Publications by authors named "Enrico Menghi"

12 Publications

  • Page 1 of 1

The influence of basic plan parameters on calculated small field output factors - A multicenter study.

Phys Med 2021 Jun 30;88:98-103. Epub 2021 Jun 30.

Medical Physics Unit of Radiation Oncology Dept., Humanitas Clinical and Research Hospital, Rozzano-Milan, Italy.

Purpose: The influence of basic plan parameters such as slice thickness, grid resolution, algorithm type and field size on calculated small field output factors (OFs) was evaluated in a multicentric study.

Methods And Materials: Three computational homogeneous water phantoms with slice thicknesses (ST) 1, 2 and 3 mm were shared among twenty-one centers to calculate OFs for 1x1, 2x2 and 3x3 cm field sizes (FSs) (normalized to 10x10 cm FS), with their own treatment planning system (TPS) and the energy clinically used for stereotactic body radiation therapy delivery. OFs were calculated for each combination of grid resolution (GR) (1, 2 and 3 mm) and ST and finally compared with the OFs measured for the TPS commissioning. A multivariate analysis was performed to test the effect of basic plan parameters on calculated OFs.

Results: A total of 509 data points were collected. Calculated OFs are slightly higher than measured ones. The multivariate analysis showed that Center, GR, algorithm type, and FS are predictive variables of the difference between calculated and measured OFs (p < 0.001). As FS decreases, the spread in the difference between calculated and measured OFs became larger when increasing the GR. Monte Carlo and Analytical Anisotropic Algorithms, presented a dependence on GR (p < 0.01), while Collapsed Cone Convolution and Acuros did not. The effect of the ST was found to be negligible.

Conclusions: Modern TPSs slightly overestimate the calculated small field OFs compared with measured ones. Grid resolution, algorithm, center number and field size influence the calculation of small field OFs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2021.06.008DOI Listing
June 2021

The potential role of MR based radiomic biomarkers in the characterization of focal testicular lesions.

Sci Rep 2021 Feb 10;11(1):3456. Epub 2021 Feb 10.

Department of Morphology Surgery and Experimental Medicine, University of Ferrara, Via L. Ariosto 34, 44121, Ferrara, Italy.

How to differentiate with MRI-based techniques testicular germ (TGCTs) and testicular non-germ cell tumors (TNGCTs) is still under debate and Radiomics may be the turning key. Our purpose is to investigate the performance of MRI-based Radiomics signatures for the preoperative prediction of testicular neoplasm histology. The aim is twofold: (i), differentiating TGCTs and TNGCTs status and (ii) differentiating seminomas (SGCTs) from non-seminomatous (NSGCTs). Forty-two patients with pathology-proven testicular neoplasms and referred for pre-treatment MRI, were retrospectively enrolled. Thirty-two out of 44 lesions were TGCTs. Twelve out of 44 were TNGCTs or other histologies. Two radiologists segmented the volume of interest on T2-weighted images. Approximately 500 imaging features were extracted. Least Absolute Shrinkage and Selection Operator (LASSO) was applied as method for variable selection. A linear model and a linear support vector machine (SVM) were trained with selected features to assess discrimination scores for the two endpoints. LASSO identified 3 features that were employed to build fivefold validated linear discriminant and linear SVM classifiers for the TGCT-TNGCT endpoint giving an overall accuracy of 89%. Four features were employed to build another SVM for the SGCT-SNGCT endpoint with an overall accuracy of 86%. The data obtained proved that T2-weighted-based Radiomics is a promising tool in the diagnostic workup of testicular neoplasms by discriminating germ cell from non-gem cell tumors, and seminomas from non-seminomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-83023-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7875983PMC
February 2021

Radiation protection and dosimetry issues for patients with prostate cancer after I-125 low-dose-rate brachytherapy permanent implant.

Brachytherapy 2021 Jan-Feb;20(1):272-278. Epub 2020 Oct 9.

Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola FC, Italy.

Purpose: The aim of this work was to analyze the exposure rates measured in the proximity of patients who underwent prostate low-dose-rate brachytherapy with I-125 implant. Effective doses to relatives and to population were computed to estimate the time to reach radioprotection dose constraints.

Methods And Materials: Measurements were obtained from 180 patients, whereas the body mass index was calculated and reported for 77 patients. The day after the implant, K˙ measurements were conducted at various skin distances and positions and converted to effective doses. A theoretical model was developed to estimate effective doses from total implanted activity. The latter was approximated with a 10-mL vial inside the patient.

Results: The K˙ measurements showed a low correlation with the total implanted activity, albeit an increasing trend of K˙ was observed on increasing the activity. A stronger correlation was found between body mass index and K˙ measurements. The effective dose to population is in general lower than dose constraints as well as the effective doses to relatives, with the exception of children and pregnant women, who command special precautions. We report differences between the experimental model- and theoretical model-based dose evaluation together with their comparison with previous studies found in literature.

Conclusions: Based on the K˙ measurements and the results of the present analysis, it is possible to provide the patient with radiation safety instructions specifically tailored to his relatives' habits and working environment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.brachy.2020.09.003DOI Listing
October 2020

Computed Tomography to Cone Beam Computed Tomography Deformable Image Registration for Contour Propagation Using Head and Neck, Patient-Based Computational Phantoms: A Multicenter Study.

Pract Radiat Oncol 2020 Mar - Apr;10(2):125-132. Epub 2019 Nov 28.

University of Turin, Department of Oncology, Turin, Italy; School of Bioengineering and Medical-Surgical Sciences, Politecnico di Torino, Turin, Italy.

Purpose: To investigate the performance of various algorithms for deformable image registration (DIR) for propagating regions of interest (ROIs) using multiple commercial platforms, from computed tomography to cone beam computed tomography (CBCT) and megavoltage computed tomography.

Methods And Materials: Fourteen institutions participated in the study using 5 commercial platforms: RayStation (RaySearch Laboratories, Stockholm, Sweden), MIM (Cleveland, OH), VelocityAI and SmartAdapt (Varian Medical Systems, Palo Alto, CA), and ABAS (Elekta AB, Stockholm, Sweden). Algorithms were tested on synthetic images generated with the ImSimQA (Oncology Systems Limited, Shrewsbury, UK) package by applying 2 specific deformation vector fields (DVF) to real head and neck patient datasets. On-board images from 3 systems were used: megavoltage computed tomography from Tomotherapy and 2 kinds of CBCT from a clinical linear accelerator. Image quality of the system was evaluated. The algorithms' accuracy was assessed by comparing the DIR-mapped ROIs returned by each center with those of the reference, using the Dice similarity coefficient and mean distance to conformity metrics. Statistical inference on the validation results was carried out to identify the prognostic factors of DIR performance.

Results: Analyzing 840 DIR-mapped ROIs returned by the centers, it was demonstrated that DVF intensity and image quality were significant prognostic factors of DIR performance. The accuracy of the propagated contours was generally high, and acceptable DIR performance can be obtained with lower-dose CBCT image protocols.

Conclusions: The performance of the systems proved to be image quality specific, depending on the DVF type and only partially on the platforms. All systems proved to be robust against image artifacts and noise, except the demon-based software.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.prro.2019.11.011DOI Listing
October 2020

Performance of commercially available deformable image registration platforms for contour propagation using patient-based computational phantoms: A multi-institutional study.

Med Phys 2018 Feb 9;45(2):748-757. Epub 2018 Jan 9.

Department of Oncology, University of Turin, Turin, Italy.

Purpose: To investigate the performance of various algorithms for deformable image registration (DIR) to propagate regions of interest (ROIs) using multiple commercial platforms.

Methods And Materials: Thirteen institutions participated in the study with six commercial platforms: RayStation (RaySearch Laboratories, Stockholm, Sweden), MIM (Cleveland, OH, USA), VelocityAI and Smart Adapt (Varian Medical Systems, Palo Alto, CA, USA), Mirada XD (Mirada Medical Ltd, Oxford, UK), and ABAS (Elekta AB, Stockholm, Sweden). The DIR algorithms were tested on synthetic images generated with the ImSimQA package (Oncology Systems Limited, Shrewsbury, UK) by applying two specific Deformation Vector Fields (DVF) to real patient data-sets. Head-and-neck (HN), thorax, and pelvis sites were included. The accuracy of the algorithms was assessed by comparing the DIR-mapped ROIs from each center with those of reference, using the Dice Similarity Coefficient (DSC) and Mean Distance to Conformity (MDC) metrics. Statistical inference on validation results was carried out in order to identify the prognostic factors of DIR performances.

Results: DVF intensity, anatomic site and participating center were significant prognostic factors of DIR performances. Sub-voxel accuracy was obtained in the HN by all algorithms. Large errors, with MDC ranging up to 6 mm, were observed in low-contrast regions that underwent significant deformation, such as in the pelvis, or large DVF with strong contrast, such as the clinical tumor volume (CTV) in the lung. Under these conditions, the hybrid DIR algorithms performed significantly better than the free-form intensity based algorithms and resulted robust against intercenter variability.

Conclusions: The performances of the systems proved to be site specific, depending on the DVF type and the platforms and the procedures used at the various centers. The pelvis was the most challenging site for most of the algorithms, which failed to achieve sub-voxel accuracy. Improved reproducibility was observed among the centers using the same hybrid registration algorithm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/mp.12737DOI Listing
February 2018

MR Spectroscopy in Prostate Cancer: New Algorithms to Optimize Metabolite Quantification.

PLoS One 2016 10;11(11):e0165730. Epub 2016 Nov 10.

Medical Physics Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy.

Prostate cancer (PCa) is the most common non-cutaneous cancer in male subjects and the second leading cause of cancer-related death in developed countries. The necessity of a non-invasive technique for the diagnosis of PCa in early stage has grown through years. Proton magnetic resonance spectroscopy (1H-MRS) and proton magnetic resonance spectroscopy imaging (1H-MRSI) are advanced magnetic resonance techniques that can mark the presence of metabolites such as citrate, choline, creatine and polyamines in a selected voxel, or in an array of voxels (in MRSI) inside prostatic tissue. Abundance or lack of these metabolites can discriminate between pathological and healthy tissue. Although the use of magnetic resonance spectroscopy (MRS) is well established in brain and liver with dedicated software for spectral analysis, quantification of metabolites in prostate can be very difficult to achieve, due to poor signal to noise ratio and strong J-coupling of the citrate. The aim of this work is to develop a software prototype for automatic quantification of citrate, choline and creatine in prostate. Its core is an original fitting routine that makes use of a fixed step gradient descent minimization algorithm (FSGD) and MRS simulations developed with the GAMMA libraries in C++. The accurate simulation of the citrate spin systems allows to predict the correct J-modulation under different NMR sequences and under different coupling parameters. The accuracy of the quantifications was tested on measurements performed on a Philips Ingenia 3T scanner using homemade phantoms. Some acquisitions in healthy volunteers have been also carried out to test the software performance in vivo.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0165730PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5104319PMC
June 2017

Lung stereotactic ablative body radiotherapy: A large scale multi-institutional planning comparison for interpreting results of multi-institutional studies.

Phys Med 2016 Apr 6;32(4):600-6. Epub 2016 Apr 6.

AUSL Piacenza, Italy.

Purpose: A large-scale multi-institutional planning comparison on lung cancer SABR is presented with the aim of investigating possible criticism in carrying out retrospective multicentre data analysis from a dosimetric perspective.

Methods: Five CT series were sent to the participants. The dose prescription to PTV was 54Gy in 3 fractions of 18Gy. The plans were compared in terms of PTV-gEUD2 (generalized Equivalent Uniform Dose equivalent to 2Gy), mean dose to PTV, Homogeneity Index (PTV-HI), Conformity Index (PTV-CI) and Gradient Index (PTV-GI). We calculated the maximum dose for each OAR (organ at risk) considered as well as the MLD2 (mean lung dose equivalent to 2Gy). The data were stratified according to expertise and technology.

Results: Twenty-six centers equipped with Linacs, 3DCRT (4% - 1 center), static IMRT (8% - 2 centers), VMAT (76% - 20 centers), CyberKnife (4% - 1 center), and Tomotherapy (8% - 2 centers) collaborated. Significant PTV-gEUD2 differences were observed (range: 105-161Gy); mean-PTV dose, PTV-HI, PTV-CI, and PTV-GI were, respectively, 56.8±3.4Gy, 14.2±10.1%, 0.70±0.15, and 4.9±1.9. Significant correlations for PTV-gEUD2 versus PTV-HI, and MLD2 versus PTV-GI, were observed.

Conclusions: The differences in terms of PTV-gEUD2 may suggest the inclusion of PTV-gEUD2 calculation for retrospective data inter-comparison.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2016.03.015DOI Listing
April 2016

Preliminary Retrospective Analysis of Daily Tomotherapy Output Constancy Checks Using Statistical Process Control.

PLoS One 2016 5;11(2):e0147936. Epub 2016 Feb 5.

Medical Physics Department, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, FC, Italy.

The purpose of this study was to retrospectively evaluate the results from a Helical TomoTherapy Hi-Art treatment system relating to quality controls based on daily static and dynamic output checks using statistical process control methods. Individual value X-charts, exponentially weighted moving average charts, and process capability and acceptability indices were used to monitor the treatment system performance. Daily output values measured from January 2014 to January 2015 were considered. The results obtained showed that, although the process was in control, there was an out-of-control situation in the principal maintenance intervention for the treatment system. In particular, process capability indices showed a decreasing percentage of points in control which was, however, acceptable according to AAPM TG148 guidelines. Our findings underline the importance of restricting the acceptable range of daily output checks and suggest a future line of investigation for a detailed process control of daily output checks for the Helical TomoTherapy Hi-Art treatment system.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0147936PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4746057PMC
July 2016

Efficacy of different sequences of radio- and chemotherapy in experimental models of human melanoma.

J Cell Physiol 2014 Oct;229(10):1548-56

Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Italy.

Although combination chemotherapy and radiotherapy have become the standard of care in numerous tumors, the mechanisms of interaction are often still unclear. The purpose of this study was to analyze the efficacy of radiation treatment and cisplatin sequences and to investigate their mechanisms of interaction. Three melanoma cell lines were used to evaluate in vitro radiation-induced cytotoxicity before and after cisplatin treatment. Expression levels of a panel of genes were determined by real-time RT-PCR. Cytotoxic effect was evaluated by flow cytometry analysis and Comet assay. We also used normal human dermal fibroblasts (HUDE) to evaluate the cytotoxicity of the two treatments by clonogenic assay. Radiation and cisplatin used singly were not particularly effective in reducing proliferation in melanoma cells. Conversely, radiation treatment followed by cisplatin showed a strong synergistic interaction in all cell lines, with a ratio index ranging from 16 to >100. The synergistic effect was accompanied by apoptosis induction (up to 40%) and an increase in the percentage of comet-shaped nucleoids from 85% to 99%. In parallel, our results also showed that radiation treatment of HUDE fibroblasts followed by cisplatin only induced weak cytotoxicity. Our findings highlight the efficacy of the sequence radiation → cisplatin in reducing cell proliferation and in inducing apoptosis in melanoma cell lines. This sequence also modulated a network of proteins involved in DNA damage repair.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jcp.24598DOI Listing
October 2014

In vitro irradiation system for radiobiological experiments.

Radiat Oncol 2013 Nov 1;8:257. Epub 2013 Nov 1.

Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Biosciences Laboratory, via P, Maroncelli 40, 47014, Meldola, FC, Italy.

Background: Although two-dimensional (2-D) monolayer cell cultures provide important information on basic tumor biology and radiobiology, they are not representative of the complexity of three-dimensional (3-D) solid tumors. In particular, new models reproducing clinical conditions as closely as possible are needed for radiobiological studies to provide information that can be translated from bench to bedside.

Methods: We developed a novel system for the irradiation, under sterile conditions, of 3-D tumor spheroids, the in vitro model considered as a bridge between the complex architectural organization of in vivo tumors and the very simple one of in vitro monolayer cell cultures. The system exploits the same equipment as that used for patient treatments, without the need for dedicated and highly expensive instruments. To mimic the passage of radiation beams through human tissues before they reach the target tumor mass, 96-multiwell plates containing the multicellular tumor spheroids (MCTS) are inserted into a custom-built phantom made of plexiglass, the material most similar to water, the main component of human tissue.

Results: The system was used to irradiate CAEP- and A549-derived MCTS, pre-treated or not with 20 μM cisplatin, with a dose of 20 Gy delivered in one session. We also tested the same treatment schemes on monolayer CAEP and A549 cells. Our preliminary results indicated a significant increment in radiotoxicity 20 days after the end of irradiation in the CAEP spheroids pre-treated with cisplatin compared to those treated with cisplatin or irradiation alone. Conversely, the effect of the radio- chemotherapy combination in A549-derived MCTS was similar to that induced by cisplatin or irradiation alone. Finally, the 20 Gy dose did not affect cell survival in monolayer CAEP and A549 cells, whereas cisplatin or cisplatin plus radiation caused 100% cell death, regardless of the type of cell line used.

Conclusions: We set up a system for the irradiation, under sterile conditions, of tumor cells grown in 3-D which allows for the use of the same dose intensities and schedules utilized in clinical practice. This irradiation system, coupled with 3-D cell cultures, has the potential to generate information that could be used to individually tailor radiotherapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/1748-717X-8-257DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3874638PMC
November 2013

SLUG silencing increases radiosensitivity of melanoma cells in vitro.

Cell Oncol (Dordr) 2013 Apr 19;36(2):131-9. Epub 2012 Dec 19.

Biosciences Laboratory, IRCCS Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), Via P. Maroncelli 40, Meldola, 47014, Italy.

Background: Melanoma radioresistance has been attributed to the presence of tumor cells with highly efficient DNA damage repair mechanisms. We examined the expression of genes involved in DNA damage repair and DNA damage sensing, and assessed their modulation by SLUG silencing, which is potentially capable of increasing radiosensitivity.

Methods: Two melanoma cell lines (M14 and M79) were used to evaluate in vitro radiation-induced cytotoxicity before and after SLUG silencing. mRNA expression levels of BRCA1, ERCC1, DNA-PK, PARP, MGMT, ATM and TGM2 were determined by real-time RT-PCR, and protein expression levels of SLUG, caspase 3, p21, PUMA and pMAPK by Western blotting.

Results: The cytotoxic effect of radiation was high in M14 and low in M79 cells. SLUG silencing increased the interference of radiation on cell cycle distribution and cell killing by 60 % and 80 % in M79 cells after a 2.4 Gy and 5 Gy radiation dose, respectively. It also led to a significant inhibition of expression of genes involved in DNA damage repair and DNA damage sensing in all cell lines maintained after radiation. An almost total inhibition was observed for TGM2, which is expressed at a high basal level in the most radioresistant cell line (M79). Protein expression of PUMA was induced by radiation and was enhanced after SLUG silencing.

Conclusions: Our results reveal a pivotal role of SLUG in regulating a cellular network involved in the response to DNA damage, and highlight the importance of TGM2 in radiosensitivity modulation. SLUG silencing appears to increase radiation sensitivity of the melanoma cells tested.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s13402-012-0120-6DOI Listing
April 2013

Monte Carlo dose voxel kernel calculations of beta-emitting and Auger-emitting radionuclides for internal dosimetry: A comparison between EGSnrcMP and EGS4.

Med Phys 2006 Sep;33(9):3383-9

Laboratory of Medical Physics and Expert Systems, National Cancer Institute Regina Elena, Rome, 00144 Italy.

Dose-point kernels (DPKs) can be widely applied to therapeutic nuclear medicine to obtain more accurate absorbed dose assessments in internal dosimetry assuming a spherical geometry. Recently, EGSnrc-the latest in the family of EGS Monte Carlo codes--has been tested for isotropic monoenergetic electrons and Y-90 beta spectrum in spherical geometry. The availability of SPECT images allows one to take into account heterogeneities in activity distribution within tumors, and to perform dose calculations using voxel dosimetry based on Monte Carlo simulations in a Cartesian geometry. The purpose of this study is to evaluate the differences of dose distributions scored in Cartesian voxels also known as Dose Voxel Kernels (DVKs) for five beta-emitting (131I, 89Sr, 153Sm, 186Re, and 90Y) and Auger-emitting (111In) radionuclides, when their computation is made using these two Monte Carlo codes from the same family to check if the new physics in EGSnrc simulation system produces DVK very different from those calculated with EGS4. We have calculated the DVKs for point and voxel sources in Cartesian scoring grids of different spatial resolutions. Our results for the point source, scored in the finer spatial resolution, show a poor agreement between EGSnrc and EGS4 (up to about 20%) for voxels closer to the origin, and a better agreement (below 5%) for longer distances for all radionuclides. For the voxel source, where doses were scored in the coarser spatial resolution, dose deposition in the central voxel is in good agreement for all the radionuclides; while surrounding voxels exhibit a slightly worse agreement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1118/1.2266255DOI Listing
September 2006
-->