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Silvestre Patallo I, Subiel A, Carter R, Flynn S, Schettino G, Nisbet A. Characterization of Inorganic Scintillator Detectors for Dosimetry in Image-Guided Small Animal Radiotherapy Platforms. Cancers (Basel) 2023; 15:987. [PMID: 36765943 PMCID: PMC9913621 DOI: 10.3390/cancers15030987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/24/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
The purpose of the study was to characterize a detection system based on inorganic scintillators and determine its suitability for dosimetry in preclinical radiation research. Dose rate, linearity, and repeatability of the response (among others) were assessed for medium-energy X-ray beam qualities. The response's variation with temperature and beam angle incidence was also evaluated. Absorbed dose quality-dependent calibration coefficients, based on a cross-calibration against air kerma secondary standard ionization chambers, were determined. Relative output factors (ROF) for small, collimated fields (≤10 mm × 10 mm) were measured and compared with Gafchromic film and to a CMOS imaging sensor. Independently of the beam quality, the scintillator signal repeatability was adequate and linear with dose. Compared with EBT3 films and CMOS, ROF was within 5% (except for smaller circular fields). We demonstrated that when the detector is cross-calibrated in the user's beam, it is a useful tool for dosimetry in medium-energy X-rays with small fields delivered by Image-Guided Small Animal Radiotherapy Platforms. It supports the development of procedures for independent "live" dose verification of complex preclinical radiotherapy plans with the possibility to insert the detectors in phantoms.
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Affiliation(s)
- Ileana Silvestre Patallo
- Medical Radiation Physics and Science Groups, National Physical Laboratory (NPL), Guilford TW11 0LW, UK
| | - Anna Subiel
- Medical Radiation Physics and Science Groups, National Physical Laboratory (NPL), Guilford TW11 0LW, UK
| | - Rebecca Carter
- Cancer Institute, University College London, London WC1E 6DD, UK
| | - Samuel Flynn
- Medical Radiation Physics and Science Groups, National Physical Laboratory (NPL), Guilford TW11 0LW, UK
- School of Physics and Astronomy, University of Birmingham, Edgbaston Campus, Birmingham B15 2TT, UK
| | - Giuseppe Schettino
- Medical Radiation Physics and Science Groups, National Physical Laboratory (NPL), Guilford TW11 0LW, UK
- Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
| | - Andrew Nisbet
- Department of Medical Physics & Biomedical Engineering, University College London, Mallet Place Engineering Building, London WC1E 6BT, UK
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Wang LM, Yadav R, Serban M, Arias O, Seuntjens J, Ybarra N. Validation of an orthotopic non-small cell lung cancer mouse model, with left or right tumor growths, to use in conformal radiotherapy studies. PLoS One 2023; 18:e0284282. [PMID: 37053154 PMCID: PMC10101527 DOI: 10.1371/journal.pone.0284282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 03/27/2023] [Indexed: 04/14/2023] Open
Abstract
Orthotopic non-small cell lung cancer (NSCLC) mice models are important for establishing translatability of in vitro results. However, most orthotopic lung models do not produce localized tumors treatable by conformal radiotherapy (RT). Here we report on the performance of an orthotopic mice model featuring conformal RT treatable tumors following either left or right lung tumor cell implantation. Athymic Nude mice were surgically implanted with H1299 NSCLC cell line in either the left or right lung. Tumor development was tracked bi-weekly using computed tomography (CT) imaging. When lesions reached an appropriate size for treatment, animals were separated into non-treatment (control group) and RT treated groups. Both RT treated left and right lung tumors which were given a single dose of 20 Gy of 225 kV X-rays. Left lung tumors were treated with a two-field parallel opposed plan while right lung tumors were treated with a more conformal four-field plan to assess tumor control. Mice were monitored for 30 days after RT or after tumor reached treatment size for non-treatment animals. Treatment images from the left and right lung tumor were also used to assess the dose distribution for four distinct treatment plans: 1) Two sets of perpendicularly staggered parallel opposed fields, 2) two fields positioned in the anterior-posterior and posterior-anterior configuration, 3) an 180° arc field from 0° to 180° and 4) two parallel opposed fields which cross through the contralateral lung. Tumor volumes and changes throughout the follow-up period were tracked by three different types of quantitative tumor size approximation and tumor volumes derived from contours. Ultimately, our model generated delineable and conformal RT treatable tumor following both left and right lung implantation. Similarly consistent tumor development was noted between left and right models. We were also able to demonstrate that a single 20 Gy dose of 225 kV X-rays applied to either the right or left lung tumor models had similar levels of tumor control resulting in similar adverse outcomes and survival. And finally, three-dimensional tumor approximation featuring volume computed from the measured length across three perpendicular axes gave the best approximation of tumor volume, most closely resembled tumor volumes obtained with contours.
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Affiliation(s)
- Li Ming Wang
- Department of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- Cancer Research Program, Research Institute of the McGill University Healthcare Centre, Montreal, Quebec, Canada
| | - Ranjan Yadav
- Medical Physics Unit, Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - Monica Serban
- Radiation Medicine, Princess Margaret Cancer Centre and Department of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Department of Oncology, McGill University, Montreal, Quebec, Canada
| | - Osvaldo Arias
- Cancer Research Program, Research Institute of the McGill University Healthcare Centre, Montreal, Quebec, Canada
| | - Jan Seuntjens
- Radiation Medicine, Princess Margaret Cancer Centre and Department of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
- Department of Oncology, McGill University, Montreal, Quebec, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Norma Ybarra
- Department of Experimental Medicine, Faculty of Medicine, McGill University, Montreal, Quebec, Canada
- Cancer Research Program, Research Institute of the McGill University Healthcare Centre, Montreal, Quebec, Canada
- Department of Oncology, McGill University, Montreal, Quebec, Canada
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Kampfer S, Duda MA, Dobiasch S, Combs SE, Wilkens JJ. A comprehensive and efficient quality assurance program for an image-guided small animal irradiation system. Z Med Phys 2022; 32:261-272. [PMID: 35370028 PMCID: PMC9948878 DOI: 10.1016/j.zemedi.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 01/19/2022] [Accepted: 02/09/2022] [Indexed: 11/26/2022]
Abstract
In the field of preclinical radiotherapy, many new developments were driven by technical innovations. To make research of different groups comparable in that context and reliable, high quality has to be maintained. Therefore, standardized protocols and programs should be used. Here we present a guideline for a comprehensive and efficient quality assurance program for an image-guided small animal irradiation system, which is meant to test all the involved subsystems (imaging, treatment planning, and the irradiation system in terms of geometric accuracy and dosimetric aspects) as well as the complete procedure (end-to-end test) in a time efficient way. The suggestions are developed on a Small Animal Radiation Research Platform (SARRP) from Xstrahl (Xstrahl Ltd., Camberley, UK) and are presented together with proposed frequencies (from monthly to yearly) and experiences on the duration of each test. All output and energy related measurements showed stable results within small variation. Also, the motorized parts (couch, gantry) and other geometrical alignments were very stable. For the checks of the imaging system, the results are highly dependent on the chosen protocol and differ according to the settings. We received nevertheless stable and comparably good results for our mainly used protocol. All investigated aspects of treatment planning were exactly fulfilled and also the end-to-end test showed satisfying values. The mean overall time we needed for our checks to have a well monitored machine is less than two hours per month.
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Affiliation(s)
- Severin Kampfer
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Ismaninger Str. 22, Munich, Germany; Physics Department, Technical University of Munich (TUM), James-Franck-Str. 1, 85748, Garching, Germany.
| | - Manuela A. Duda
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Ismaninger Str. 22, Munich, Germany,Physics Department, Technical University of Munich (TUM), James-Franck-Str. 1, 85748, Garching, Germany
| | - Sophie Dobiasch
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Ismaninger Str. 22, Munich, Germany; Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany.
| | - Stephanie E. Combs
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Ismaninger Str. 22, Munich, Germany,Institute of Radiation Medicine (IRM), Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764, Neuherberg, Germany,German Cancer Consortium (DKTK), Munich, Germany
| | - Jan J. Wilkens
- Department of Radiation Oncology, School of Medicine and Klinikum rechts der Isar, Technical University of Munich (TUM), Ismaninger Str. 22, Munich, Germany,Physics Department, Technical University of Munich (TUM), James-Franck-Str. 1, 85748, Garching, Germany
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4
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Ba Sunbul N, Oraiqat I, Rosen B, Miller C, Meert C, Matuszak MM, Clarke S, Pozzi S, Moran JM, El Naqa I. Application of radiochromic gel dosimetry to commissioning of a megavoltage research linear accelerator for small-field animal irradiation studies. Med Phys 2021; 48:1404-1416. [PMID: 33378092 DOI: 10.1002/mp.14685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 11/25/2020] [Accepted: 12/17/2020] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To develop and implement an efficient and accurate commissioning procedure for small-field static beam animal irradiation studies on an MV research linear accelerator (Linatron-M9) using radiochromic gel dosimetry. MATERIALS The research linear accelerator (Linatron-M9) is a 9 MV linac with a static fixed collimator opening of 5.08 cm diameter. Lead collimators were manually placed to create smaller fields of 2 × 2 cm2 , 1 × 1 cm2 , and 0.5 × 0.5 cm2 . Relative dosimetry measurements were performed, including profiles, percent depth dose (PDD) curves, beam divergence, and relative output factors using various dosimetry tools, including a small volume ionization chamber (A14), GAFCHROMIC™ EBT3 film, and Clearview gel dosimeters. The gel dosimeter was used to provide a 3D volumetric reference of the irradiated fields. The Linatron profiles and relative output factors were extracted at a reference depth of 2 cm with the output factor measured relative to the 2 × 2 cm2 reference field. Absolute dosimetry was performed using A14 ionization chamber measurements, which were verified using a national standards laboratory remote dosimetry service. RESULTS Absolute dosimetry measurements were confirmed within 1.4% (k = 2, 95% confidence = 5%). The relative output factor of the small fields measured with films and gels agreed with a maximum relative percent error difference between the two methods of 1.1 % for the 1 × 1 cm2 field and 4.3 % for the 0.5 × 0.5 cm2 field. These relative errors were primarily due to the variability in the collimator positioning. The measured beam profiles demonstrated excellent agreement for beam size (measured as FWHM), within approximately 0.8 mm (or less). Film measurements were more accurate in the penumbra region due to the film's finer resolution compared with the gel dosimeter. Following the van Dyk criteria, the PDD values of the film and gel measurements agree within 11% in the buildup region starting from 0.5 cm depth and within 2.6 % beyond maximum dose and into the fall-off region for depths up to 5 cm. The 2D beam profile isodose lines agree within 0.5 mm in all regions for the 0.5 × 0.5 cm2 and the 1 × 1 cm2 fields and within 1 mm for the larger field of 2 × 2 cm2 . The 2D PDD curves agree within approximately 2% of the maximum in the typical therapy region (1-4 cm) for the 1 × 1 cm2 and 2 × 2 cm2 and within 5% for the 0.5 × 0.5 cm2 field. CONCLUSION This work provides a commissioning process to measure the beam characteristics of a fixed beam MV accelerator with detailed dosimetric evaluation for its implementation in megavoltage small animal irradiation studies. Radiochromic gel dosimeters are efficient small-field relative dosimetry tools providing 3D dose measurements allowing for full representation of dose, dosimeter misalignment corrections and high reproducibility with low inter-dosimeter variability. Overall, radiochromic gels are valuable for fast, full relative dosimetry commissioning in comparison to films for application in high-energy small-field animal irradiation studies.
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Affiliation(s)
- Noora Ba Sunbul
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA.,Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Ibrahim Oraiqat
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.,H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Benjamin Rosen
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Cameron Miller
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Christopher Meert
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Martha M Matuszak
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA.,Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Shaun Clarke
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Sara Pozzi
- Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, MI, USA
| | - Jean M Moran
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA
| | - Issam El Naqa
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA.,H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
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Redler G, Pearson E, Liu X, Gertsenshteyn I, Epel B, Pelizzari C, Aydogan B, Weichselbaum R, Halpern HJ, Wiersma RD. Small Animal IMRT Using 3D-Printed Compensators. Int J Radiat Oncol Biol Phys 2020; 110:551-565. [PMID: 33373659 DOI: 10.1016/j.ijrobp.2020.12.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 11/17/2020] [Accepted: 12/13/2020] [Indexed: 12/18/2022]
Abstract
PURPOSE Preclinical radiation replicating clinical intensity modulated radiation therapy (IMRT) techniques can provide data translatable to clinical practice. For this work, treatment plans were created for oxygen-guided dose-painting in small animals using inverse-planned IMRT. Spatially varying beam intensities were achieved using 3-dimensional (3D)-printed compensators. METHODS AND MATERIALS Optimized beam fluence from arbitrary gantry angles was determined using a verified model of the XRAD225Cx treatment beam. Compensators were 3D-printed with varied thickness to provide desired attenuation using copper/polylactic-acid. Spatial resolution capabilities were investigated using printed test-patterns. Following American Association of Physicists in Medicine TG119, a 5-beam IMRT plan was created for a miniaturized (∼1/8th scale) C-shape target. Electron paramagnetic resonance imaging of murine tumor oxygenation guided simultaneous integrated boost (SIB) plans conformally treating tumor to a base dose (Rx1) with boost (Rx2) based on tumor oxygenation. The 3D-printed compensator intensity modulation accuracy and precision was evaluated by individually delivering each field to a phantom containing radiochromic film and subsequent per-field gamma analysis. The methodology was validated end-to-end with composite delivery (incorporating 3D-printed tungsten/polylactic-acid beam trimmers to reduce out-of-field leakage) of the oxygen-guided SIB plan to a phantom containing film and subsequent gamma analysis. RESULTS Resolution test-patterns demonstrate practical printer resolution of ∼0.7 mm, corresponding to 1.0 mm bixels at the isocenter. The miniaturized C-shape plan provides planning target volume coverage (V95% = 95%) with organ sparing (organs at risk Dmax < 50%). The SIB plan to hypoxic tumor demonstrates the utility of this approach (hypoxic tumor V95%,Rx2 = 91.6%, normoxic tumor V95%,Rx1 = 95.7%, normal tissue V100%,Rx1 = 7.1%). The more challenging SIB plan to boost the normoxic tumor rim achieved normoxic tumor V95%,Rx2 = 90.9%, hypoxic tumor V95%,Rx1 = 62.7%, and normal tissue V100%,Rx2 = 5.3%. Average per-field gamma passing rates using 3%/1.0 mm, 3%/0.7 mm, and 3%/0.5 mm criteria were 98.8% ± 2.8%, 96.6% ± 4.1%, and 90.6% ± 5.9%, respectively. Composite delivery of the hypoxia boost plan and gamma analysis (3%/1 mm) gave passing results of 95.3% and 98.1% for the 2 measured orthogonal dose planes. CONCLUSIONS This simple and cost-effective approach using 3D-printed compensators for small-animal IMRT provides a methodology enabling preclinical studies that can be readily translated into the clinic. The presented oxygen-guided dose-painting demonstrates that this methodology will facilitate studies driving much needed biologic personalization of radiation therapy for improvements in patient outcomes.
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Affiliation(s)
- Gage Redler
- Moffitt Cancer Center, Department of Radiation Oncology, Tampa, Florida.
| | - Erik Pearson
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Xinmin Liu
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Inna Gertsenshteyn
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Boris Epel
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Charles Pelizzari
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Bulent Aydogan
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Ralph Weichselbaum
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Howard J Halpern
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, Illinois
| | - Rodney D Wiersma
- Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania
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Telarovic I, Krayenbuehl J, Grgic I, Tschanz F, Guckenberger M, Pruschy M, Unkelbach J. Probing spatiotemporal fractionation on the preclinical level. Phys Med Biol 2020; 65:22NT02. [PMID: 33179609 DOI: 10.1088/1361-6560/abbb75] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In contrast to conventional radiotherapy, spatiotemporal fractionation (STF) delivers a distinct dose distribution in each fraction. The aim is to increase the therapeutic window by simultaneously achieving partial hypofractionation in the tumour along with near uniform fractionation in normal tissues. STF has been studied in silico under the assumption that different parts of the tumour can be treated in different fractions. Here, we develop an experimental setup for testing this key assumption on the preclinical level using high-precision partial tumour irradiation in an experimental animal model. We further report on an initial proof-of-concept experiment. We consider a reductionist model of STF in which the tumour is divided in half and treated with two complementary partial irradiations separated by 24 h. Precise irradiation of both tumour halves is facilitated by the image-guided small animal radiation research platform X-RAD SmART. To assess the response of tumours to partial irradiations, tumour growth experiments are conducted using mice carrying syngeneic subcutaneous tumours derived from MC38 colorectal adenocarcinoma cells. Tumour volumes were determined daily by calliper measurements and validated by CT-volumetry. We compared the growth of conventionally treated tumours, where the whole tumour was treated in one fraction, to the reductionist model of STF. We observed no difference in growth between the two groups. Instead, a reduction in the irradiated volume (where only one half of the tumour was irradiated) resulted in an intermediate response between full irradiation and unirradiated control. The results obtained by CT-volumetry supported the findings of the calliper-derived measurements. An experimental setup for precise partial tumour irradiation in small animals was developed, which is suited to test the assumption of STF that complementary parts of the tumour can be treated in different fractions on the preclinical level. An initial experiment supports this assumption, however, further experiments with longer follow-up and varying fractionation schemes are needed to provide additional support for STF.
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Affiliation(s)
- Irma Telarovic
- Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Switzerland
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Zhong Y, Lai Y, Saha D, Story MD, Jia X, Stojadinovic S. Dose rate determination for preclinical total body irradiation. Phys Med Biol 2020; 65:175018. [PMID: 32640440 DOI: 10.1088/1361-6560/aba40f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The accuracy of delivered radiation dose and the reproducibility of employed radiotherapy methods are key factors for preclinical radiobiology applications and research studies. In this work, ionization chamber (IC) measurements and Monte Carlo (MC) simulations were used to accurately determine the dose rate for total body irradiation (TBI), a classic radiobiologic and immunologic experimental method. Several phantom configurations, including large solid water slab, small water box and rodentomorphic mouse and rat phantoms were simulated and measured for TBI setup utilizing a preclinical irradiator XRad320. The irradiator calibration and the phantom measurements were performed using an ADCL calibrated IC N31010 following the AAPM TG-61 protocol. The MC simulations were carried out using Geant4/GATE to compute absorbed dose distributions for all phantom configurations. All simulated and measured geometries had favorable agreement. On average, the relative dose rate difference was 2.3%. However, the study indicated large dose rate deviations, if calibration conditions are assumed for a given experimental setup as commonly done for a quick determination of irradiation times utilizing lookup tables and hand calculations. In a TBI setting, the reference calibration geometry at an extended source-to-surface distance and a large reference field size is likely to overestimate true photon scatter. Consequently, the measured and hand calculated dose rates, for TBI geometries in this study, had large discrepancies: 16% for a large solid water slab, 27% for a small water box, and 31%, 36%, and 30% for mouse phantom, rat phantom, and mouse phantom in a pie cage, respectively. Small changes in TBI experimental setup could result in large dose rate variations. MC simulations and the corresponding measurements specific to a designed experimental setup are vital for accurate preclinical dosimetry and reproducibility of radiobiological findings. This study supports the well-recognized need for physics consultation for all radiobiological investigations.
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Affiliation(s)
- Yuncheng Zhong
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75287, United States of America. Innovative Technologies Of Radiotherapy Computations and Hardware (iTORCH) Laboratory, Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75287, United States of America
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Spinelli AE, D'Agostino E, Broggi S, Claudio F, Boschi F. Small animal irradiator dose distribution verification using radioluminescence imaging. JOURNAL OF BIOPHOTONICS 2020; 13:e201960217. [PMID: 32163229 DOI: 10.1002/jbio.201960217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/05/2020] [Accepted: 03/08/2020] [Indexed: 06/10/2023]
Abstract
The main objective of this work was the development of a novel 2D dosimetry approach for small animal external radiotherapy using radioluminescence imaging (RLI) with a commercial complementary metal oxide semiconductor detector. Measurements of RLI were performed on the small animal image-guided platform SmART, RLI data were corrected for perspective distortion using Matlab. Four irradiation fields were tested and the planar 2D dose distributions and dose profiles were compared against dose calculations performed with a Monte Carlo based treatment planning system and gafchromic film. System linearity and RLI image noise against dose were also measured. The maximum difference between beam size measured with RLI and nominal beam size was less than 8% for all the tested beams. The image correction procedure was able to reduce perspective distortion. A novel RLI approach for quality assurance of a small animal irradiator was presented and tested. Results are in agreement with MC dose calculations and gafchromic film measurements.
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Affiliation(s)
| | | | - Sara Broggi
- Medical Physics Department, San Raffaele Scientific Institute, Italy
| | - Fiorino Claudio
- Medical Physics Department, San Raffaele Scientific Institute, Italy
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Poirier Y, Johnstone CD, Anvari A, Brodin NP, Santos MD, Bazalova-Carter M, Sawant A. A failure modes and effects analysis quality management framework for image-guided small animal irradiators: A change in paradigm for radiation biology. Med Phys 2020; 47:2013-2022. [PMID: 31986221 DOI: 10.1002/mp.14049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/17/2019] [Accepted: 01/10/2020] [Indexed: 12/28/2022] Open
Abstract
PURPOSE Image-guided small animal irradiators (IGSAI) are increasingly being adopted in radiation biology research. These animal irradiators, designed to deliver radiation with submillimeter accuracy, exhibit complexity similar to that of clinical radiation delivery systems, including image guidance, robotic stage motion, and treatment planning systems. However, physics expertise and resources are scarcer in radiation biology, which makes implementation of conventional prescriptive QA infeasible. In this study, we apply the failure modes and effect analysis (FMEA) popularized by the AAPM task group 100 (TG-100) report to IGSAI and radiation biological research. METHODS Radiation biological research requires a change in paradigm where small errors to large populations of animals are more severe than grievous errors that only affect individuals. To this end, we created a new adverse effects severity table adapted to radiation biology research based on the original AAPM TG-100 severity table. We also produced a process tree which outlines the main components of radiation biology studies performed on an IGSAI, adapted from the original clinical IMRT process tree from TG-100. Using this process tree, we created and distributed a preliminary survey to eight expert IGSAI operators in four institutions. Operators rated proposed failure modes for occurrence, severity, and lack of detectability, and were invited to share their own experienced failure modes. Risk probability numbers (RPN) were calculated and used to identify the failure modes which most urgently require intervention. RESULTS Surveyed operators indicated a number of high (RPN >125) failure modes specific to small animal irradiators. Errors due to equipment breakdown, such as loss of anesthesia or thermal control, received relatively low RPN (12-48) while errors related to the delivery of radiation dose received relatively high RPN (72-360). Errors identified could either be improved by manufacturer intervention (e.g., electronic interlocks for filter/collimator) or physics oversight (errors related to tube calibration or treatment planning system commissioning). Operators identified a number of failure modes including collision between the collimator and the stage, misalignment between imaging and treatment isocenter, inaccurate robotic stage homing/translation, and incorrect SSD applied to hand calculations. These were all relatively highly rated (90-192), indicating a possible bias in operators towards reporting high RPN failure modes. CONCLUSIONS The first FMEA specific to radiation biology research was applied to image-guided small animal irradiators following the TG-100 methodology. A new adverse effects severity table and a process tree recognizing the need for a new paradigm were produced, which will be of great use to future investigators wishing to pursue FMEA in radiation biology research. Future work will focus on expanding scope of user surveys to users of all commercial IGSAI and collaborating with manufacturers to increase the breadth of surveyed expert operators.
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Affiliation(s)
- Yannick Poirier
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Christopher Daniel Johnstone
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Physics and Astronomy, University of Victoria, Victoria, BC, Canada
| | - Akbar Anvari
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - N Patrik Brodin
- Department of Radiation Oncology, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY, USA
| | - Morgane Dos Santos
- Service de Recherche en Radiobiologie et en Médecine régénérative, Laboratoire de Radiobiologie des expositions Accidentelles, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Fontenay-aux-Roses, France
| | | | - Amit Sawant
- Department of Radiation Oncology, University of Maryland School of Medicine, Baltimore, MD, USA
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Muñoz Arango E, Peixoto JG, de Almeida CE. Small-field dosimetry with a high-resolution 3D scanning water phantom system for the small animal radiation research platform SARRP: a geometrical and quantitative study. ACTA ACUST UNITED AC 2020; 65:015012. [DOI: 10.1088/1361-6560/ab5c47] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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11
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Le Deroff C, Pérès EA, Ledoux X, Toutain J, Frelin-Labalme AM. In vivo surface dosimetry with a scintillating fiber dosimeter in preclinical image-guided radiotherapy. Med Phys 2019; 47:234-241. [PMID: 31688950 DOI: 10.1002/mp.13903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Revised: 10/25/2019] [Accepted: 10/26/2019] [Indexed: 11/10/2022] Open
Abstract
PURPOSE New preclinical image-guided irradiators and treatment planning systems represent a huge progress in radiobiology. Nevertheless, quality control of preclinical treatments is not as advanced as in clinical radiotherapy and in vivo dosimetry is less developed. In this study, we evaluate the use of a scintillating fiber dosimeter called DosiRat to verify the agreement between the doses planned with SmART-Plan and the measured doses during small animal irradiations. METHODS In vivo dosimetry was first evaluated with DosiRat through dose measurements performed at the surface of a 3 × 9 × 3 cm3 phantom. Measured and planned doses were compared for different irradiation conditions (prescription point, anterior, and posterior beams, 5 mm and 10 mm irradiation fields). In a second phase, measured and planned doses were compared for rat brain irradiations performed with anterior beams, with DosiRat positioned at the beam entrance. Comparisons were performed for different tube currents (1.3 and 13 mA), collimations (5, 10 and 25 mm diameter), and planned doses (0.1, 0.5, 2, and 10 Gy). RESULTS In the case of the phantom irradiations, planned and measured doses showed discrepancies smaller than the 5% accuracy of the TPS, except in cases in which the dosimeter was not centered in the irradiation field. The differences were larger for animal irradiations (from -3.3% to 8.8%) because of variations of the beam energy spectrum and the nonequivalence between materials at medium and low energy. CONCLUSIONS This study highlighted the complexity to implement one-dimension in vivo dosimetry in orthovoltage millimetric beams. Nevertheless, DosiRat is well adapted to in vivo dosimetry because of its small volume and its direct reading and allowed in vivo control of planned doses for anterior beams down to 5 mm diameter.
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Affiliation(s)
- Coralie Le Deroff
- Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF, CNRS/IN2P3, Boulevard Henri Becquerel, 14076, Caen, France
| | - Elodie A Pérès
- Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Xavier Ledoux
- Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF, CNRS/IN2P3, Boulevard Henri Becquerel, 14076, Caen, France
| | - Jérôme Toutain
- Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/CERVOxy Group, Caen, France
| | - Anne-Marie Frelin-Labalme
- Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF, CNRS/IN2P3, Boulevard Henri Becquerel, 14076, Caen, France.,Advanced Resource Centre for Hadrontherapy in Europe (ARCHADE) Program, Caen, France
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12
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Biglin ER, Price GJ, Chadwick AL, Aitkenhead AH, Williams KJ, Kirkby KJ. Preclinical dosimetry: exploring the use of small animal phantoms. Radiat Oncol 2019; 14:134. [PMID: 31366364 PMCID: PMC6670203 DOI: 10.1186/s13014-019-1343-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/22/2019] [Indexed: 11/16/2022] Open
Abstract
Preclinical radiotherapy studies using small animals are an indispensable step in the pathway from in vitro experiments to clinical implementation. As radiotherapy techniques advance in the clinic, it is important that preclinical models evolve to keep in line with these developments. The use of orthotopic tumour sites, the development of tissue-equivalent mice phantoms and the recent introduction of image-guided small animal radiation research platforms has enabled similar precision treatments to be delivered in the laboratory. These technological developments, however, are hindered by a lack of corresponding dosimetry standards and poor reporting of methodologies. Without robust and well documented preclinical radiotherapy quality assurance processes, it is not possible to ensure the accuracy and repeatability of dose measurements between laboratories. As a consequence current RT-based preclinical models are at risk of becoming irrelevant. In this review we explore current standardization initiatives, focusing in particular on recent developments in small animal irradiation equipment, 3D printing technology to create customisable tissue-equivalent dosimetry phantoms and combining these phantoms with commonly used detectors.
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Affiliation(s)
- Emma R Biglin
- Division of Cancer Sciences, University of Manchester, Manchester Cancer Research Centre, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK.
| | - Gareth J Price
- Division of Cancer Sciences, University of Manchester, Manchester Cancer Research Centre, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK.,The Christie NHS Foundation Trust, Manchester, UK
| | - Amy L Chadwick
- Division of Cancer Sciences, University of Manchester, Manchester Cancer Research Centre, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK.,The Christie NHS Foundation Trust, Manchester, UK
| | - Adam H Aitkenhead
- Division of Cancer Sciences, University of Manchester, Manchester Cancer Research Centre, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK.,The Christie NHS Foundation Trust, Manchester, UK
| | - Kaye J Williams
- Division of Pharmacy and Optometry, University of Manchester, Manchester, UK
| | - Karen J Kirkby
- Division of Cancer Sciences, University of Manchester, Manchester Cancer Research Centre, 3rd floor Proton Beam Therapy Centre, Oak Road, Manchester, M20 4BX, UK.,The Christie NHS Foundation Trust, Manchester, UK
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13
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Soultanidis G, Subiel A, Renard I, Reinhart AM, Green VL, Oelfke U, Archibald SJ, Greenman J, Tulk A, Walker A, Schettino G, Cawthorne CJ. Development of an anatomically correct mouse phantom for dosimetry measurement in small animal radiotherapy research. Phys Med Biol 2019; 64:12NT02. [PMID: 31082807 DOI: 10.1088/1361-6560/ab215b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Significant improvements in radiotherapy are likely to come from biological rather than technical optimization, for example increasing tumour radiosensitivity via combination with targeted therapies. Such paradigms must first be evaluated in preclinical models for efficacy, and recent advances in small animal radiotherapy research platforms allow advanced irradiation protocols, similar to those used clinically, to be carried out in orthotopic models. Dose assessment in such systems is complex however, and a lack of established tools and methodologies for traceable and accurate dosimetry is currently limiting the capabilities of such platforms and slowing the clinical uptake of new approaches. Here we report the creation of an anatomically correct phantom, fabricated from materials with tissue-equivalent electron density, into which dosimetry detectors can be incorporated for measurement as part of quality control (QC). The phantom also allows training in preclinical radiotherapy planning and cross-institution validation of dose delivery protocols for small animal radiotherapy platforms without the need to sacrifice animals, with high reproducibility. Mouse CT data was acquired and segmented into soft tissue, bone and lung. The skeleton was fabricated using 3D printing, whilst lung was created using computer numerical control (CNC) milling. Skeleton and lung were then set into a surface-rendered mould and soft tissue material added to create a whole-body phantom. Materials for fabrication were characterized for atomic composition and attenuation for x-ray energies typically found in small animal irradiators. Finally cores were CNC milled to allow intracranial incorporation of bespoke detectors (alanine pellets) for dosimetry measurement.
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Affiliation(s)
- George Soultanidis
- Department of Biomedical Sciences, University of Hull, Hull, United Kingdom. Translational and Molecular Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
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14
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Feddersen TV, Rowshanfarzad P, Abel TN, Ebert MA. Commissioning and performance characteristics of a pre-clinical image-guided radiotherapy system. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2019; 42:541-551. [PMID: 30989595 PMCID: PMC6557883 DOI: 10.1007/s13246-019-00755-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 04/01/2019] [Indexed: 12/21/2022]
Abstract
Characteristics of a small-animal radiotherapy device, the X-RAD SmART, are described following commissioning of the device for pre-clinical radiotherapy research. Performance characteristics were assessed using published standards and compared with previous results published for similar systems. Operational radiation safety was established. Device X-ray beam quality and output dose-rate were found to be consistent with those reported for similar devices. Output steadily declined over 18 months though remained within tolerance levels. There is considerable variation in output factor across the international installations for the smallest field size (varying by more than 30% for 2.5 mm diameter fields). Measured depth dose and profile data was mostly consistent with that published, with some differences in penumbrae and generally reduced flatness. Target localisation is achieved with an imaging panel and with automatic corrections for panel flex and device mechanical instability, targeting within 0.2 mm is achievable. The small-animal image-guided radiotherapy platform has been implemented and assessed and found to perform as specified. The combination of kV energy and high spatial precision make it suitable for replicating clinical dose distributions at the small-animal scale, though dosimetric uncertainties for the narrowest fields need to be acknowledged.
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Affiliation(s)
- Theresa V Feddersen
- Department of Physics, University of Western Australia, Crawley, WA, Australia.
- Department of Radiotherapy, Erasmus University Medical Center, Rotterdam, The Netherlands.
- Department of Radiology & Nuclear Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
| | | | - Tamara N Abel
- Telethon Kids Institute, University of Western Australia, Subiaco, WA, Australia
| | - Martin A Ebert
- Department of Physics, University of Western Australia, Crawley, WA, Australia
- Department of Radiation Oncology, Sir Charles Gairdner Hospital, Nedlands, WA, Australia
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15
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Le Deroff C, Frelin AM, Ledoux X. Energy dependence of a scintillating fiber detector for preclinical dosimetry with an image guided micro-irradiator. Phys Med Biol 2019; 64:115015. [PMID: 30974415 DOI: 10.1088/1361-6560/ab1854] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The dosimetry of preclinical micro-irradiators is challenging due to their millimetric beams and medium x-ray energy range. Plastic scintillator dosimeters (PSD) are good candidates for such a purpose as they provide a high spatial resolution although they show an energy dependence below 100 keV. The purpose of this study was to assess the energy dependence of a dedicated PSD (called DosiRat) for micro-irradiators dosimetry. The response of the PSD relative to air kerma was measured for different beam qualities (40-225 kV) with the X-RAD 225Cx irradiator. The corresponding energy spectra, determined by Monte Carlo simulations, allowed for correcting the differences in absorbed dose between the DosiRat material (polystyrene) and the air and therefore allowed to compare DosiRat intrinsic energy response to the Birks scintillation quenching model. The energy response of DosiRat was then assessed under preclinical conditions through percentage depth dose curves (PDD) and relative output factor (ROF) measurements in water for beam diameters ranging from 1 to 25 mm. DosiRat energy response showed a coefficient of variation of 23% from 40 to 225 kV, mainly explained by the mass energy-absorption coefficient variation between polystyrene and air. A remaining variation was shown to be caused by the quenching of the scintillation and was correctly reproduced by the Birks model (with kB = 10.27 mg MeV-1 cm-2). PDD and ROF measurements highlighted an energy response variation with depth and collimation up to 10%. A dose accuracy better than 1% was finally achieved with appropriate calibration and correction factors (CF), for beam collimations larger than the detector ([Formula: see text]2 mm diameter). DosiRat energy dependence was fully characterized in preclinical energy range and shown to be negligible with convenient calibration and corrections factors. It provided accurate dosimetry for medium energy (225 kV) and millimetric beams (down to 2.5 mm).
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Affiliation(s)
- C Le Deroff
- Grand accélérateur National d'Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Boulevard Henri Becquerel, 14076 Caen, France. Author to whom any correspondence should be addressed
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16
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Sosa Iglesias V, van Hoof SJ, Vaniqui A, Schyns LE, Lieuwes N, Yaromina A, Spiegelberg L, Groot AJ, Verhaegen F, Theys J, Dubois L, Vooijs M. An orthotopic non-small cell lung cancer model for image-guided small animal radiotherapy platforms. Br J Radiol 2018; 92:20180476. [PMID: 30465693 DOI: 10.1259/bjr.20180476] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
METHODS: An orthotopic non-small cell lung cancer model in NMRI-nude mice was established to investigate the complementary information acquired from 80 kVp microcone-beam CT (micro-CBCT) and bioluminescence imaging (BLI) using different angles and filter settings. Different micro-CBCT-based radiation-delivery plans were evaluated based on their dose-volume histogram metrics of tumor and organs at risk to select the optimal treatment plan. RESULTS: H1299 cell suspensions injected directly into the lung render exponentially growing single tumor nodules whose CBCT-based volume quantification strongly correlated with BLI-integrated intensity. Parallel-opposed single angle beam plans through a single lung are preferred for smaller tumors, whereas for larger tumors, plans that spread the radiation dose across healthy tissues are favored. CONCLUSIONS: Closely mimicking a clinical setting for lung cancer with highly advanced preclinical radiation treatment planning is possible in mice developing orthotopic lung tumors. ADVANCES IN KNOWLEDGE: BLI and CBCT imaging of orthotopic lung tumors provide complementary information in a temporal manner. The optimal radiotherapy plan is tumor volume-dependent.
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Affiliation(s)
- Venus Sosa Iglesias
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | | | - Ana Vaniqui
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Lotte Ejr Schyns
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Natasja Lieuwes
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Ala Yaromina
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Linda Spiegelberg
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Arjan J Groot
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Frank Verhaegen
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Jan Theys
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Ludwig Dubois
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
| | - Marc Vooijs
- 1 Department of Radiotherapy, GROW-School for Oncology & Developmental Biology, Maastricht University Medical Centre , Maastricht , The Netherlands
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17
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Poirier Y, Johnstone CD, Kirkby C. The potential impact of ultrathin filter design on dosimetry and relative biological effectiveness in modern image-guided small animal irradiators. Br J Radiol 2018; 92:20180537. [PMID: 30281330 DOI: 10.1259/bjr.20180537] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE: Modern image-guided small animal irradiators like the Xstrahl Small Animal Radiation Research Platform (SARRP) are designed with ultrathin 0.15 mm Cu filters, which compared with more heavily filtrated traditional cabinet-style biological irradiators, produce X-ray spectra weighted toward lower energies, impacting the dosimetric properties and the relative biological effectiveness (RBE). This study quantifies the effect of ultrathin filter design on relative depth dose profiles, absolute dose output, and RBE using Monte Carlo techniques. METHODS: The percent depth-dose and absolute dose output are calculated using kVDoseCalc and EGSnrc, respectively, while a tally based on the induction of double-strand breaks as a function of electron spectra invoked in PENELOPE is used to estimate the RBE. RESULTS: The RBE increases by >2.4% in the ultrathin filter design compared to a traditional irradiator. Furthermore, minute variations in filter thickness have notable effects on the dosimetric properties of the X-ray beam, increasing the percent depth dose (at 2 cm in water) by + 0.4%/0.01 mm Cu and decreasing absolute dose (at 2 cm depth in water) by -1.8%/0.01 mm Cu for the SARRP. CONCLUSIONS: These results show that modern image-guided irradiators are quite sensitive to small manufacturing variations in filter thickness, and show a small change in RBE compared to traditional X-ray irradiators. ADVANCES IN KNOWLEDGE: We quantify the consequences of ultrathin filter design in modern image-guided biological irradiators on relative and absolute dose, and RBE. Our results show these to be small, but not insignificant, suggesting laboratories transitioning between irradiators should carefully design their radiobiological experiments.
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Affiliation(s)
- Yannick Poirier
- 1 Department of Radiation Oncology, Division of Translational Radiation Sciences, University of Maryland School of Medicine , Baltimore, MD , USA.,2 Department of Radiation Oncology, Division of Medical Physics, University of Maryland School of Medicine , Baltimore, MD , USA
| | - Christopher Daniel Johnstone
- 1 Department of Radiation Oncology, Division of Translational Radiation Sciences, University of Maryland School of Medicine , Baltimore, MD , USA.,3 Department of Physics and Astronomy, University of Victoria , Victoria, BC , Canada
| | - Charles Kirkby
- 4 Department of Medical Physics, Jack Ady Cancer Center , Lethbridge, AB , Canada.,5 Department of Physics and Astronomy, University of Calgary , Calgary, AB , Canada.,6 Department of Oncology, University of Calgary , Calgary, AB , Canada
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18
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Anvari A, Poirier Y, Sawant A. Development and implementation of
EPID
‐based quality assurance tests for the small animal radiation research platform (
SARRP
). Med Phys 2018; 45:3246-3257. [DOI: 10.1002/mp.12939] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/13/2018] [Accepted: 04/10/2018] [Indexed: 11/10/2022] Open
Affiliation(s)
- Akbar Anvari
- Department of Radiation Oncology University of Maryland School of Medicine Baltimore MD 21201 USA
| | - Yannick Poirier
- Department of Radiation Oncology University of Maryland School of Medicine Baltimore MD 21201 USA
| | - Amit Sawant
- Department of Radiation Oncology University of Maryland School of Medicine Baltimore MD 21201 USA
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19
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Khan M, Heilemann G, Kuess P, Georg D, Berg A. The impact of the oxygen scavenger on the dose-rate dependence and dose sensitivity of MAGIC type polymer gels. ACTA ACUST UNITED AC 2018. [DOI: 10.1088/1361-6560/aab00b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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20
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Verhaegen F, Dubois L, Gianolini S, Hill MA, Karger CP, Lauber K, Prise KM, Sarrut D, Thorwarth D, Vanhove C, Vojnovic B, Weersink R, Wilkens JJ, Georg D. ESTRO ACROP: Technology for precision small animal radiotherapy research: Optimal use and challenges. Radiother Oncol 2018; 126:471-478. [PMID: 29269093 DOI: 10.1016/j.radonc.2017.11.016] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 11/21/2017] [Indexed: 11/30/2022]
Abstract
Many radiotherapy research centers have recently installed novel research platforms enabling the investigation of the radiation response of tumors and normal tissues in small animal models, possibly in combination with other treatment modalities. Many more research institutes are expected to follow in the coming years. These novel platforms are capable of mimicking human radiotherapy more closely than older technology. To facilitate the optimal use of these novel integrated precision irradiators and various small animal imaging devices, and to maximize the impact of the associated research, the ESTRO committee on coordinating guidelines ACROP (Advisory Committee in Radiation Oncology Practice) has commissioned a report to review the state of the art of the technology used in this new field of research, and to issue recommendations. This report discusses the combination of precision irradiation systems, small animal imaging (CT, MRI, PET, SPECT, bioluminescence) systems, image registration, treatment planning, and data processing. It also provides guidelines for reporting on studies.
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Affiliation(s)
- Frank Verhaegen
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands
| | - Ludwig Dubois
- Department of Radiation Oncology (MAASTRO), GROW - School for Oncology and Developmental Biology, Maastricht University Medical Centre, The Netherlands
| | | | - Mark A Hill
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, UK
| | - Christian P Karger
- Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg, Germany; National Center for Radiation Research in Oncology (NCRO), Heidelberg Institute for Radiation Oncology (HIRO), Heidelberg, Germany
| | - Kirsten Lauber
- Department of Radiation Oncology, University Hospital, Ludwig-Maximilians-University of Munich, Germany
| | - Kevin M Prise
- Centre for Cancer Research & Cell Biology, Queen's University Belfast, UK
| | - David Sarrut
- Université de Lyon, CREATIS, CNRS UMR5220, Inserm U1044, INSA-Lyon, Université Lyon 1, Centre Léon Bérard, France
| | - Daniela Thorwarth
- Section for Biomedical Physics, Department of Radiation Oncology, University Hospital Tübingen, Germany
| | - Christian Vanhove
- Institute Biomedical Technology (IBiTech), Medical Imaging and Signal Processing (MEDISIP), Ghent University, Belgium
| | - Boris Vojnovic
- CRUK/MRC Oxford Institute for Radiation Oncology, University of Oxford, Gray Laboratories, UK
| | - Robert Weersink
- Department of Radiation Oncology, University of Toronto, Department of Radiation Medicine, Princess Margaret Hospital, Canada
| | - Jan J Wilkens
- Department of Radiation Oncology, Technical University of Munich, Klinikum rechts der Isar, Germany
| | - Dietmar Georg
- Division of Medical Radiation Physics, Department of Radiation Oncology and Christian Doppler Laboratory for Medical Radiation Research for Radiation Oncology, Medical University of Vienna, Austria
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21
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Ghita M, McMahon SJ, Thompson HF, McGarry CK, King R, Osman SOS, Kane JL, Tulk A, Schettino G, Butterworth KT, Hounsell AR, Prise KM. Small field dosimetry for the small animal radiotherapy research platform (SARRP). Radiat Oncol 2017; 12:204. [PMID: 29282134 PMCID: PMC5745702 DOI: 10.1186/s13014-017-0936-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 12/02/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Preclinical radiation biology has become increasingly sophisticated due to the implementation of advanced small animal image guided radiation platforms into laboratory investigation. These small animal radiotherapy devices enable state-of-the-art image guided therapy (IGRT) research to be performed by combining high-resolution cone beam computed tomography (CBCT) imaging with an isocentric irradiation system. Such platforms are capable of replicating modern clinical systems similar to those that integrate a linear accelerator with on-board CBCT image guidance. METHODS In this study, we present a dosimetric evaluation of the small animal radiotherapy research platform (SARRP, Xstrahl Inc.) focusing on small field dosimetry. Physical dosimetry was assessed using ion chamber for calibration and radiochromic film, investigating the impact of beam focus size on the dose rate output as well as beam characteristics (beam shape and penumbra). Two film analysis tools) have been used to assess the dose output using the 0.5 mm diameter aperture. RESULTS Good agreement (between 1.7-3%) was found between the measured physical doses and the data provided by Xstrahl for all apertures used. Furthermore, all small field dosimetry data are in good agreement for both film reading methods and with our Monte Carlo simulations for both focal spot sizes. Furthermore, the small focal spot has been shown to produce a more homogenous beam with more stable penumbra over time. CONCLUSIONS FilmQA Pro is a suitable tool for small field dosimetry, with a sufficiently small sampling area (0.1 mm) to ensure an accurate measurement. The electron beam focus should be chosen with care as this can potentially impact on beam stability and reproducibility.
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Affiliation(s)
- Mihaela Ghita
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.
| | - Stephen J McMahon
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Hannah F Thompson
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Conor K McGarry
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Raymond King
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.,Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Sarah O S Osman
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK.,Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Jonathan L Kane
- Xstrahl Inc, 480 Brogdon Road, Suite 300, Suwanee, GA, 30024, USA
| | - Amanda Tulk
- Xstrahl Ltd, The Coliseum, Watchmoor Park, Riverside Way, Camberley, Surrey, GU15 3YL, UK
| | - Giuseppe Schettino
- National Physical Laboratory, Hampton Road, Teddington, Middlesex, TW11 0LW, UK
| | - Karl T Butterworth
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
| | - Alan R Hounsell
- Radiotherapy Physics, Northern Ireland Cancer Centre, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Kevin M Prise
- Centre for Cancer Research and Cell Biology, Queen's University Belfast, 97 Lisburn Road, Belfast, BT9 7AE, UK
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22
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Prajapati S, Cox B, Swader R, Petry G, Eliceiri KW, Jeraj R, Mackie TR. Design of an Open-Source Binary Micromultileaf Collimator for a Small Animal Microradiotherapy System. J Med Device 2017. [DOI: 10.1115/1.4038017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Intensity modulated radiation therapy (IMRT) is performed on a regular basis in the clinic to create complex radiation fields to treat cancer, but it has not been implemented in microradiotherapy (mRT) for preclinical systems. A multileaf collimator (MLC) is an integral part of a radiotherapy system that allows IMRT application. Presented here is the development of a key component of an open source mRT system for preclinical research. We have designed and fabricated a binary micro multileaf collimator (bmMLC) for mRT that can provide 1 mm or better resolution at isocenter and attenuate over 98% of a 250 kVp X-ray beam. This is the smallest collimator system designed for RT systems, with 20 brass leaves, each 0.5 mm thick, creating a physical field opening of 1 cm × 1 cm. The mode of actuation for the leaves was rotational, rather than linear, which is typical in larger clinical RT systems. The design presented here met the identified design requirements and represents a rigorous design process, during which several less successful designs were investigated and eventually discarded. After the fabrication of the design, dosimetric characteristics were tested and requirements were met. The final bmMLC designs and technical documents are made available as open-source.
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Affiliation(s)
- Surendra Prajapati
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 1005, Madison, WI 53705
- Morgridge Institute for Research, 330 North Orchard Street, Madison, WI 53715 e-mail:
| | - Benjamin Cox
- Morgridge Institute for Research, 330 North Orchard Street, Madison, WI 53715
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 1005, Madison, WI 53705 e-mail:
| | - Robert Swader
- Morgridge Institute for Research, 330 North Orchard Street, Madison, WI 53715 e-mail:
| | - George Petry
- Morgridge Institute for Research, 330 North Orchard Street, Madison, WI 53715 e-mail:
| | - Kevin W. Eliceiri
- Morgridge Institute for Research, 330 North Orchard Street, Madison, WI 53715
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 1005, Madison, WI 53705 e-mail:
| | - Robert Jeraj
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 1005, Madison, WI 53705 e-mail:
| | - Thomas R. Mackie
- Department of Medical Physics, University of Wisconsin-Madison, 1111 Highland Avenue, Room 1005, Madison, WI 53705
- Morgridge Institute for Research, 330 North Orchard Street, Madison, WI 53715 e-mail:
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Zanette B, Stirrat E, Jelveh S, Hope A, Santyr G. Detection of regional radiation-induced lung injury using hyperpolarized 129Xe chemical shift imaging in a rat model involving partial lung irradiation: Proof-of-concept demonstration. Adv Radiat Oncol 2017; 2:475-484. [PMID: 29114616 PMCID: PMC5605308 DOI: 10.1016/j.adro.2017.05.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 05/19/2017] [Indexed: 12/25/2022] Open
Abstract
PURPOSE The purpose of this work was to use magnetic resonance imaging (MRI) of hyperpolarized (HP) 129Xe dissolved in pulmonary tissue (PT) and red blood cells (RBCs) to detect regional changes to PT structure and perfusion in a partial-lung rat model of radiation-induced lung injury and compare with histology. METHODS AND MATERIALS The right medial region of the lungs of 6 Sprague-Dawley rats was irradiated (20 Gy, single-fraction). A second nonirradiated cohort served as the control group. Imaging was performed 4 weeks after irradiation to quantify intensity and heterogeneity of PT and RBC 129Xe signals. Imaging findings were correlated with measures of PT and RBC distribution. RESULTS Asymmetric (right vs left) changes in 129Xe signal intensity and heterogeneity were observed in the irradiated cohort but were not seen in the control group. PT signal was observed to increase in intensity and heterogeneity and RBC signal was observed to increase in heterogeneity in the irradiated right lungs, consistent with histology. CONCLUSION Regional changes to PT and RBC 129Xe signals are detectable 4 weeks following partial-lung irradiation in rats.
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Affiliation(s)
- Brandon Zanette
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario
- Physiology & Experimental Medicine Program, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario
| | - Elaine Stirrat
- Physiology & Experimental Medicine Program, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario
| | - Salomeh Jelveh
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario
| | - Andrew Hope
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario
- Department of Radiation Oncology, University of Toronto, Toronto, Ontario
| | - Giles Santyr
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario
- Physiology & Experimental Medicine Program, Peter Gilgan Centre for Research and Learning, The Hospital for Sick Children, Toronto, Ontario
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Adamson J, Mein S, Meng B, Gunasingha R, Yoon SW, Miles D, Walder H, Fathi Z, Beyer W, Spector N, Gieger TL, Nolan MW, Oldham M. Utilizing a diagnostic kV imaging system for x-ray psoralen activated cancer therapy (X-PACT). Biomed Phys Eng Express 2017. [DOI: 10.1088/2057-1976/aa6e58] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Welch ML, Jaffray DA. The correction of time and temperature effects in MR-based 3D Fricke xylenol orange dosimetry. Phys Med Biol 2017; 62:3221-3236. [PMID: 28164865 DOI: 10.1088/1361-6560/aa5e63] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Previously developed MR-based three-dimensional (3D) Fricke-xylenol orange (FXG) dosimeters can provide end-to-end quality assurance and validation protocols for pre-clinical radiation platforms. FXG dosimeters quantify ionizing irradiation induced oxidation of Fe2+ ions using pre- and post-irradiation MR imaging methods that detect changes in spin-lattice relaxation rates (R 1 = [Formula: see text]) caused by irradiation induced oxidation of Fe2+. Chemical changes in MR-based FXG dosimeters that occur over time and with changes in temperature can decrease dosimetric accuracy if they are not properly characterized and corrected. This paper describes the characterization, development and utilization of an empirical model-based correction algorithm for time and temperature effects in the context of a pre-clinical irradiator and a 7 T pre-clinical MR imaging system. Time and temperature dependent changes of R 1 values were characterized using variable TR spin-echo imaging. R 1-time and R 1-temperature dependencies were fit using non-linear least squares fitting methods. Models were validated using leave-one-out cross-validation and resampling. Subsequently, a correction algorithm was developed that employed the previously fit empirical models to predict and reduce baseline R 1 shifts that occurred in the presence of time and temperature changes. The correction algorithm was tested on R 1-dose response curves and 3D dose distributions delivered using a small animal irradiator at 225 kVp. The correction algorithm reduced baseline R 1 shifts from -2.8 × 10-2 s-1 to 1.5 × 10-3 s-1. In terms of absolute dosimetric performance as assessed with traceable standards, the correction algorithm reduced dose discrepancies from approximately 3% to approximately 0.5% (2.90 ± 2.08% to 0.20 ± 0.07%, and 2.68 ± 1.84% to 0.46 ± 0.37% for the 10 × 10 and 8 × 12 mm2 fields, respectively). Chemical changes in MR-based FXG dosimeters produce time and temperature dependent R 1 values for the time intervals and temperature changes found in a typical small animal imaging and irradiation laboratory setting. These changes cause baseline R 1 shifts that negatively affect dosimeter accuracy. Characterization, modeling and correction of these effects improved in-field reported dose accuracy to less than 1% when compared to standardized ion chamber measurements.
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Affiliation(s)
- Mattea L Welch
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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26
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Felix MC, Glatting G, Giordano FA, Brockmann MA, Wenz F, Fleckenstein J. Collimator optimization for small animal radiation therapy at a micro-CT. Z Med Phys 2017; 27:56-64. [DOI: 10.1016/j.zemedi.2016.05.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 05/22/2016] [Accepted: 05/25/2016] [Indexed: 11/16/2022]
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Koontz BF, Verhaegen F, De Ruysscher D. Tumour and normal tissue radiobiology in mouse models: how close are mice to mini-humans? Br J Radiol 2017; 90:20160441. [PMID: 27612010 PMCID: PMC5605019 DOI: 10.1259/bjr.20160441] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 08/30/2016] [Accepted: 09/07/2016] [Indexed: 11/05/2022] Open
Abstract
Animal modelling is essential to the study of radiobiology and the advancement of clinical radiation oncology by providing preclinical data. Mouse models in particular have been highly utilized in the study of both tumour and normal tissue radiobiology because of their cost effectiveness and versatility. Technology has significantly advanced in preclinical radiation techniques to allow highly conformal image-guided irradiation of small animals in an effort to mimic human treatment capabilities. However, the biological and physical limitations of animal modelling should be recognized and considered when interpreting preclinical radiotherapy (RT) studies. Murine tumour and normal tissue radioresponse has been shown to vary from human cellular and molecular pathways. Small animal irradiation techniques utilize different anatomical boundaries and may have different physical properties than human RT. This review addresses the difference between the human condition and mouse models and discusses possible strategies for future refinement of murine models of cancer and radiation for the benefit of both basic radiobiology and clinical translation.
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Affiliation(s)
- Bridget F Koontz
- Department of Radiation Oncology, Duke Cancer Institute, Durham, NC, USA
| | - Frank Verhaegen
- Department of Radiation Oncology (MAASTRO), GROW—School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, Netherlands
| | - Dirk De Ruysscher
- Department of Radiation Oncology (MAASTRO), GROW—School for Oncology and Developmental Biology, Maastricht University Medical Centre, Maastricht, Netherlands
- Department of Oncology, Catholic University of Leuven, Leuven, Belgium
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Le Deroff C, Frelin-Labalme AM, Ledoux X. Characterization of a scintillating fibre detector for small animal imaging and irradiation dosimetry. Br J Radiol 2016; 90:20160454. [PMID: 27556813 DOI: 10.1259/bjr.20160454] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE Small animal image-guided irradiators have recently been developed to mimic the delivery techniques of clinical radiotherapy. A dosemeter adapted to millimetric beams of medium-energy X-rays is then required. This work presents the characterization of a dosemeter prototype for this particular application. METHODS A scintillating optical fibre dosemeter (called DosiRat) has been implemented to perform real-time dose measurements with the dedicated small animal X-RAD® 225Cx (Precision X-Ray, Inc., North Branford, CT) irradiator. Its sensitivity, stem effect, stability, linearity and measurement precision were determined in large field conditions for three different beam qualities, consistent with small animal irradiation and imaging parameters. RESULTS DosiRat demonstrates good sensitivity and stability; excellent air kerma and air kerma rate linearity; and a good repeatability for air kerma rates >1 mGy s-1. The stem effect was found to be negligible. DosiRat showed limited precision for low air kerma rate measurements (<1 mGy s-1), typically for imaging protocols. A positive energy dependence was found that can be accounted for by calibrating the dosemeter at the needed beam qualities. CONCLUSION The dosimetric performances of DosiRat are very promising. Extensive studies of DosiRat energy dependence are still required. Further developments will allow to reduce the dosemeter size to ensure millimetric beams dosimetry and perform small animal in vivo dosimetry. Advances in knowledge: Among existing point dosemeters, very few are dedicated to both medium-energy X-rays and millimetric beams. Our work demonstrated that scintillating fibre dosemeters are suitable and promising tools for real-time dose measurements in the small animal field of interest.
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Affiliation(s)
- Coralie Le Deroff
- 1 Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Boulevard Henri Becquerel, 14076 Caen, France
| | - Anne-Marie Frelin-Labalme
- 1 Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Boulevard Henri Becquerel, 14076 Caen, France.,2 Advanced Resource Centre for HADrontherapy in Europe (ARCHADE) Program, Caen, France
| | - Xavier Ledoux
- 1 Grand Accélérateur National d'Ions Lourds (GANIL), CEA/DRF-CNRS/IN2P3, Boulevard Henri Becquerel, 14076 Caen, France
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Moore CS, Wood TJ, Cawthorne C, Hilton KL, Maher S, Saunderson JR, Archibald S, Beavis AW. A method to calibrate the RS 2000 x-ray biological irradiator for radiobiological flank irradiation of mice. Biomed Phys Eng Express 2016. [DOI: 10.1088/2057-1976/2/3/037001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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30
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Noblet C, Chiavassa S, Smekens F, Sarrut D, Passal V, Suhard J, Lisbona A, Paris F, Delpon G. Validation of fast Monte Carlo dose calculation in small animal radiotherapy with EBT3 radiochromic films. Phys Med Biol 2016; 61:3521-35. [DOI: 10.1088/0031-9155/61/9/3521] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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31
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Tillner F, Thute P, Löck S, Dietrich A, Fursov A, Haase R, Lukas M, Rimarzig B, Sobiella M, Krause M, Baumann M, Bütof R, Enghardt W. Precise image-guided irradiation of small animals: a flexible non-profit platform. Phys Med Biol 2016; 61:3084-108. [DOI: 10.1088/0031-9155/61/8/3084] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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[Small animal image-guided radiotherapy: A new era for preclinical studies]. Cancer Radiother 2016; 20:43-53. [PMID: 26856635 DOI: 10.1016/j.canrad.2015.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 08/03/2015] [Accepted: 08/05/2015] [Indexed: 12/11/2022]
Abstract
Preclinical external beam radiotherapy irradiations used to be delivered with a static broad beam. To promote the transfer from animal to man, the preclinical treatment techniques dedicated to the animal have been optimized to be similar to those delivered to patients in clinical practice. In this context, preclinical irradiators have been developed. Due to the small sizes of the animals, and the irradiation beams, the scaling to the small animal dimensions involves specific problems. Reducing the size and energy of the irradiation beams require very high technical performance, especially for the mechanical stability of the irradiator and the spatial resolution of the imaging system. In addition, the determination of the reference absorbed dose rate must be conducted with a specific methodology and suitable detectors. To date, three systems are used for preclinical studies in France. The aim of this article is to present these new irradiators dedicated to small animals from a physicist point of view, including the commissioning and the quality control.
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Du W, Johnson JL, Jiang W, Kudchadker RJ. On the selection of gantry and collimator angles for isocenter localization using Winston-Lutz tests. J Appl Clin Med Phys 2016; 17:167-178. [PMID: 26894350 PMCID: PMC5690203 DOI: 10.1120/jacmp.v17i1.5792] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 10/07/2015] [Accepted: 10/01/2015] [Indexed: 11/23/2022] Open
Abstract
In Winston-Lutz (WL) tests, the isocenter of a linear accelerator (linac) is determined as the intersection of radiation central axes (CAX) from multiple gantry, collimator, and couch angles. It is well known that the CAX can wobble due to mechanical imperfections of the linac. Previous studies suggested that the wobble varies with gantry and collimator angles. Therefore, the isocenter determined in the WL tests has a profound dependence on the gantry and collimator angles at which CAX are sampled. In this study, we evaluated the systematic and random errors in the iso-centers determined with different CAX sampling schemes. Digital WL tests were performed on six linacs. For each WL test, 63 CAX were sampled at nine gantry angles and seven collimator angles. Subsets of these data were used to simulate the effects of various CAX sampling schemes. An isocenter was calculated from each subset of CAX and compared against the reference isocenter, which was calculated from 48 opposing CAX. The differences between the calculated isocenters and the reference isocenters ranged from 0 to 0.8 mm. The differences diminished to less than 0.2 mm when 24 or more CAX were sampled. Isocenters determined with collimator 0° were vertically lower than those determined with collimator 90° and 270°. Isocenter localization errors in the longitudinal direction (along the axis of gantry rotation) showed a strong dependence on the collimator angle selected. The errors in all directions were significantly reduced when opposing collimator angles and opposing gantry angles were employed. The isocenter localization errors were less than 0.2 mm with the common CAX sampling scheme, which used four cardinal gantry angles and two opposing collimator angles. Reproducibility stud-ies on one linac showed that the mean and maximum variations of CAX during the WL tests were 0.053 mm and 0.30 mm, respectively. The maximal variation in the resulting isocenters was 0.068 mm if 48 CAX were used, or 0.13 mm if four CAX were used. Quantitative results from this study are useful for understanding and minimizing the isocenter uncertainty in WL tests.
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Affiliation(s)
- Weiliang Du
- The University of Texas MD Anderson Cancer Center.
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Brodin NP, Guha C, Tomé WA. Proposal for a Simple and Efficient Monthly Quality Management Program Assessing the Consistency of Robotic Image-Guided Small Animal Radiation Systems. HEALTH PHYSICS 2015; 109:S190-S199. [PMID: 26425981 PMCID: PMC4602164 DOI: 10.1097/hp.0000000000000323] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Modern pre-clinical radiation therapy (RT) research requires high precision and accurate dosimetry to facilitate the translation of research findings into clinical practice. Several systems are available that provide precise delivery and on-board imaging capabilities, highlighting the need for a quality management program (QMP) to ensure consistent and accurate radiation dose delivery. An ongoing, simple, and efficient QMP for image-guided robotic small animal irradiators used in pre-clinical RT research is described. Protocols were developed and implemented to assess the dose output constancy (based on the AAPM TG-61 protocol), cone-beam computed tomography (CBCT) image quality and object representation accuracy (using a custom-designed imaging phantom), CBCT-guided target localization accuracy and consistency of the CBCT-based dose calculation. To facilitate an efficient read-out and limit the user dependence of the QMP data analysis, a semi-automatic image analysis and data representation program was developed using the technical computing software MATLAB. The results of the first 6-mo experience using the suggested QMP for a Small Animal Radiation Research Platform (SARRP) are presented, with data collected on a bi-monthly basis. The dosimetric output constancy was established to be within ±1 %, the consistency of the image resolution was within ±0.2 mm, the accuracy of CBCT-guided target localization was within ±0.5 mm, and dose calculation consistency was within ±2 s (±3%) per treatment beam. Based on these results, this simple quality assurance program allows for the detection of inconsistencies in dosimetric or imaging parameters that are beyond the acceptable variability for a reliable and accurate pre-clinical RT system, on a monthly or bi-monthly basis.
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Affiliation(s)
- N. Patrik Brodin
- Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY 10461, USA
- Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Chandan Guha
- Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY 10461, USA
- Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Wolfgang A. Tomé
- Department of Radiation Oncology, Montefiore Medical Center, Bronx, NY 10461, USA
- Institute for Onco-Physics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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Bache ST, Juang T, Belley MD, Koontz BF, Adamovics J, Yoshizumi TT, Kirsch DG, Oldham M. Investigating the accuracy of microstereotactic-body-radiotherapy utilizing anatomically accurate 3D printed rodent-morphic dosimeters. Med Phys 2015; 42:846-55. [PMID: 25652497 DOI: 10.1118/1.4905489] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE Sophisticated small animal irradiators, incorporating cone-beam-CT image-guidance, have recently been developed which enable exploration of the efficacy of advanced radiation treatments in the preclinical setting. Microstereotactic-body-radiation-therapy (microSBRT) is one technique of interest, utilizing field sizes in the range of 1-15 mm. Verification of the accuracy of microSBRT treatment delivery is challenging due to the lack of available methods to comprehensively measure dose distributions in representative phantoms with sufficiently high spatial resolution and in 3 dimensions (3D). This work introduces a potential solution in the form of anatomically accurate rodent-morphic 3D dosimeters compatible with ultrahigh resolution (0.3 mm(3)) optical computed tomography (optical-CT) dose read-out. METHODS Rodent-morphic dosimeters were produced by 3D-printing molds of rodent anatomy directly from contours defined on x-ray CT data sets of rats and mice, and using these molds to create tissue-equivalent radiochromic 3D dosimeters from Presage. Anatomically accurate spines were incorporated into some dosimeters, by first 3D printing the spine mold, then forming a high-Z bone equivalent spine insert. This spine insert was then set inside the tissue equivalent body mold. The high-Z spinal insert enabled representative cone-beam CT IGRT targeting. On irradiation, a linear radiochromic change in optical-density occurs in the dosimeter, which is proportional to absorbed dose, and was read out using optical-CT in high-resolution (0.5 mm isotropic voxels). Optical-CT data were converted to absolute dose in two ways: (i) using a calibration curve derived from other Presage dosimeters from the same batch, and (ii) by independent measurement of calibrated dose at a point using a novel detector comprised of a yttrium oxide based nanocrystalline scintillator, with a submillimeter active length. A microSBRT spinal treatment was delivered consisting of a 180° continuous arc at 225 kVp with a 20 × 10 mm field size. Dose response was evaluated using both the Presage/optical-CT 3D dosimetry system described above, and independent verification in select planes using EBT2 radiochromic film placed inside rodent-morphic dosimeters that had been sectioned in half. RESULTS Rodent-morphic 3D dosimeters were successfully produced from Presage radiochromic material by utilizing 3D printed molds of rat CT contours. The dosimeters were found to be compatible with optical-CT dose readout in high-resolution 3D (0.5 mm isotropic voxels) with minimal artifacts or noise. Cone-beam CT image guidance was possible with these dosimeters due to sufficient contrast between high-Z spinal inserts and tissue equivalent Presage material (CNR ∼10 on CBCT images). Dose at isocenter measured with optical-CT was found to agree with nanoscintillator measurement to within 2.8%. Maximum dose in line profiles taken through Presage and film dose slices agreed within 3%, with FWHM measurements through each profile found to agree within 2%. CONCLUSIONS This work demonstrates the feasibility of using 3D printing technology to make anatomically accurate Presage rodent-morphic dosimeters incorporating spinal-mimicking inserts. High quality optical-CT 3D dosimetry is feasible on these dosimeters, despite the irregular surfaces and implanted inserts. The ability to measure dose distributions in anatomically accurate phantoms represents a powerful useful additional verification tool for preclinical microSBRT.
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Affiliation(s)
- Steven T Bache
- Duke University Medical Physics Graduate Program, Durham, North Carolina 27705
| | - Titania Juang
- Duke University Medical Physics Graduate Program, Durham, North Carolina 27705
| | - Matthew D Belley
- Duke University Medical Physics Graduate Program, Durham, North Carolina 27705
| | | | | | | | - David G Kirsch
- Duke University Medical Center, Durham, North Carolina 27710
| | - Mark Oldham
- Duke University Medical Center, Durham, North Carolina 27710
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Jeong J, Chen Q, Febo R, Yang J, Pham H, Xiong JP, Zanzonico PB, Deasy JO, Humm JL, Mageras GS. Adaptation, Commissioning, and Evaluation of a 3D Treatment Planning System for High-Resolution Small-Animal Irradiation. Technol Cancer Res Treat 2015; 15:460-71. [PMID: 25948321 DOI: 10.1177/1533034615584522] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 04/01/2015] [Indexed: 01/24/2023] Open
Abstract
Although spatially precise systems are now available for small-animal irradiations, there are currently limited software tools available for treatment planning for such irradiations. We report on the adaptation, commissioning, and evaluation of a 3-dimensional treatment planning system for use with a small-animal irradiation system. The 225-kV X-ray beam of the X-RAD 225Cx microirradiator (Precision X-Ray) was commissioned using both ion-chamber and radiochromic film for 10 different collimators ranging in field size from 1 mm in diameter to 40 × 40 mm(2) A clinical 3-dimensional treatment planning system (Metropolis) developed at our institution was adapted to small-animal irradiation by making it compatible with the dimensions of mice and rats, modeling the microirradiator beam orientations and collimators, and incorporating the measured beam data for dose calculation. Dose calculations in Metropolis were verified by comparison with measurements in phantoms. Treatment plans for irradiation of a tumor-bearing mouse were generated with both the Metropolis and the vendor-supplied software. The calculated beam-on times and the plan evaluation tools were compared. The dose rate at the central axis ranges from 74 to 365 cGy/min depending on the collimator size. Doses calculated with Metropolis agreed with phantom measurements within 3% for all collimators. The beam-on times calculated by Metropolis and the vendor-supplied software agreed within 1% at the isocenter. The modified 3-dimensional treatment planning system provides better visualization of the relationship between the X-ray beams and the small-animal anatomy as well as more complete dosimetric information on target tissues and organs at risk. It thereby enhances the potential of image-guided microirradiator systems for evaluation of dose-response relationships and for preclinical experimentation generally.
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Affiliation(s)
- Jeho Jeong
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Qing Chen
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Robert Febo
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Jie Yang
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Hai Pham
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Jian-Ping Xiong
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Pat B Zanzonico
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Joseph O Deasy
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - John L Humm
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
| | - Gig S Mageras
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA
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Azimi R, Alaei P, Spezi E, Hui SK. Characterization of an orthovoltage biological irradiator used for radiobiological research. JOURNAL OF RADIATION RESEARCH 2015; 56:485-492. [PMID: 25694476 PMCID: PMC4426923 DOI: 10.1093/jrr/rru129] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 12/16/2014] [Accepted: 12/27/2014] [Indexed: 06/01/2023]
Abstract
Orthovoltage irradiators are routinely used to irradiate specimens and small animals in biological research. There are several reports on the characteristics of these units for small field irradiations. However, there is limited knowledge about use of these units for large fields, which are essential for emerging large-field irregular shape irradiations, namely total marrow irradiation used as a conditioning regimen for hematological malignancies. This work describes characterization of a self-contained Orthovoltage biological irradiator for large fields using measurements and Monte Carlo simulations that could be used to compute the dose for in vivo or in vitro studies for large-field irradiation using this or a similar unit. Percentage depth dose, profiles, scatter factors, and half-value layers were measured and analyzed. A Monte Carlo model of the unit was created and used to generate depth dose and profiles, as well as scatter factors. An ion chamber array was also used for profile measurements of flatness and symmetry. The output was determined according to AAPM Task Group 61 guidelines. The depth dose measurements compare well with published data for similar beams. The Monte Carlo-generated depth dose and profiles match our measured doses to within 2%. Scatter factor measurements indicate gradual variation of these factors with field size. Dose rate measured by placing the ion chamber atop the unit's steel plate or solid water indicate enhanced readings of 5 to 28% compared with those measured in air. The stability of output over a 5-year period is within 2% of the 5-year average.
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Affiliation(s)
- Rezvan Azimi
- Department of Radiation Oncology, University of Minnesota, 420 Delaware Street, SE MMC 494, Minneapolis, MN 55455, USA
| | - Parham Alaei
- Department of Radiation Oncology, University of Minnesota, 420 Delaware Street, SE MMC 494, Minneapolis, MN 55455, USA
| | - Emiliano Spezi
- Department of Medical Physics, Velindre Cancer Centre, Velindre Road, CF14 2TL, Cardiff, UK
| | - Susanta K Hui
- Department of Radiation Oncology, University of Minnesota, 420 Delaware Street, SE MMC 494, Minneapolis, MN 55455, USA
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