Publications by authors named "Mario Marengo"

31 Publications

In vitro thrombogenicity of drug-eluting and bare metal stents.

Thromb Res 2020 01 14;185:43-48. Epub 2019 Nov 14.

Columbia University Medical Center/New York-Presbyterian Hospital and the Cardiovascular Research Foundation, New York, NY, United States.

Aims: We sought to investigate the thrombogenicity of different DES and BMS in an in vitro system of stent perfusion.

Material And Methods: The experimental model consisted of a peristaltic pump connected to 4 parallel silicone tubes in which different stents were deployed. Blood was drawn from healthy volunteers and the amount of stent surfaced-induced thrombus deposition was determined using I-fibrinogen.

Results: Compared to Resolute, Biomatrix and Vision, Xience was associated with the lowest amount of stent surface-induced thrombus formation, with a significant difference compared to Vision (I-fibrinogen median value deposition [IQ range]: 50 ng [25-98] versus 560 ng [320-1520], respectively, p < 0.05), but not to other DES. In the second set of experiments Fluoropolymer-coated BMS not eluting drug was associated with a significant 3-fold reduction in I-fibrinogen deposition (245 ng [80-300]) compared to Vision (625 ng [320-760], p < 0.05), but a 7-fold increase compared to Xience (35 ng [20-60], p < 0.05). Finally Xience was associated with a significantly greater absorption of albumin compared to BMS.

Conclusions: In an in vitro system of stent perfusion, Xience was associated with the lowest amount of stent surface-induced thrombus formation compared with Resolute, Biomatrix and Vision, with a noted synergistic effect between the fluoropolymer and the drug.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.thromres.2019.11.016DOI Listing
January 2020

Innovative Target for Production of Technetium-99m by Biomedical Cyclotron.

Molecules 2018 Dec 21;24(1). Epub 2018 Dec 21.

Legnaro National Laboratories, Italian National Institute for Nuclear Physics (LNL-INFN), Viale dell'Università 2, 35020 Legnaro PD, Italy.

Technetium-99m (Tc) is the most used radionuclide worldwide in nuclear medicine for diagnostic imaging procedures. Tc is typically extracted from portable generators containing Mo, which is produced normally in nuclear reactors as a fission product of highly enriched Uranium material. Due to unexpected outages or planned and unplanned reactor shutdown, significant Tc shortages appeared as a problem since 2008 The alternative cyclotron-based approach through the Mo(p,2n)Tc reaction is considered one of the most promising routes for direct Tc production in order to mitigate potential Mo shortages. The design and manufacturing of appropriate cyclotron targets for the production of significant amounts of a radiopharmaceutical for medical use is a technological challenge. In this work, a novel solid target preparation method was developed, including sputter deposition of a dense, adherent, and non-oxidized Mo target material onto a complex backing plate. The latter included either chemically resistant sapphire or synthetic diamond brazed in vacuum conditions to copper. The target thermo-mechanical stability tests were performed under 15.6 MeV proton energy and different beam intensities, up to the maximum provided by the available GE Healthcare (Chicago, IL, USA) PET trace medical cyclotron. The targets resisted proton beam currents up to 60 µA (corresponding to a heat power density of about 1 kW/cm²) without damage or Mo deposited layer delamination. The chemical stability of the proposed backing materials was proven by gamma-spectroscopy analysis of the solution obtained after the standard dissolution procedure of irradiated targets in H₂O₂.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/molecules24010025DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6337538PMC
December 2018

Production of Ga-68 with a General Electric PETtrace cyclotron by liquid target.

Phys Med 2018 Nov 25;55:116-126. Epub 2018 Oct 25.

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

Purpose: In recent years the use of Ga (t = 67.84 min, β: 88.88%) for the labelling of different PET radiopharmaceuticals has significantly increased. This work aims to evaluate the feasibility of the production of Ga via the Zn(p,n)Ga reaction by proton irradiation of an enriched zinc solution, using a biomedical cyclotron, in order to satisfy its increasing demand.

Methods: Irradiations of 1.7 Msolution of Zn(NO) in 0.2 N HNO were conducted with a GE PETtrace cyclotron using a slightly modified version of the liquid target used for the production of fluorine-18. The proton beam energy was degraded to 12 MeV, in order to minimize the production of Ga through theZn(p,2n)Ga reaction. The product's activity was measured using a calibrated activity meter and a High Purity Germanium gamma-ray detector.

Results: The saturation yield ofGa amounts to (330 ± 20) MBq/µA, corresponding to a produced activity ofGa at the EOB of (4.3 ± 0.3) GBq in a typical production run at 46 µA for 32 min. The radionuclidic purity of theGa in the final product, after the separation, is within the limits of the European Pharmacopoeia (>99.9%) up to 3 h after the EOB. Radiochemical separation up to a yield not lower than 75% was obtained using an automated purification module. The enriched material recovery efficiency resulted higher than 80-90%.

Conclusions: In summary, this approach provides clinically relevant amounts ofGa by cyclotron irradiation of a liquid target, as a competitive alternative to the current production through theGe/Ga generators.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2018.10.018DOI Listing
November 2018

In-house cyclotron production of high-purity Tc-99m and Tc-99m radiopharmaceuticals.

Appl Radiat Isot 2018 Sep 30;139:325-331. Epub 2018 May 30.

Legnaro Laboratories, Italian National Institute for Nuclear Physics (INFN), Legnaro, Padua, Italy; Department of Chemical and Pharmaceutical Sciences, University of Ferrara, Ferrara, Italy.

In the last years, the technology for producing the important medical radionuclide technetium-99m by cyclotrons has become sufficiently mature to justify its introduction as an alternative source of the starting precursor [Tc][TcO] ubiquitously employed for the production of Tc-radiopharmaceuticals in hospitals. These technologies make use almost exclusively of the nuclear reaction Mo(p,2n)Tc that allows direct production of Tc-99m. In this study, it is conjectured that this alternative production route will not replace the current supply chain based on the distribution of Mo/Tc generators, but could become a convenient emergency source of Tc-99m only for in-house hospitals equipped with a conventional, low-energy, medical cyclotron. On this ground, an outline of the essential steps that should be implemented for setting up a hospital radiopharmacy aimed at the occasional production of Tc-99m by a small cyclotron is discussed. These include (1) target production, (2) irradiation conditions, (3) separation/purification procedures, (4) terminal sterilization, (5) quality control, and (6) Mo-100 recovery. To address these issues, a comprehensive technology for cyclotron-production of Tc-99m, developed at the Legnaro National Laboratories of the Italian National Institute of Nuclear Physics (LNL-INFN), will be used as a reference example.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.apradiso.2018.05.033DOI Listing
September 2018

Modeling of a Cyclotron Target for the Production of 11C with Geant4.

Curr Radiopharm 2018 ;11(2):92-99

Medical Physics Unit, University Hospital "S. Orsola-Malpighi", Via Massarenti 9, 40138, Bologna, Italy.

Background: In medical cyclotron facilities, 11C is produced according to the 14N(p,α)11C reaction and widely employed in studies of prostate and brain cancers by Positron Emission Tomography. It is known from literature that the 11C-target assembly shows a reduction in efficiency during time, meaning a decrease of activity produced at the end of bombardment. This effect might depend on aspects which are still not completely known.

Objective: Possible causes of the loss of performance of the 11C-target assembly were addressed by Monte Carlo simulations.

Methods: Geant4 was used to model the 11C-target assembly of a GE PETtrace cyclotron. The physical and transport parameters to be used in the energy range of medical applications were extracted from literature data and 11C routine productions. The Monte Carlo assessment of 11C saturation yield was performed varying several parameters such as the proton energy and the angle of the target assembly with respect to the proton beam.

Results: The estimated 11C saturation yield is in agreement with IAEA data at the energy of interest, while it is about 35% greater than the experimental value. A more comprehensive modeling of the target system, including thermodynamic effect, is required. The energy absorbed in the inner layer of the target chamber was up to 46.5 J/mm2 under typical irradiation conditions.

Conclusion: This study shows that Geant4 is potentially a useful tool to design and optimize targetry for PET radionuclide productions. Tests to choose the Geant4 physics libraries should be performed before using this tool with different energies and materials.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2174/1874471011666180412170219DOI Listing
October 2018

Implementation of Quality Systems in Nuclear Medicine: Why It Matters. An Outcome Analysis (Quality Management Audits in Nuclear Medicine Part III).

Semin Nucl Med 2018 05 9;48(3):299-306. Epub 2018 Feb 9.

Nuclear Medicine and Diagnostic Imaging Section, Division of Human Health; IAEA, Vienna, Austria.

The International Atomic Energy Agency (IAEA) developed a comprehensive program-Quality Management Audits in Nuclear Medicine (QUANUM). This program covers all aspects of nuclear medicine practices including, but not limited to, clinical practice, management, operations, and services. The QUANUM program, which includes quality standards detailed in relevant checklists, aims at introducing a culture of comprehensive quality audit processes that are patient oriented, systematic, and outcome based. This paper will focus on the impact of the implementation of QUANUM on daily routine practices in audited centers. Thirty-seven centers, which had been externally audited by experts under IAEA auspices at least 1 year earlier, were invited to run an internal audit using the QUANUM checklists. The external audits also served as training in quality management and the use of QUANUM for the local teams, which were responsible of conducting the internal audits. Twenty-five out of the 37 centers provided their internal audit report, which was compared with the previous external audit. The program requires that auditors score each requirement within the QUANUM checklists on a scale of 0-4, where 0-2 means nonconformance and 3-4 means conformance to international regulations and standards on which QUANUM is based. Our analysis covering both general and clinical areas assessed changes on the conformance status on a binary manner and the level of conformance scores. Statistical analysis was performed using nonparametric statistical tests. The evaluation of the general checklists showed a global improvement on both the status and the levels of conformances (P < 0.01). The evaluation of the requirements by checklist also showed a significant improvement in all, with the exception of Hormones and Tumor marker determinations, where changes were not significant. Of the 25 evaluated institutions, 88% (22 of 25) and 92% (23 of 25) improved their status and levels of conformance, respectively. Fifty-five requirements, on average, increased from nonconformance to conformance status. In 8 key areas, the number of improved requirements was well above the average: Administration & Management (checklist 2); Radiation Protection & Safety (checklist 4); General Quality Assurance system (checklist 6); Imaging Equipment Quality Assurance or Quality Control (checklist 7); General Diagnostic (checklist 9); General Therapeutic (checklist 12); Radiopharmacy Level 1 (checklist 14); and Radiopharmacy Level 2 (checklist 15). Analysis of results related to clinical activities showed an overall positive impact on both the status and the level of conformance to international standards. Similar results were obtained for the most frequently performed clinical imaging and therapeutic procedures. Our study shows that the implementation of a comprehensive quality management system through the IAEA QUANUM program has a positive impact on nuclear medicine practices.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.semnuclmed.2017.12.001DOI Listing
May 2018

Comprehensive Auditing in Nuclear Medicine Through the International Atomic Energy Agency Quality Management Audits in Nuclear Medicine Program. Part 2: Analysis of Results.

Semin Nucl Med 2017 11 27;47(6):687-693. Epub 2017 Jul 27.

Nuclear Medicine and Diagnostic Imaging Section, Division of Human Health, IAEA, Vienna, Austria.

The International Atomic Energy Agency has developed a program, named Quality Management Audits in Nuclear Medicine (QUANUM), to help its Member States to check the status of their nuclear medicine practices and their adherence to international reference standards, covering all aspects of nuclear medicine, including quality assurance/quality control of instrumentation, radiopharmacy (further subdivided into levels 1, 2, and 3, according to complexity of work), radiation safety, clinical applications, as well as managerial aspects. The QUANUM program is based on both internal and external audits and, with specifically developed Excel spreadsheets, it helps assess the level of conformance (LoC) to those previously defined quality standards. According to their level of implementation, the level of conformance to requested standards; 0 (absent) up to 4 (full conformance). Items scored 0, 1, and 2 are considered non-conformance; items scored 3 and 4 are considered conformance. To assess results of the audit missions performed worldwide over the last 8 years, a retrospective analysis has been run on reports from a total of 42 audit missions in 39 centers, three of which had been re-audited. The analysis of all audit reports has shown an overall LoC of 73.9 ± 8.3% (mean ± standard deviation), ranging between 56.6% and 87.9%. The highest LoC has been found in the area of clinical services (83.7% for imaging and 87.9% for therapy), whereas the lowest levels have been found for Radiopharmacy Level 2 (56.6%); Computer Systems and Data Handling (66.6%); and Evaluation of the Quality Management System (67.6%). Prioritization of non-conformances produced a total of 1687 recommendations in the final audit report. Depending on the impact on safety and daily clinical activities, they were further classified as critical (requiring immediate action; n = 276; 16% of the total); major (requiring action in relatively short time, typically from 3 to 6 months; n = 604; 36%); whereas the remaining 807 (48%) were classified as minor, that is, to be addressed whenever possible. The greatest proportion of recommendations has been found in the category "Managerial, Organization and Documentation" (26%); "Staff Radiation Protection and Safety" (17.3%); "Radiopharmaceuticals Preparation, Dispensing and Handling" (15.8%); and "Quality Assurance/Quality Control" and "Management of Equipment and Software" (11.4%). The lowest level of recommendations belongs to the item "Human Resources" (4%). The QUANUM program proved applicable to a wide variety of institutions, from small practices to larger centers with PET/CT and cyclotrons. Clinical services rendered to patients showed a good compliance with international standards, whereas issues related to radiation protection of both staff and patients will require a higher degree of attention. This is a relevant feedback for the International Atomic Energy Agency with regard to the effective translation of safety recommendations into routine practice. Training on drafting and application of standard operating procedures should also be considered a priority.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.semnuclmed.2017.07.004DOI Listing
November 2017

Comprehensive Auditing in Nuclear Medicine Through the International Atomic Energy Agency Quality Management Audits in Nuclear Medicine (QUANUM) Program. Part 1: the QUANUM Program and Methodology.

Semin Nucl Med 2017 11 25;47(6):680-686. Epub 2017 Jul 25.

Nuclear Medicine and Diagnostic Imaging Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria.

An effective management system that integrates quality management is essential for a modern nuclear medicine practice. The Nuclear Medicine and Diagnostic Imaging Section of the International Atomic Energy Agency (IAEA) has the mission of supporting nuclear medicine practice in low- and middle-income countries and of helping them introduce it in their health-care system, when not yet present. The experience gathered over several years has shown diversified levels of development and varying degrees of quality of practice, among others because of limited professional networking and limited or no opportunities for exchange of experiences. Those findings triggered the development of a program named Quality Management Audits in Nuclear Medicine (QUANUM), aimed at improving the standards of NM practice in low- and middle-income countries to internationally accepted standards through the introduction of a culture of quality management and systematic auditing programs. QUANUM takes into account the diversity of nuclear medicine services around the world and multidisciplinary contributions to the practice. Those contributions include clinical, technical, radiopharmaceutical, and medical physics procedures. Aspects of radiation safety and patient protection are also integral to the process. Such an approach ensures consistency in providing safe services of superior quality to patients. The level of conformance is assessed using standards based on publications of the IAEA and the International Commission on Radiological Protection, and guidelines from scientific societies such as Society of Nuclear Medicine and Molecular Imaging (SNMMI) and European Association of Nuclear Medicine (EANM). Following QUANUM guidelines and by means of a specific assessment tool developed by the IAEA, auditors, both internal and external, will be able to evaluate the level of conformance. Nonconformances will then be prioritized and recommendations will be provided during an exit briefing. The same tool could then be applied to assess any improvement after corrective actions are taken. This is the first comprehensive audit program in nuclear medicine that helps evaluate managerial aspects, safety of patients and workers, clinical practice, and radiopharmacy, and, above all, keeps them under control all together, with the intention of continuous improvement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1053/j.semnuclmed.2017.07.003DOI Listing
November 2017

Assessment of the neutron dose field around a biomedical cyclotron: FLUKA simulation and experimental measurements.

Phys Med 2016 Dec 3;32(12):1602-1608. Epub 2016 Dec 3.

Medical Physics Department, University Hospital "S. Orsola-Malpighi", Via Massarenti 9, 40138 Bologna, Italy.

In the planning of a new cyclotron facility, an accurate knowledge of the radiation field around the accelerator is fundamental for the design of shielding, the protection of workers, the general public and the environment. Monte Carlo simulations can be very useful in this process, and their use is constantly increasing. However, few data have been published so far as regards the proper validation of Monte Carlo simulation against experimental measurements, particularly in the energy range of biomedical cyclotrons. In this work a detailed model of an existing installation of a GE PETtrace 16.5MeV cyclotron was developed using FLUKA. An extensive measurement campaign of the neutron ambient dose equivalent H(10) in marked positions around the cyclotron was conducted using a neutron rem-counter probe and CR39 neutron detectors. Data from a previous measurement campaign performed by our group using TLDs were also re-evaluated. The FLUKA model was then validated by comparing the results of high-statistics simulations with experimental data. In 10 out of 12 measurement locations, FLUKA simulations were in agreement within uncertainties with all the three different sets of experimental data; in the remaining 2 positions, the agreement was with 2/3 of the measurements. Our work allows to quantitatively validate our FLUKA simulation setup and confirms that Monte Carlo technique can produce accurate results in the energy range of biomedical cyclotrons.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2016.11.115DOI Listing
December 2016

Radiation Protection Studies for Medical Particle Accelerators using Fluka Monte Carlo Code.

Radiat Prot Dosimetry 2017 Apr;173(1-3):185-191

Medical Physics Department, S. Orsola-Malpighi University Hospital, Via Massarenti 9, 40138 Bologna, Italy.

Radiation protection (RP) in the use of medical cyclotrons involves many aspects both in the routine use and for the decommissioning of a site. Guidelines for site planning and installation, as well as for RP assessment, are given in international documents; however, the latter typically offer analytic methods of calculation of shielding and materials activation, in approximate or idealised geometry set-ups. The availability of Monte Carlo (MC) codes with accurate up-to-date libraries for transport and interaction of neutrons and charged particles at energies below 250 MeV, together with the continuously increasing power of modern computers, makes the systematic use of simulations with realistic geometries possible, yielding equipment and site-specific evaluation of the source terms, shielding requirements and all quantities relevant to RP at the same time. In this work, the well-known FLUKA MC code was used to simulate different aspects of RP in the use of biomedical accelerators, particularly for the production of medical radioisotopes. In the context of the Young Professionals Award, held at the IRPA 14 conference, only a part of the complete work is presented. In particular, the simulation of the GE PETtrace cyclotron (16.5 MeV) installed at S. Orsola-Malpighi University Hospital evaluated the effective dose distribution around the equipment; the effective number of neutrons produced per incident proton and their spectral distribution; the activation of the structure of the cyclotron and the vault walls; the activation of the ambient air, in particular the production of 41Ar. The simulations were validated, in terms of physical and transport parameters to be used at the energy range of interest, through an extensive measurement campaign of the neutron environmental dose equivalent using a rem-counter and TLD dosemeters. The validated model was then used in the design and the licensing request of a new Positron Emission Tomography facility.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/rpd/ncw302DOI Listing
April 2017

A solvent-extraction module for cyclotron production of high-purity technetium-99m.

Appl Radiat Isot 2016 Dec 5;118:302-307. Epub 2016 Oct 5.

Legnaro National Laboratories, Italian National Institute for Nuclear Physics (LNL-INFN), Italy.

The design and fabrication of a fully-automated, remotely controlled module for the extraction and purification of technetium-99m (Tc-99m), produced by proton bombardment of enriched Mo-100 molybdenum metallic targets in a low-energy medical cyclotron, is here described. After dissolution of the irradiated solid target in hydrogen peroxide, Tc-99m was obtained under the chemical form of TcO, in high radionuclidic and radiochemical purity, by solvent extraction with methyl ethyl ketone (MEK). The extraction process was accomplished inside a glass column-shaped vial especially designed to allow for an easy automation of the whole procedure. Recovery yields were always >90% of the loaded activity. The final pertechnetate saline solution NaTcO, purified using the automated module here described, is within the Pharmacopoeia quality control parameters and is therefore a valid alternative to generator-produced Tc. The resulting automated module is cost-effective and easily replicable for in-house production of high-purity Tc-99m by cyclotrons.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.apradiso.2016.10.002DOI Listing
December 2016

Presurgical assessment of a melanoma during pregnancy based on dermoscopy and confocal laser microscopy.

G Ital Dermatol Venereol 2016 Aug;151(4):445-6

Skin Cancer Unit, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST), IRCCS, Meldola, Forlì-Cesena, Italy -

View Article and Find Full Text PDF

Download full-text PDF

Source
August 2016

Experimental measurement and Monte Carlo assessment of Argon-41 production in a PET cyclotron facility.

Phys Med 2015 Dec 26;31(8):991-996. Epub 2015 Sep 26.

Medical Physics Department, University Hospital "S. Orsola-Malpighi", Via Massarenti 9, 40138, Bologna, Italy.

In a medical cyclotron facility, (41)Ar (t1/2 = 109.34 m) is produced by the activation of air due to the neutron flux during irradiation, according to the (40)Ar(n,γ)(41)Ar reaction; this is particularly relevant in widely diffused high beam current cyclotrons for the production of PET radionuclides. While theoretical estimations of the (41)Ar production have been published, no data are available on direct experimental measurements for a biomedical cyclotron. In this work, we describe a sampling methodology and report the results of an extensive measurement campaign. Furthermore, the experimental results are compared with Monte Carlo simulations performed with the FLUKA code. To measure (41)Ar activity, air samples were taken inside the cyclotron bunker in sealed Marinelli beakers, during the routine production of (18)F with a 16.5 MeV GE-PETtrace cyclotron; this sampling thus reproduces a situation of absence of air changes. Samples analysis was performed in a gamma-ray spectrometry system equipped with HPGe detector. Monte Carlo assessment of the (41)Ar saturation yield was performed directly using the standard FLUKA score RESNUCLE, and off-line by the convolution of neutron fluence with cross section data. The average (41)Ar saturation yield per one liter of air of (41)Ar, measured in gamma-ray spectrometry, resulted to be 3.0 ± 0.6 Bq/µA*dm(3) while simulations gave a result of 6.9 ± 0.3 Bq/µA*dm(3) in the direct assessment and 6.92 ± 0.22 Bq/µA*dm(3) by the convolution neutron fluence-to-cross section.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejmp.2015.07.146DOI Listing
December 2015

Generator breakthrough and radionuclidic purification in automated synthesis of 68Ga-DOTANOC.

Curr Radiopharm 2013 Jun;6(2):72-7

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

68Ga labeled radiopharmaceuticals, like 68Ga-DOATNOC and other similar peptides, are gaining relevance in PET-CT, thanks to relatively easy local generator production, that do not requires an installed cyclotron. However, generator produced 68Ga is typically of suboptimal purity, mainly due to the breakthrough of the parent radionuclide 68Ge. Modern automated synthesis modules adopt both fractionation methods and purification methods in order to get rid of 68Ge breakthrough. Purification methods are mainly based on based on cationic prepurification even if anionic purification has been adopted as well. This work studies the efficacy of cationic prepurification using commercial STRATA-X-C, as well as distribution of the 68Ge contaminant during all steps of the synthesis of labeled peptides. Generator waste, STRATA-X-C purification cartridge, synthesis waste and the final product are quantitatively analyzed by means of high resolution gamma ray spectrometry. Our results show that current method of purification is highly effective; initial 68Ge breakthrough of the order of 1 kBq is decreased by a factor greater than 100, with removal of about 61% of the contaminant 68Ge in the first purification passage; this allow an efficient labeling, since removal of the remaining impurity happens during chelation in the reactor vessel. In conclusion, the synthesis with modular automated system resulted to reliably produce 68Ga-DOTANOC, with limited if any user intervention. 68Ge content in the final formulation results lower than 2x10(-7)%, avoiding unjustified patient irradiation due to radionuclidic impurities and satisfying quality prerequisites for radiopharmaceutical preparations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2174/1874471011306020002DOI Listing
June 2013

Attenuation correction for small animal PET images: a comparison of two methods.

Comput Math Methods Med 2013 16;2013:103476. Epub 2013 Apr 16.

Medical Physics Department, University Hospital S. Orsola-Malpighi, Via Massarenti 9, 40138 Bologna, Italy.

In order to extract quantitative parameters from PET images, several physical effects such as photon attenuation, scatter, and partial volume must be taken into account. The main objectives of this work were the evaluation of photon attenuation in small animals and the implementation of two attenuation correction methods based on X-rays CT and segmentation of emission images. The accuracy of the first method with respect to the beam hardening effect was investigated by using Monte Carlo simulations. Mouse- and rat-sized phantoms were acquired in order to evaluate attenuation correction in terms of counts increment and recovery of uniform activity concentration. Both methods were applied to mice and rat images acquired with several radiotracers such as(18)F-FDG, (11)C-acetate, (68)Ga-chloride, and (18)F-NaF. The accuracy of the proposed methods was evaluated in heart and tumour tissues using (18)F-FDG images and in liver, kidney, and spinal column tissues using (11)C-acetate, (68)Ga-chloride, and (18)F-NaF images, respectively. In vivo results from animal studies show that, except for bone scans, differences between the proposed methods were about 10% in rats and 3% in mice. In conclusion, both methods provide equivalent results; however, the segmentation-based approach has several advantages being less time consuming and simple to implement.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2013/103476DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3652124PMC
December 2013

Feasibility of carbidopa premedication in pediatric patients: a pilot study.

Cancer Biother Radiopharm 2012 Dec 4;27(10):729-33. Epub 2012 Oct 4.

Department of Nuclear Medicine, Alma Mater Studiorum, University of Bologna, Bologna, Italy.

Aim: To verify the potential role and feasibility of carbidopa premedication in pediatric patients undergoing ¹⁸F-DOPA (Fluorine-18 fluorodihydroxyphenylalanine) PET scanning.

Materials And Methods: For this limited study, 5 patients (M:F=3:2; mean age 4.8 years) with a positive history for neuroblastoma who had been referred to our institution for instrumental monitoring during clinical follow-up were enrolled. In all cases, two consecutive ¹⁸F-DOPA PET scans, the first without carbidopa and the second with carbidopa premedication, were scheduled: patients received 4 MBq/kg of radiotracer and a dose of 2 mg/kg of carbidopa. Dedicated VOIs were drawn on the basal ganglia, pancreas, liver, and renal cortex. These regions were semiquantitatively analyzed at both the first and at the second ¹⁸F-DOPA scan, and mean SUV(max) values were compared using the t-test.

Results: On a visual basis, a clear reduction in the abdominal accumulation of (18)F-DOPA was observed in all cases after carbidopa premedication. This reduction related both to the biliary structures and the excretory system, and was accompanied by a generalized increase in soft tissue uptake. The semiquantitative analysis documented an absolute increase in SUV(max) after carbidopa premedication in the basal ganglia (3.4±1.3 vs. 2.1±0.8) and liver parenchyma (2.2±0.5 vs. 1.5±0.5), whereas SUV(max) decreased in the renal cortex (1.7±0.8 vs. 3.7±1.0) and the pancreas (2.3±0.6 vs. 3.5±0.5). The changes in SUV(max) were statistically significant for the pancreas and liver parenchyma (p=0.022 and 0.045, respectively), but not for the basal ganglia and renal cortex (p=0.143 and 0.15, respectively).

Conclusions: Carbidopa premedication in the pediatric population appears feasible and seems to influence ¹⁸F-DOPA distribution in the liver and pancreas in a manner similar to that reported in adults. Larger series are however needed to properly define the clinical role of carbidopa premedication in children.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/cbr.2012.1202.271DOI Listing
December 2012

Molecular imaging of neuroblastoma progression in TH-MYCN transgenic mice.

Mol Imaging Biol 2013 Apr;15(2):194-202

Department of Nuclear Medicine, S. Orsola-Malpighi Hospital, University of Bologna, Bologna, Italy.

Purpose: TH-MYCN transgenic mice represent a valuable preclinical model of neuroblastoma. Current methods to study tumor progression in these mice are inaccurate or invasive, limiting the potential of this murine model. The aim of our study was to assess the potential of small animal positron emission tomography (SA-PET) to study neuroblastoma progression in TH-MYCN mice.

Procedure: Serial SA-PET scans using the tracer 2-deoxy-2-[(18)F]fluoro-D-glucose ((18)F-FDG) have been performed in TH-MYCN mice. Image analysis of tumor progression has been compared with ex vivo evaluation of tumor volumes and histological features.

Results: [(18)F]FDG-SA-PET allowed to detect early staged tumors in almost 100 % of TH-MYCN mice positive for disease. Image analysis of tumor evolution reflected the modifications of the tumor volume, histological features, and malignancy during disease progression. Image analysis of TH-MYCN mice undergoing chemotherapy treatment against neuroblastoma provided information on drug-induced alterations in tumor metabolic activity.

Conclusions: These data show for the first time that [(18)F]FDG-SA-PET is a useful tool to study neuroblastoma presence and progression in TH-MYCN transgenic mice.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11307-012-0576-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3594000PMC
April 2013

Assessment of internal contamination hazard and fast monitoring for workers involved in maintenance operations on PET cyclotrons.

Radiat Prot Dosimetry 2011 Mar 3;144(1-4):468-72. Epub 2010 Nov 3.

Department of Energy, Nuclear and Environmental Control Engineering, University of Bologna, Bologna, Italy.

With the ever-increasing number of cyclotron installations, and therefore of the maintenance personnel involved, the possibility of swift, 'yes or no' screening for internal contamination becomes a prized asset. The present work presents one such procedure, evolved from an approximate whole body counting technique in widespread use in emergency situations. A detailed analysis of possible pathways for contamination leads to pinpointing the nuclides of interest. Different calibration methods are applied, showing moderate variation among them. The minimum detectable activity of order 1000 Bq is determined. The method proves sensitive enough to exclude significant contamination, or to identify its presence instantly  'on site' to prompt further in-depth investigation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/rpd/ncq327DOI Listing
March 2011

In vivo ¹⁸F-FDG tumour uptake measurements in small animals using Cerenkov radiation.

Eur J Nucl Med Mol Imaging 2011 Jan 30;38(1):120-7. Epub 2010 Sep 30.

Department of Morphological-Biomedical Sciences, Section of Anatomy and Histology, University of Verona, Strada Le Grazie N. 8, Verona, Italy.

Purpose: 2-[(18)F]Fluoro-2-deoxy-D-glucose ((18)F-FDG) is a widely used PET radiotracer for the in vivo diagnosis of several diseases such as tumours. The positrons emitted by (18)F-FDG, travelling into tissues faster than the speed of light in the same medium, are responsible for Cerenkov radiation (CR) emission which is prevalently in the visible range. The purpose of this study is to show that CR escaping from tumour tissues of small living animals injected with (18)F-FDG can be detected with optical imaging (OI) techniques using a commercial optical instrument equipped with charge-coupled detectors (CCD).

Methods: The theory behind the Cerenkov light emission and the source depth measurements using CR is first presented. Mice injected with (18)F-FDG or saline solution underwent dynamic OI acquisition and a comparison between images was performed. Multispectral analysis of the radiation was used to estimate the depth of the source of Cerenkov light. Small animal PET images were also acquired in order to compare the (18)F-FDG bio-distribution measured using OI and PET scanner.

Results: Cerenkov in vivo whole-body images of tumour-bearing mice and the measurements of the emission spectrum (560-660 nm range) are presented. Brain, kidneys and tumour were identified as a source of visible light in the animal body: the tissue time-activity curves reflected the physiological accumulation of (18)F-FDG in these organs. The identification is confirmed by the comparison between CR and (18)F-FDG images.

Conclusion: These results will allow the use of conventional OI devices for the in vivo study of glucose metabolism in cancer and the assessment, for example, of anti-cancer drugs. Moreover, this demonstrates that (18)F-FDG can be employed as it is a bimodal tracer for PET and OI techniques.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00259-010-1630-yDOI Listing
January 2011

Cerenkov radiation allows in vivo optical imaging of positron emitting radiotracers.

Phys Med Biol 2010 Jan 21;55(2):483-95. Epub 2009 Dec 21.

Medical Physics Department, San Raffaele Scientific Institute, Via Olgettina N. 60, Milan, Italy.

In this paper, we showed that Cerenkov radiation (CR) escaping from the surface of small living animals injected with (18)F-FDG can be detected with optical imaging techniques. (18)F decays by emitting positrons with a maximum energy of 0.635 MeV; such positrons, when travelling into tissues faster than the speed of light in the same medium, are responsible of CR emission. A detailed model of the CR spectrum considering the positron energy spectrum was developed in order to quantify the amount of light emission. The results presented in this work were obtained using a commercial optical imager equipped with charged coupled detectors (CCD). Our data open the door to optical imaging (OI) in vivo of the glucose metabolism, at least in pre-clinical research. We found that the heart and bladder can be clearly identified in the animal body reflecting the accumulation of the (18)F-FDG. Moreover, we describe two different methods based on the spectral analysis of the CR that can be used to estimate the depth of the source inside the animal. We conclude that (18)F-FDG can be employed as it is as a bimodal tracer for positron emission tomography (PET) and OI techniques. Our results are encouraging, suggesting that it could be possible to apply the proposed approach not only to beta(+) but also to pure beta(-) emitters.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/0031-9155/55/2/010DOI Listing
January 2010

Combined optical and single photon emission imaging: preliminary results.

Phys Med Biol 2009 Dec 17;54(23):L57-62. Epub 2009 Nov 17.

In vivo optical imaging instruments are generally devoted to the acquisition of light coming from fluorescence or bioluminescence processes. Recently, an instrument was conceived with radioisotopic detection capabilities (Kodak in Vivo Multispectral System F) based on the conversion of x-rays from the phosphorus screen. The goal of this work is to demonstrate that an optical imager (IVIS 200, Xenogen Corp., Alameda, USA), designed for in vivo acquisitions of small animals in bioluminescent and fluorescent modalities, can even be employed to detect signals due to radioactive tracers. Our system is based on scintillator crystals for the conversion of high-energy rays and a collimator. No hardware modifications are required. Crystals alone permit the acquisition of photons coming from an in vivo 20 g nude mouse injected with a solution of methyl diphosphonate technetium 99 metastable (Tc99m-MDP). With scintillator crystals and collimators, a set of measurements aimed to fully characterize the system resolution was carried out. More precisely, system point spread function and modulation transfer function were measured at different source depths. Results show that system resolution is always better than 1.3 mm when the source depth is less than 10 mm. The resolution of the images obtained with radioactive tracers is comparable with the resolution achievable with dedicated techniques. Moreover, it is possible to detect both optical and nuclear tracers or bi-modal tracers with only one instrument.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1088/0031-9155/54/23/L01DOI Listing
December 2009

Development of a modular system for the synthesis of PET [(11)C]labelled radiopharmaceuticals.

Appl Radiat Isot 2009 Oct 27;67(10):1869-73. Epub 2009 May 27.

PET Radiopharmacy, Nuclear Medicine, Azienda Ospedaliero Universitaria di Bologna, Policlinico S.Orsola-Malpighi, Bologna, Italy.

[((11))C]labelled radiopharmaceuticals as N-[(11)C]methyl-choline ([(11)C]choline), l-(S-methyl-[(11)C])methionine ([(11)C]methionine) and [(11)C]acetate have gained increasing importance in clinical PET and for the routine production of these radiopharmaceuticals, simple and reliable modules are needed to produce clinically relevant radioactivity. On the other hand, flexible devices are needed not only for the routine synthesis but also for more complex applications as the development of new tracers. The aim of this work was the adaptation of an Eckert Ziegler modular system for easy routine synthesis of [(11)C]choline, [(11)C]methionine and [(11)C]acetate using components that account for straightforward scaling up and upgrades.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.apradiso.2009.05.010DOI Listing
October 2009

Synthesis and quality control of 68Ga citrate for routine clinical PET.

Nucl Med Commun 2009 Jul;30(7):542-5

Department of Nuclear Medicine, PET Radiopharmacy, Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy.

Introduction And Aim: Scintigraphic imaging of infection and inflammation with 67Ga-citrate is an established and powerful diagnostic tool in the management of patients with infectious or inflammatory diseases. 68Ga is a short-lived positron-emitting radionuclide (half-life 67.6 min, positron energy 2.92 MeV), which allows better imaging qualities than 67Ga using the high spatial resolution and the quantitative features of PET. The aim of this study was to develop a method of synthesis for 68Ga citrate with high and reproducible radiochemical yield using a commercial 68Ga-labelling module. The resultant 68Ga citrate would be suitable for use in the detection of infectious or inflammatory diseases in routine clinical practice.

Methods: A simplified method of producing 68Ga citrate is described. Radiochemical purity, pyrogen testing were performed as per the standard protocols.

Results: After performing 10 syntheses of 68Ga citrate, the radiochemical yield was 64.1+/-6.0% (mean+/-standard deviation) with an average activity of 971.2+/-103.4 MBq available for labelling. Radiochemical purity determined by instant thin-layer chromatography-silica gel was higher than 98%. All the synthesized products were found to be sterile and pyrogen-free. In this study, the quality control step provided good and reproducible results. This is worth noting, especially in view of the stringent new rules adopted in most European countries for the in-house good manufacturing practice (GMP) synthesis of radiopharmaceuticals.

Conclusion: The high radiochemical yield and purity showed that this method is a reliable tool for the production of 68Ga citrate to be used in the detection of inflammatory and infectious diseases using high resolution and qualitative PET.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MNM.0b013e32832b9ac8DOI Listing
July 2009

Radiation emission dose from patients administered 90Y-labelled radiopharmaceuticals: comparison of experimental measurements versus Monte Carlo simulation.

Nucl Med Commun 2008 Dec;29(12):1100-5

Laboratory of Ionizing Radiation-ISPESL, Monte Porzio Catone, Roma, Italy.

Aim: To estimate the radiation dose delivered from patients injected with yttrium-90 (Y)-labelled tiuxetan (Zevalin) to parents and the general population, comparing different techniques.

Methods: The radiation dose delivered from a group of eight patients injected with Y-Zevalin to treat recurrent lymphoma was measured. The data obtained with the Monte Carlo simulation test were compared with the experimental measurements obtained with an ionization chamber detector and with a crystal NaI(Tl) detector.

Results: A good correlation was found between the Monte Carlo simulation test and the ionization chamber detector results: the air kerma dose rate was 4.2+/-0.1 and 4.4+/-0.8 microGy/h, respectively (r=0.9, P<0.01). Moreover, more than 99.7% of the air kerma dose rate measured with the ionization chamber detector was because of the contribution of electrons, whereas the contribution of photons was less than 0.3%. In contrast, the air kerma dose rate measured with the crystal NaI(Tl) detector was significantly lower (0.76+0.12 microGy/h) in comparison with the Monte Carlo simulation test. This underestimation was related to the limited crystal NaI(Tl) detector response to low energy rates at variance with the ionization chamber detector. The effective radiation dose released by patients treated with Y-labelled tiuxetan to parents and the general population was approximately 0.1 mSv per treatment cycle.

Conclusion: Using the Monte Carlo model as a benchmark to compare the experimental measurements obtained by the two different detectors, we found that the ionizing chamber detector was more accurate than the crystal Na(Tl) detector for measuring the exposure radiation dose delivered from patients administered with Y-labelled radiopharmaceuticals. Moreover, the effective radiation dose released by these patients to their parents and the general population is significantly lower than the value recommended by international reports and regulations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MNM.0b013e328314b895DOI Listing
December 2008

Reliability and reproducibility of N-[11C]methyl-choline and L-(S-methyl-[11C])methionine solid-phase synthesis: a useful and suitable method in clinical practice.

Nucl Med Commun 2008 Aug;29(8):736-40

Nuclear Medicine Unit, Medical Physics Department, S. Orsola-Malpighi Hospital, Bologna, Italy.

Background And Objective: N-[11C]methyl-choline ([11C]choline) and L-(S-methyl-[11C])methionine ([11C]methionine) are PET radiopharmaceuticals which have gained interest as oncological tracers. The increasing demand of these radiopharmaceuticals needs robust methods of synthesis with high and reproducible yield which provide enough activity for multiple patient administration in a short synthesis time.

Methods: Different synthetic approaches have been described in the literature but exhaustive reports on performance and reliability of different methods have not been described yet.

Results And Conclusion: In the present study, we demonstrated the reliability and reproducibility of the solid-phase [11C]methylation method for the synthesis of [11C]choline and [11C]methionine as a suitable tool for the routine clinical use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MNM.0b013e3282ffb44cDOI Listing
August 2008

Assessment of radionuclidic impurities in 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) routine production.

Appl Radiat Isot 2008 Mar 4;66(3):295-302. Epub 2007 Sep 4.

Medical Physics Department, S. Orsola-Malpighi Hospital, Bologna, Italy.

In this paper, radionuclidic impurities generated during the bombardment of [18 O]water in the routine production of 2-[18F]fluoro-2-deoxy-d-glucose ([18F]FDG) were studied. In order to assess such impurities and the efficacy of purification methods through the different steps of the synthesis, samples of the target filters, purification columns, [18 O]water recovered after the synthesis, and the final solution was collected and their activities measured and analyzed by means of a gamma-ray spectrometry system. The data demonstrated that purification methods adopted for the synthesis provide the [18F]FDG radionuclidically pure, as requested by the EU Pharmacopeia.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.apradiso.2007.08.015DOI Listing
March 2008

A simple Tracerlab module modification for automated on-column [11C]methylation and [11C]carboxylation.

Appl Radiat Isot 2007 Jun 8;65(6):691-5. Epub 2006 Dec 8.

Nuclear Medicine Unit, S. Orsola Hospital, Bologna, Italy.

A modification of commercial [11C]methylation module which can be implemented for both on-column [11C]methylation and [11C]carboxylation in the same automated system is described. This module configuration was applied to the solid-phase synthesis of N-[11C]methyl-choline ([11C]choline) and L-(S-methyl-[11C])methionine ([11C]methionine), using [11C]CH(3)I as methylating agent, as well as to the synthesis of [11C]acetate by [11C]carboxylation with [11C]CO2 of methylmagnesium chloride with high and reproducible radiochemical yields in short reaction time, demonstrating to be a fast and reliable tool for the production of these [11C]radiopharmaceuticals for clinical use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.apradiso.2006.10.011DOI Listing
June 2007

Detection and localization of prostate cancer: correlation of (11)C-choline PET/CT with histopathologic step-section analysis.

J Nucl Med 2005 Oct;46(10):1642-9

Nuclear Medicine Department, PET Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy.

Unlabelled: This study evaluated the potential usefulness of (11)C-choline PET/CT for detection and localization of tumors within the prostate. We used the results of step-section histopathologic examination as the standard of reference.

Methods: The results were analyzed on a sextant basis. We reviewed the results of the (11)C-choline PET/CT scans of 36 patients with prostate cancer and of 5 control subjects with bladder cancer. All patients underwent (11)C-choline PET/CT and, subsequently, radical prostatectomy with lymph node dissection within 1 mo. (11)C-Choline PET/CT scans were obtained 5-10 min after intravenous injection of 370-555 MBq of (11)C-choline. Images were reviewed visually and semiquantitatively using maximum SUV and tumor-to-background ratio.

Results: On a sextant basis, histopathologic analysis detected cancer foci in 143 of 216 sextants; high-grade prostate intraepithelial neoplasm foci were detected in 89 of 216 sextants (in 59 sextants in association with carcinoma, in 30 sextants alone), acute prostatitis was detected in 7 of 216 sextants (in 3 sextants in association with carcinoma, in 4 sextants alone), and 39 of 216 sextants were normal. PET/CT demonstrated focal (11)C-choline uptake in 108 sextants (94 of which involved tumor), and 108 sextants showed no abnormal (11)C-choline uptake (49 of which were false negative). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of PET/CT were 66%, 81%, 71%, 87%, and 55%, respectively. In the 5 control subjects, high-grade prostate intraepithelial neoplasm was detected at histologic examination in 16 of 30 sextants. PET/CT showed increased (11)C-choline uptake in 5 of 16 sextants.

Conclusion: This study demonstrated the feasibility of using (11)C-choline PET/CT to identify cancer foci within the prostate. However, we also found that (11)C-choline PET/CT has a relative high rate of false-negative results on a sextant basis and that prostatic disorders other than cancer may accumulate (11)C-choline. Therefore, our data do not support the routine use of PET/CT with (11)C-choline as a first-line screening procedure for prostate cancer in men at high risk.
View Article and Find Full Text PDF

Download full-text PDF

Source
October 2005

Potential pitfalls of 18F-FDG PET in a large series of patients treated for malignant lymphoma: prevalence and scan interpretation.

Nucl Med Commun 2005 Aug;26(8):689-94

Nuclear Medicine Department, S. Orsola-Malpighi Hospital, Bologna, Italy.

Objective: To evaluate the prevalence and scan interpretation criteria useful in identifying non-tumoural F-FDG focal uptakes (potential pitfalls) in patients who had been previously treated for a malignant lymphoma studied by positron emission tomography (PET).

Materials: Nine hundred and ninety-six consecutive PET scans obtained in 706 patients with malignant lymphoma were reviewed. All patients had been previously treated by first-line chemo-radiotherapy, plus surgery when required, and were then studied by FDG PET to investigate suspected recurrence at doubtful or inconclusive conventional radiological imaging (ultrasound, computed tomography, magnetic resonance imaging). PET was obtained with patients in the fasted condition and after i.v. injection of 370 MBq of F-FDG; imaging was acquired 60-90 min later. In patients with focal FDG uptake the final diagnosis was reached on the basis of histological findings or long-term follow-up.

Results: Thirty-one of 134 PET scans (23.1%) showing focal FDG uptake were diagnosed as non-tumoural radiotracer uptake, related to the presence of brown fat in seven cases, thymic hyperplasia in five, muscles contraction in four, lymph node unspecific inflammation in four, mediastinal/pulmonary unspecific inflammation in four, gastritis in two, colitis in two, bacterial abscess in one, lactating breast in one, and herpes zoster in one. Each of the above cited situations has been reported in the literature, generally in the form of sporadic reports, as a potential cause of misinterpretation (false positive) in reading a PET scan with the potential for incorrect patient management. An accurate diagnosis in these patients was important for the following therapeutic decision making.

Conclusions: In the whole series of patients with treated malignant lymphoma, the prevalence of non-tumoural FDG focal uptake during follow-up was relatively low (3.1%); conversely, it was relatively high when considering the sub-group of 'positive' PET only (23.1%). The importance of knowing these situations in order to avoid misinterpretation in reading PET scans needs to be emphasized. In this light, an accurate patient's history and a skilful nuclear medicine physician are very important factors. For the same purpose, it is reasonable to think that the use of hybrid PET/CT tomographs could also play an important role in helping to identify non-tumoural FDG focal uptake.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/01.mnm.0000171781.11027.bbDOI Listing
August 2005

18F-FDG PET early after radiotherapy in lymphoma patients.

Cancer Biother Radiopharm 2004 Oct;19(5):606-12

U.O. Medicina Nucleare, PET Unit, Policlinico S. Orsola-Malpighi, Bologna, Italy.

Objective: The aim of this study was to evaluate the rate of postactinic inflammatory alterations that could lead to false-positive results in FDG-PET images, in a group of lymphoma patients studied with positron emission tomography (PET) early after the end of radiation therapy.

Materials And Methods: Sixteen (16) consecutive patients were referred to our center for malignant lymphoma; 14 of 16 patients had a mediastinal bulky mass at diagnosis. Each patient underwent chemotherapy and then radiotherapy (RT): for clinical reasons, shortly after RT (range, 25-56 days; mean, 38.7 days) a FDG PET scan was required to evaluate the effect of therapy. We intravenously injected 370 MBq of 18F-FDG, and after 60-90 minutes we recorded images.

Results: Despite a relatively short time after RT, there was no pathological tracer uptake in 13 of 16 patients. In 3 cases, a mild increase in FDG uptake was observed, but no findings which would lead to a false-positive diagnosis. In 2 of 3 cases, postactinic pneumopathy was diagnosed (PET scan performed 51 and 52 days after RT); while in 1 patient, soft-tissue inflammation was present (PET scan performed 42 days after RT).

Conclusion: Our data indicates that the rate of postactinic PET inflammatory alterations in lymphoma patients is not very high and appear to be not strictly linked to the elapsed time since the end of RT treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1089/cbr.2004.19.606DOI Listing
October 2004