition, a better quality of RBCs.
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http://dx.doi.org/10.1007/s00277-018-3386-6DOI Listing
October 2018

Effect of image registration on 3D absorbed dose calculations in Lu-DOTATOC peptide receptor radionuclide therapy.

Phys Med 2018 Jan 8;45:177-185. Epub 2018 Jan 8.

Department of Medical Physics, Velindre Cancer Centre, Cardiff, Wales, UK; School of Engineering, Cardiff University, Cardiff, Wales, UK.

Peptide receptor radionuclide therapy (PRRT) is an effective MRT (molecular radiotherapy) treatment, which consists of multiple administrations of a radiopharmaceutical labelled with Lu or Y. Through sequential functional imaging a patient specific 3D dosimetry can be derived. Multiple scans should be previously co-registered to allow accurate absorbed dose calculations. The purpose of this study is to evaluate the impact of image registration algorithms on 3D absorbed dose calculation. A cohort of patients was extracted from the database of a clinical trial in PRRT. They were administered with a single administration of Lu-DOTATOC. All patients underwent 5 SPECT/CT sequential scans at 1 h, 4 h, 24 h, 40 h, 70 h post-injection that were subsequently registered using rigid and deformable algorithms. A similarity index was calculated to compare rigid and deformable registration algorithms. 3D absorbed dose calculation was carried out with the Raydose Monte Carlo code. The similarity analysis demonstrated the superiority of the deformable registrations (p < .001). Average absorbed dose to the kidneys calculated using rigid image registration was consistently lower than the average absorbed dose calculated using the deformable algorithm (90% of cases), with percentage differences in the range [-19; +4]%. Absorbed dose to lesions were also consistently lower (90% of cases) when calculated with rigid image registration with absorbed dose differences in the range [-67.2; 100.7]%. Deformable image registration had a significant role in calculating 3D absorbed dose to organs or lesions with volumes smaller than 100 mL. Image based 3D dosimetry for Lu-DOTATOC PRRT is significantly affected by the type of algorithm used to register sequential SPECT/CT scans.
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http://dx.doi.org/10.1016/j.ejmp.2017.11.021DOI Listing
January 2018

Knowledge-based treatment planning: An inter-technique and inter-system feasibility study for prostate cancer.

Phys Med 2017 Apr 17;36:38-45. Epub 2017 Mar 17.

Medical Physics Unit, Department of Advanced Technology, Arcispedale Santa Maria Nuova, IRCCS, Reggio Emilia, Italy. Electronic address:

Purpose: Helical Tomotherapy (HT) plans were used to create two RapidPlan knowledge-based (KB) models to generate plans with different techniques and to guide the optimization in a different treatment planning system for prostate plans. Feasibility and performance of these models were evaluated.

Material And Methods: two sets of 35 low risk (LR) and 30 intermediate risk (IR) prostate cancer cases who underwent HT treatments were selected to train RapidPlan models. The KB predicted constraints were used to perform new 20KB plans using RapidArc technique (KB-RA) (inter-technique validation), and to optimise 20 new HT (KB-HT) plans in the Tomoplan (inter-system validation). For each validation modality, KB plans were benchmarked with the manual plans created by an expert planner (EP).

Results: RapidPlan was successfully configured using HT plans. The KB-RA plans fulfilled the clinical dose-volume requirements in 100% and 92% of cases for planning target volumes (PTVs) and organs at risk (OARs), respectively. For KB-HT plans these percentages were found to be a bit lower: 90% for PTVs and 86% for OARs. In comparison to EP plans, the KB-RA plans produced higher bladder doses for both LR and IR, and higher rectum doses for LR. KB-HT and EP plans produced similar results.

Conclusion: RapidPlan can be trained to create models by using plans of a different treatment modality. These models were suitable for generating clinically acceptable plans for inter-technique and inter-system applications. The use of KB models based on plans of consolidated technique could be useful with a new treatment modality.
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http://dx.doi.org/10.1016/j.ejmp.2017.03.002DOI Listing
April 2017

Technical Note: Multicenter study of TrueBeam FFF beams with a new stereotactic diode: Can a common small field signal ratio curve be defined?

Med Phys 2016 Oct;43(10):5570

Medical Physics Unit of Radiation Oncology Department, Humanitas Clinical and Research Center, Milano-Rozzano, 20089, Italy.

Purpose: Small radiation fields (<30 mm) are typically involved in stereotactic body radiation therapy procedures. Output factor measurements are subjected to large uncertainties. The signal ratio (SR) readings, defined as the ratio of central axis reading, respectively, in the actual field size and in the reference field size, were evaluated in several centers and a common mathematical description of the SR curve was investigated.

Methods: A couple of new unshielded stereotactic diodes (Razor, IBA) was tested under eight different TrueBeams using 10 MV flattering filter free beams with high dose rate (2400 MU/min). Small fields, ranging from 6 to 50 mm, were analyzed in terms of profiles and central axis point measurements. SRs were normalized to 30 mm field and were calculated as a function of nominal field size (NFS) and effective field size (EFS). From SRs acquired using Razor1 (four centers), a theoretical equation was extrapolated. Three centers with Razor2 were used to test the mathematical relationship. Finally, the two diodes were directly compared in the last center.

Results: The EFS was systematically smaller than NFS (p < 0.01) for all field size ranges, with mean difference of 0.9 ± 0.5 mm. The SR fits using the NFS and EFS had, respectively, R = 0.989 and R ≫ 0.999. The Razor2 centers' mean deviation from the predicted SRs, using the NFS and EFS fits, was, respectively, 3.4% and 0.5%. The maximum deviations were 5.0% (6 mm field size) for NFS and 1.9% for EFS. Maximum deviation of 0.5% between the two Razors was observed.

Conclusions: EFS measurements were confirmed to be mandatory when comparing SRs over different centers. An equation establishing a functional relation between SRs and the EFS was obtained and tested for the new Razor diode.
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http://dx.doi.org/10.1118/1.4961744DOI Listing
October 2016

Skin dose saving of the staff in 90Y/177Lu peptide receptor radionuclide therapy with the automatic dose dispenser.

Nucl Med Commun 2016 Oct;37(10):1046-52

aMedical Physics Unit bNuclear Medicine Unit, Arcispedale Santa Maria Nuova - IRCCS, Reggio Emilia cDepartment of Industrial Engineering, University of Bologna, Bologna, Italy.

Objective: When handling Y-labelled and Lu-labelled radiopharmaceuticals, skin exposure is mainly due to β-particles. This study aimed to investigate the equivalent dose saving of the staff when changing from an essentially manual radiolabelling procedure to an automatic dose dispenser (ADD).

Materials And Methods: The chemist and physician were asked to wear thermoluminescence dosimeters on their fingertips to evaluate the quantity of Hp(0.07) on the skin. Data collected were divided into two groups: before introducing ADD (no ADD) and after introducing ADD.

Results: For the chemist, the mean values (95th percentile) of Hp(0.07) for no ADD and ADD are 0.030 (0.099) and 0.019 (0.076) mSv/GBq, respectively, for Y, and 0.022 (0.037) and 0.007 (0.023) mSv/GBq, respectively, for Lu. The reduction for ADD was significant (t-test with P<0.05) for both isotopes. The relative differences before and after ADD collected for every finger were treated using the Wilcoxon test, proving a significantly higher reduction in extremity dose to each fingertip for Lu than for Y (P<0.05). For the medical staff, the mean values of Hp(0.07) (95th percentile) for no ADD and ADD are 0.021 (0.0762) and 0.0143 (0.0565) mSv/GBq, respectively, for Y, and 0.0011 (0.00196) and 0.0009 (0.00263) mSv/GBq, respectively, for Lu. The t-test provided a P-value less than 0.05 for both isotopes, making the difference between ADD and no ADD significant.

Conclusion: ADD positively affects the dose saving of the chemist in handling both isotopes. For the medical staff not directly involved with the introduction of the ADD system, the analysis shows a learning curve of the workers over a 5-year period. Specific devices and procedures allow staff skin dose to be limited.
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http://dx.doi.org/10.1097/MNM.0000000000000548DOI Listing
October 2016

Second Tumor Induction Risk in IMRT for Prostate Cancer: An Unbalanced Comparison Between Surgery and Radiotherapy?

Health Phys 2015 Dec;109(6):549-55

*Medical Physics Department, IRCCS San Raffaele Scientific Institute, Milan Italy; †Medical Physics Department, IRCCS Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy; ‡Radiotherapy Department, IRCCS San Raffaele Scientific Institute, Milan Italy.

The aim of this study was to evaluate the risk of second tumor induction for prostate patients treated with volumetric modulated arc therapy in age classes 50-70. Based on both age-dependent models and doses to critical organs, the risk of second tumor induction was evaluated simulating the small field (prostate and seminal vesicles) and large field (whole pelvis) for Helical Tomotherapy and Rapid Arc. The doses to the organs closest to the treatment volume were derived from treatment planning system data. Whereas, due to the lack of calculation algorithms where leakage and internal radiation scattering are unreliable at a large distance from target, the doses to the organs outside the treatment volume were measured in an anthropomorphic phantom. Doses from Image Guided Radiotherapy (IGRT) were also assessed on phantom measurements. The Lifetime Attributable Risk (LAR) for second tumor induction increases from 2.2 to 13.7% as irradiated volume increases and age decreases. IGRT could add a non-negligible factor to the risk when daily set-up verification with high-resolution modality is included. As prostate cancer is detected earlier, the probability of an increase in early stage patients rises, and life expectancy thus increases. Radiotherapy has improved its capability in the tailoring of the dose around the target at the cost of a greater dose to surrounding organs, thus increasing the risk of second tumor induction, especially for those patients expected to survive 15 y or more.
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http://dx.doi.org/10.1097/HP.0000000000000362DOI Listing
December 2015

Time Evolution of DOTATOC Uptake in Neuroendocrine Tumors in View of a Possible Application of Radioguided Surgery with β- Decay.

J Nucl Med 2015 Oct 3;56(10):1501-6. Epub 2015 Sep 3.

Dipartimento di Fisica, Sapienza Università di Roma, Roma, Italy INFN Sezione di Roma, Roma, Italy

Unlabelled: A novel radioguided surgery (RGS) technique exploiting β- radiation has been proposed. To develop such a technique, a suitable radiotracer able to deliver a β- emitter to the tumor has to be identified. A first candidate is represented by 90Y-labeled DOTATOC, a compound commonly used today for peptide radioreceptor therapy. The application of this β- RGS to neuroendocrine tumors (NET) requires study of the uptake of DOTATOC and its time evolution both in tumors and in healthy organs and evaluation of the corresponding performance of the technique.

Methods: Uptake by lesions and healthy organs (kidneys, spleen, liver and healthy muscle) was estimated on 177Lu-DOTATOC SPECT/CT scans of 15 patients affected by NET with different localizations, treated at IRCCS-Arcispedale Santa Maria Nuova, Reggio Emilia, Italy. For each patient, SPECT/CT images, acquired at 0.5, 4, 20, 40, and 70 h after injection, were studied. For each lesion, the tumor-to-nontumor ratio (TNR) with respect to all healthy organs and its time evolution were studied. A subset of patients showing hepatic lesions was selected, and the TNR with respect to the nearby healthy tissue was calculated. By means of a Monte Carlo simulation of the probe for β- RGS, the activity that is to be administered for a successful detection was estimated lesion-by-lesion.

Results: Uptake of DOTATOC on NETs maximized at about 24 h after injection. The cases of hepatic lesions showed a TNR with respect to the tumor margins compatible with the application of β- RGS. In particular, 0.1-mL residuals are expected to be detectable within 1 s with 5% false-negative and 1% false-positive by administering the patient as little as 1 MBq/kg.

Conclusion: The balance between tumor uptake and metabolic washout in healthy tissue causes the TNR to increase with time, reaching its maximum after 24 h, and this characteristic can be exploited when a radiotracer with a long half-life, such as 90Y, is used. In particular, if 90Y-DOTATOC is used with liver NET metastases, the proposed RGS technique is believed to be feasible by injecting an activity that is one third of that commonly used for PET imaging.
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http://dx.doi.org/10.2967/jnumed.115.160481DOI Listing
October 2015

Diagnostic performances of [18F]fluorocholine positron emission tomography in brain tumors.

Q J Nucl Med Mol Imaging 2018 Jun 1;62(2):209-219. Epub 2015 Sep 1.

Unit of Nuclear Medicine, Santa Maria Nuova Hospital, Institute for Research and Care of Reggio Emilia, Reggio Emilia, Italy.

Background: Brain tumors characterization by molecular imaging that allows the depiction of brain lesions metabolic pattern is crucial. Our study aimed to: 1) to evaluate the diagnostic performances of [18F]fluoroethylcholine positron emission tomography/computed tomography ([18F]FECH PET/CT), and 2) correlate PET imaging derived parameters of [18F]FECH to survival in brain tumors.

Methods: From 2009 to 2012, we enrolled 30 patients who underwent [18F]FECH PET/CT. Final diagnosis was established by clinical and radiological follow-up.

Results: Final diagnosis was consistent with tumor disease in 27/30 cases. In 3/30 cases tumor disease was ruled out. [18F]FECH PET/CT resulted true positive and negative in 21/30 and 9/30 patients, respectively. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of [18F]FECH PET/CT were 78%, 100%, 100%, 33%, and 80%, respectively. Mean and maximum standardized uptake value (SUVmean and SUVmax) resulted statistically correlated to histology (P=0.0255 and P=0.0222, respectively). Using a SUVmax cut-off of 2.0 or 3.2, we distinguished between low- and high-grade gliomas with a good specificity (70% and 80%, respectively). SUVmax and histology resulted correlated to overall survival and disease related survival at multivariate analysis.

Conclusions: Our results, worthy of further investigations, show high diagnostic performances of [18F]FECH PET/CT, and a correlation between PET imaging derived parameters and survival.
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http://dx.doi.org/10.23736/S1824-4785.17.02807-2DOI Listing
June 2018

RIS-PACS, patient safety, and clinical risk management.

Radiol Med 2015 Jun 16;120(6):498-503. Epub 2014 Dec 16.

Medical Physics Unit, Arcispedale Santa Maria Nuova Hospital IRCCS, Reggio Emilia, Italy,

Purpose: Clinical risk management is the basis of safety procedures also in radiological workflows. In the literature, it has been documented that the incidence of reconciled radiological studies ranges between 0.2 and 0.5 % of stored studies, a non-negligible value if we consider the high number of diagnostic tests performed.

Materials And Methods: In radiology, "non-compliance" or, more generally, data to be reconciled means any circumstance in which wrong information is recorded in RIS and/or PACS, which requires processing to amend or correct images, reports or other information in order to attribute them to the right patient/episode. Non-compliance corrections account for almost 50 % of the medical system administrator's (SA) workload. This paper describes how the Reggio Emilia Province Diagnostic Imaging and Laboratory Medicine Department manages risk in clinical radiology, in compliance with Regional indications on RIS-PACS safety. A dedicated RIS webpage has been developed in order to manage reconciliation requests. Native integration with PACS makes information about ongoing reconciliations available to anyone who consults the images.

Results: In 2013, non-compliances reported by radiology staff ranged between 0.25 and 0.35 % of studies sent to the PACS. More than 50 % of non-compliances can be related to high clinical risk, which requires implementation of efficient and effective rapid mechanisms of action-reaction inside and outside the radiology department.

Conclusions: The RIS-integrated module has been the starting point for managing and monitoring errors, allowing improvement initiatives to guarantee and optimise workflow. Request and event traceability have allowed us to define personalised training programmes, designed to minimise procedural and/or systematic errors. To protect the availability and consistency of information produced by radiology units, it is necessary to provide integrated and effective mechanisms for reconciliation management. The integrated tool described in this paper is now widely used (not only by our centre): radiographers and radiologists can indicate non-compliances in an efficient and effective manner, informing all the operators involved with just a click of the mouse. Similar functionality should be implemented in the next generation of RIS-PACS in order to maintain the highest possible safety level for patients and workers.
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http://dx.doi.org/10.1007/s11547-014-0483-zDOI Listing
June 2015

Radiation protection procedures in 131I treatments for thyroid cancer in patients requiring hemodialysis.

Nucl Med Commun 2014 Jun;35(6):626-30

aMedical Physics Unit bNuclear Medicine Unit, Arcispedale Santa Maria Nuova - IRCCS, Reggio Emilia, Italy.

Background: Hemodialysis is essential for patients with renal failure, and iodine-131 ((131)I) administration is the standard of care in thyroid carcinoma treatment. Although the need for hemodialysis during (131)I treatment is very rare, it raises some concerns due to the involvement of personnel not exposed to radiation and to the contamination of devices used for other patients. In this paper, a radioprotection protocol to perform hemodialysis safely on patients during (131)I treatment has been presented.

Patients And Methods: The exposure of personnel who assisted 13 patients over the course of 10 years was monitored: external exposure was measured through electronic dosimeters, and internal contamination was checked by thyroid uptake and urine sample gamma spectrometry. Over this period, room layout was optimized to allow an improvement of radioprotection procedures.Two nurses were involved in patient assistance.

Results: After hemodialysis, measurements of internal contamination were below the minimum detectable activity and external exposure was in the range of 1-82 μSv in terms of H(p)(10). A reduction in personnel exposure was observed after hospitalization room renovation: H(p)(10) normalized to the activity administered to the patient was about halved.

Conclusion: The data show that hemodialysis can be performed safely during I treatments when appropriate radioprotection actions are implemented.
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http://dx.doi.org/10.1097/MNM.0000000000000095DOI Listing
June 2014

MR scanner systems should be adequately characterized in diffusion-MRI of the breast.

PLoS One 2014 28;9(1):e86280. Epub 2014 Jan 28.

Department of Clinical and Experimental Biomedical Sciences, University of Florence, Florence, Italy ; Department of Electrical, Electronic, and Information Engineering "Guglielmo Marconi", University of Bologna, Cesena, Italy.

Breast imaging represents a relatively recent and promising field of application of quantitative diffusion-MRI techniques. In view of the importance of guaranteeing and assessing its reliability in clinical as well as research settings, the aim of this study was to specifically characterize how the main MR scanner system-related factors affect quantitative measurements in diffusion-MRI of the breast. In particular, phantom acquisitions were performed on three 1.5 T MR scanner systems by different manufacturers, all equipped with a dedicated multi-channel breast coil as well as acquisition sequences for diffusion-MRI of the breast. We assessed the accuracy, inter-scan and inter-scanner reproducibility of the mean apparent diffusion coefficient measured along the main orthogonal directions () as well as of diffusion-tensor imaging (DTI)-derived mean diffusivity (MD) measurements. Additionally, we estimated spatial non-uniformity of (NU) and MD (NUMD) maps. We showed that the signal-to-noise ratio as well as overall calibration of high strength diffusion gradients system in typical acquisition sequences for diffusion-MRI of the breast varied across MR scanner systems, introducing systematic bias in the measurements of diffusion indices. While and MD values were not appreciably different from each other, they substantially varied across MR scanner systems. The mean of the accuracies of measured and MD was in the range [-2.3%,11.9%], and the mean of the coefficients of variation for and MD measurements across MR scanner systems was 6.8%. The coefficient of variation for repeated measurements of both and MD was < 1%, while NU and NUMD values were <4%. Our results highlight that MR scanner system-related factors can substantially affect quantitative diffusion-MRI of the breast. Therefore, a specific quality control program for assessing and monitoring the performance of MR scanner systems for diffusion-MRI of the breast is highly recommended at every site, especially in multicenter and longitudinal studies.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0086280PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3904912PMC
December 2014

Hypofractionated stereotactic radiation therapy for recurrent glioblastoma: single institutional experience.

Radiat Oncol 2013 Sep 25;8:222. Epub 2013 Sep 25.

Radiation Therapy Unit, Department of Oncology and Advanced Technology, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Viale Risorgimento 80, 42123 Reggio Emilia, Italy.

Background: Glioblastoma (GBM) is the most common malignant primary brain tumor in adults. Tumor control and survival have improved with the use of radiotherapy (RT) plus concomitant and adjuvant chemotherapy, but the prognosis remain poor. In most cases the recurrence occurs within 7-9 months after primary treatment. Currently, many approaches are available for the salvage treatment of patients with recurrent GBM, including resection, re-irradiation or systemic agents, but no standard of care exists.

Methods: We analysed a cohort of patients with recurrent GBM treated with frame-less hypofractionated stereotactic radiation therapy with a total dose of 25 Gy in 5 fractions.

Results: Of 91 consecutive patients with newly diagnosed GBM treated between 2007 and 2012 with conventional adjuvant chemo-radiation therapy, 15 underwent salvage RT at recurrence. The median time interval between primary RT and salvage RT was 10.8 months (range, 6-54 months). Overall, patients undergoing salvage RT showed a longer survival, with a median survival of 33 vs. 9.9 months (p= 0.00149). Median overall survival (OS) from salvage RT was 9.5 months. No patients demonstrated clinically significant acute morbidity, and all patients were able to complete the prescribed radiation therapy without interruption.

Conclusion: Our results suggest that hypofractionated stereotactic radiation therapy is effective and safe in recurrent GBM. However, until prospective randomized trials will confirm these results, the decision for salvage treatment should remain individual and based on a multidisciplinary evaluation of each patient.
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http://dx.doi.org/10.1186/1748-717X-8-222DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3852333PMC
September 2013

Hypo-fractionated IMRT for patients with newly diagnosed glioblastoma multiforme: a 6 year single institutional experience.

Clin Neurol Neurosurg 2013 Sep 26;115(9):1609-14. Epub 2013 Feb 26.

Radiation Therapy Unit, Department of Oncology and Advanced Technology, Azienda Ospedaliera ASMN, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia, Italy.

Objectives: Glioblastoma (GBM) is the most common malignant primary brain tumour in adults. Surgery and radiotherapy constitute the cornerstones for the therapeutic management of GBM. The standard treatment today is maximal surgical resection followed by concomitant chemo-radiation therapy followed by adjuvant TMZ according to Stupp protocol. Despite the progress in neurosurgery, radiotherapy and oncology, the prognosis still results poor. In order to reduce the long time of standard treatment, maintaining or improving the clinical results, in our institute we have investigated the effects of hypo-fractionated radiation therapy for patients with GBM.

Patients And Methods: Sixty-seven patients affected by GBM who had previously undergone surgical resection (total, subtotal or biopsy) were enrolled between October 2005 and December 2011 in a single institutional study of hypo-fractionated intensity modulated radiation therapy (IMRT) followed or not by adjuvant chemotherapy with TMZ (6-12 cycles). The most important eligibility criteria were: biopsy-proven GBM, KPS ≥ 60, age ≥ 18 years, no previous brain irradiation, informed consensus. Hypo-fractionated IMRT was delivered to a total dose of 25 Gy in 5 fractions prescribed to 70% isodose. Response to treatment, OS, PFS, toxicity and patterns of recurrence were evaluated, and sex, age, type of surgery, Karnofsky performance status, Recursive Partitioning Analysis (RPA) classification, time between surgery and initiation of radiotherapy were evaluated as potential prognostic factors for survival.

Results: All patients have completed the treatment protocol. Median age was 64.5 years (range 41-82 years) with 31 females (46%) and 36 males (54%). Median KPS at time of treatment was 80. The surgery was gross total in 38 patients and subtotal in 14 patients; 15 patients underwent only biopsy. No grade 3-4 acute or late neurotoxicity was observed. With median follow-up of 14.9 months, the median OS and PFS were 13.4 and 7.9 months, respectively.

Conclusions: The hypo-fractionated radiation therapy can be used for patients with GBM, resulting in favourable overall survival, low rates of toxicity and satisfying QoL. Future investigations are needed to determine the optimal fractionation for GBM.
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http://dx.doi.org/10.1016/j.clineuro.2013.02.001DOI Listing
September 2013

Efficiency and effectiveness of an innovative RIS function for patient information reconciliation directly integrated with PACS.

J Digit Imaging 2013 Jun;26(3):412-8

Department of Advanced Technology, Medical Physics Unit, Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy.

In RIS-PACS systems, potential errors occurring during the execution of a radiologic examination can amplify the clinical risks of the patient during subsequent treatments, e.g., of oncologic patients or of those who must do additional treatments based on the initial diagnosis. In Reggio Emilia Province Diagnostic Imaging Department (REDID) we experienced different strategies to reduce clinical risks due to patient reconciliation errors. In 2010, we developed a procedure directly integrated in our RIS-PACS that uses Health Level 7 (HL7) standard messaging, which generates an overlay with the text "under investigation" on the images of the study to be corrected. All the healthcare staff is informed of the meaning of that overlay, and only the radiologist and the emergency services staff can consult these images on PACS. The elimination of image overlay and of any access limitation to PACS was triggered to confirm of the right correction made by RIS-PACS system administrator (SA). The RIS-PACS integrated tool described in this paper allows technologists and radiologists to efficiently highlight patient exam errors and to inform all the users to minimize the overall clinical risks, with a significant savings in costs. Over the years, we have observed a steady decrease in the percentage of reconciled studies. Error reconciliation requires an effective and efficient mechanism. The RIS-PACS integrated tool described in this paper enables technologists and radiologists to quickly and efficiently highlight patient exam errors and inform all the users. Next generation of RIS-PACS could be equipped with similar reconciliation tools.
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http://dx.doi.org/10.1007/s10278-012-9558-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3649044PMC
June 2013

A comparison of digital radiography systems in terms of effective detective quantum efficiency.

Med Phys 2012 May;39(5):2617-27

Department of Advanced Technology, Istituto di Ricovero e Cura a Carattere Scientifico, Reggio Emilia, Italy.

Purpose: The purpose of this study is to compare digital radiography systems using the metric effective detective quantum efficiency (eDQE), which better reflects digital radiography imaging system performance under clinical operating conditions, in comparison with conventional metrics such as modulation transfer function (MTF), normalized noise power spectra (NNPS), and detective quantum efficiency (DQE).

Methods: The eDQE was computed by the calculation of the MTF, the NNPS, the phantom attenuation and scatter, and estimation of x-ray flux. The physical characterization of the systems was obtained with the standard beam conditions RQA5 and RQA9, using the PA Chest phantom proposed by AAPM Report # 31 simulating the attenuation and scatter characteristics of the adult human thorax. The MTF (eMTF) was measured by using an edge test placed at the frontal surface of the phantom, the NNPS (eNNPS) was calculated from images of the phantom acquired at three different exposure levels covering the operating range of the system (E(0), which is the exposure at which a system is normally operated, 1/3 E(0), and 3 E0), and scatter measurements were assessed by using a beam-stop technique. The integral of DQE (IDQE) and eDQE (IeDQE) was calculated over the whole spatial frequency range.

Results: The eMTF results demonstrate degradation due to magnification and the presence of scattered radiation. The eNNPS was influenced by the grid presence, and in some systems, it contained structured noise. At typical clinical exposure levels, the magnitude of eDQE(0) with respect to DQE(0) at RQA9 beam conditions was 13%, 17%, 16%, 36%, and 24%, respectively, for Carestream DRX-1, Carestream DRX-1C, Carestream Direct View CR975, Philips Digital Diagnost VM, and GE Revolution XR/d. These results were confirmed by the ratio of IeDQE and IDQE in the same conditions.

Conclusions: The authors confirm the robustness and reproducibility of the eDQE method. As expected, the DR systems performed better than the CR systems due to their superior signal-to-noise transfer characteristics. The results of this study suggest the eDQE method may provide an opportunity to more accurately assess the clinical performance of digital radiographic imaging systems by accounting for factors such as the presence of scatter, use of an antiscatter grid, and magnification and focal spot blurring effects, which are not reflected in conventional DQE measures.
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http://dx.doi.org/10.1118/1.4704500DOI Listing
May 2012

Personnel exposure in labelling and administration of (177)Lu-DOTA-D-Phe1-Tyr3-octreotide.

Nucl Med Commun 2011 Oct;32(10):947-53

Department of Medical Physics, Nuclear Medicine, Arcispedale S. Maria Nuova, Reggio Emilia, Italy.

Objective: The introduction of peptide receptor radionuclide therapy, mainly performed with (90)Y and (177)Lu-labelled somatostatin analogues, has widened the therapeutic horizon of nuclear medicine.The handling of (177)Lu-labelled pharmaceuticals implies an increase of the personnel exposure and this aspect is evaluated in this paper, in comparison with personal exposure in (90)Y manipulation.

Materials And Methods: Personal dose measurements were performed during 26 (177)Lu-DOTATOC preparations by using a series of thin active layer LiF: Mg,Cu,P thermoluminescence dosimeters fixed at the operator's fingertips to evaluate the skin equivalent dose and by means of direct reading dosimeters positioned at the chest to evaluate the personal effective dose. Individual protection devices, such as shielded aprons and anti-X gloves, were also used.

Results: The 95th percentile of the skin equivalent dose distribution for (177)Lu operations by using 0.20-mm anti-X gloves was 0.080 mSv/GBq for the chemist and 0.011 mSv/GBq for the physician, whereas the 75th percentile was 0.058 mSv/GBq for the chemist and 0.006 mSv/GBq for the physician. The use of the 0.25 mm Pb-equivalent anti-X apron halved the personal equivalent dose measured over the apron by a direct reading dosimeter. Skin doses were compared with (90)Y-DOTATOC procedures: no relevant exposure reduction is observed for chemists, whereas doses are considerably lower during administration procedures performed by physicians.

Conclusion: In this study, an evaluation of the skin equivalent doses during (177)Lu-DOTATOC labelling and administration is presented. These data can be useful to assess the risk for workers in centres that are starting to implement PRRT using (177)Lu. The use of appropriate protection devices and procedures allows the observance of International Commission for Radiological Protection dose limits for exposed workers.
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http://dx.doi.org/10.1097/MNM.0b013e328349fd60DOI Listing
October 2011

Comparison of two different types of LiF:Mg,Cu,P thermoluminescent dosimeters for detection of beta rays (beta-TLDs) from 90Sr/90Y, 85Kr and 147Pm sources.

Health Phys 2011 May;100(5):515-22

Medical Physics Department, Santa Maria Nuova Hospital, Reggio Emilia, Italy.

Targeted radionuclide therapies in nuclear medicine departments increasingly depend on using unsealed beta radiation sources in the labeling of peptides and antibodies. Monitoring doses received by the fingers and hands during these procedures is best accomplished with TLD dosimeters that can be located at the fingertips. The present study examines the response of two TLD dosimeters (MCP-Ns and GR200A) to 90Sr/90Y, 85Kr, and 147Pm. The dosimeters were supplied by two different services, and all irradiations were performed at the PTB Institute in Germany. Each dosimetry service evaluated the dosimeters without knowledge that they had been purposefully irradiated. The accuracy and precision of the dosimeters were evaluated as a function of delivered dose, energy of beta particles and angular incidence. The results are compared to performance measures recommended by the IEC. Both dosimeter types displayed significant energy dependence. Angular dependence was moderate. Accuracy and precision as a function of dose (linearity) differed between the two systems, with the MCP-Ns being noticeably better than the GR200A. The superior precision makes the MCP-Ns much more useful for extremity dose measurements. The differences between these two dosimeter systems reinforce the need to evaluate a dosimeter carefully before using it in the daily work routine.
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http://dx.doi.org/10.1097/HP.0b013e3182092732DOI Listing
May 2011

Increase in clusterin forms part of the stress response in Hodgkin's lymphoma.

Int J Oncol 2011 Mar 14;38(3):677-84. Epub 2011 Jan 14.

Hematology Division, Azienda Ospedaliera S. Maria Nuova, Reggio Emilia, Italy.

Clusterin (also called APOJ, SGP-2, XIP8) has thus far been only partially characterized in lymphomas contrary to other types of cancer. Its expression has been reported only for anaplastic large cell lymphomas and, more recently, in mycosis fungoides. Here, we demonstrate an up-regulation of intracellular clusterin in Hodgkin's lymphoma (HL)-derived cell lines L-428, KM-H2 and L-540, caused by different stimuli such as IFN-γ, doxorubicin and X-rays. These stimuli are relevant for the pathophysiology and therapy of HL and represent a first step in the characterisation of this glycoprotein known to have a role in drug chemoresistance. p53 up-regulation accompanies increases in clusterin levels accordingly with the onset of apoptosis. We also show that the cells secrete more clusterin after treatment with doxorubicin, which is consistent with the observed intracellular increase. These observations suggested that the levels of circulating clusterin should also be measured in the peripheral blood from HL patients both at the time of diagnosis and after two cycles of chemotherapy. In a preliminary study on patient sera we observed that an increase in clusterin is correlated with positron emission tomography (PET) positivity after two cycles of chemotherapy.
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http://dx.doi.org/10.3892/ijo.2011.907DOI Listing
March 2011

Dosimetric verification of IMAT delivery with a conventional EPID system and a commercial portal dose image prediction tool.

Med Phys 2010 Jan;37(1):377-90

Servizio di Fisica Sanitaria, Arceispedale S. Maria Nuova, Reggio Emilia 42100, Italy.

Purpose: The electronic portal imaging device (EPID) is a system for checking the patient setup; as a result of its integration with the linear accelerator and software customized for dosimetry, it is increasingly used for verification of the delivery of fixed-field intensity-modulated radiation therapy (IMRT). In order to extend such an approach to intensity-modulated arc therapy (IMAT), the combined use of an EPID system and a portal dose image prediction (PDIP) tool has been investigated.

Methods: The dosimetric behavior of an EPID system, mechanically reinforced to maintain its positional stability during the accelerator gantry rotation, has been studied to assess its ability to measure portal dose distributions for IMAT treatment beams. In addition, the PDIP tool of a commercial treatment planning system, commonly used for static IMRT dosimetry, has been validated for simulating the PDIs of IMAT treatment fields. The method has been applied to the delivery verification of 23 treatment fields that were measured in their dual mode of IMRT and IMAT modalities.

Results: The EPID system has proved to be appropriate for measuring the PDIs of IMAT fields; additionally the PDIP tool was able to simulate these accurately. The results are quite similar to those obtained for static IMRT treatment verification, although it was necessary to investigate the dependence of the EPID signal and of the accelerator monitor chamber response on variable dose rate.

Conclusions: Our initial tests indicate that the EPID system, together with the PDIP tool, is a suitable device for the verification of IMAT plan delivery; however, additional tests are necessary to confirm these results.
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http://dx.doi.org/10.1118/1.3271107DOI Listing
January 2010

Dose-volume and biological-model based comparison between helical tomotherapy and (inverse-planned) IMAT for prostate tumours.

Radiother Oncol 2008 Jul 7;88(1):34-45. Epub 2008 Apr 7.

Department of Medical Physics, S. Maria Nuova Hospital, Reggio Emilia, Italy.

Background And Purpose: Helical tomotherapy (HT) and intensity-modulated arc therapy (IMAT) are two arc-based approaches to the delivery of intensity-modulated radiotherapy (IMRT). Through plan comparisons we have investigated the potential of IMAT, both with constant (conventional or IMAT-C) and variable (non-conventional or IMAT-NC, a theoretical exercise) dose-rate, to serve as an alternative to helical tomotherapy.

Materials And Methods: Six patients with prostate tumours treated by HT with a moderately hypo-fractionated protocol, involving a simultaneous integrated boost, were re-planned as IMAT treatments. A method for IMAT inverse-planning using a commercial module for static IMRT combined with a multi-leaf collimator (MLC) arc-sequencing was developed. IMAT plans were compared to HT plans in terms of dose statistics and radiobiological indices.

Results: Concerning the planning target volume (PTV), the mean doses for all PTVs were similar for HT and IMAT-C plans with minimum dose, target coverage, equivalent uniform dose (EUD) and tumour control probability (TCP) values being generally higher for HT; maximum dose and degree of heterogeneity were instead higher for IMAT-C. In relation to organs at risk, mean doses and normal tissue complication probability (NTCP) values were similar between the two modalities, except for the penile bulb where IMAT was significantly better. Re-normalizing all plans to the same rectal toxicity (NTCP=5%), the HT modality yielded higher TCP than IMAT-C but there was no significant difference between HT and IMAT-NC. The integral dose with HT was higher than that for IMAT.

Conclusions: with regards to the plan analysis, the HT is superior to IMAT-C in terms of target coverage and dose homogeneity within the PTV. Introducing dose-rate variation during arc-rotation, not deliverable with current linac technology, the simulations result in comparable plan indices between (IMAT-NC) and HT.
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http://dx.doi.org/10.1016/j.radonc.2008.03.003DOI Listing
July 2008