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A microdosimetry model of kidney by GATE Monte Carlo simulation using a nonuniform activity distribution in digital phantom of nephron. Nucl Med Commun 2020; 41:110-119. [PMID: 31764596 DOI: 10.1097/mnm.0000000000001112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES As the main pathway for the clearance of radiopharmaceutical from the body, kidney is a dose-limiting organ in medical application of radionuclides. Because of its unique physiology, radioactivity is seen to concentrate on kidney nonuniformly. This nonuniformity can be considered in nephron microstructures. A microdosimetry model of kidney is necessary to include the nonuniform distribution in internal radiation dosimetry. METHOD Implementing the microdosimetry model requires, first, a geometry phantom of nephrons. Stylized phantoms cannot distribute activities inside nephron compartments nonuniformly. A phantom of nephron was generated by a preliminary three-dimensional graphic model and was converted to a proper format of digital phantom. The phantom was fed to GATE Monte Carlo toolkits. Simulations were performed and S-values for five radionuclides (Tc-99m, In-111, Lu-177, Ac-225 and Bi-212) were calculated and compared with corresponding results published in the literature derived with a stylized phantom of nephron. Activity was distributed nonuniformly according to the kinetics of two mainly used diagnostic tracers (diethylenetriaminepetaacetate and ethylenedicysteine) and absorbed dose of nephron cells were calculated. RESULTS A good correlation was shown between the generated phantom microdosimetry model and stylized model and revealed the phantom can be used for future microdosimetry studies of kidney to evaluate radiobiological effects of internal radiation from various diagnostic and therapeutic radiopharmaceuticals. Absorbed dose of cells for nonuniform distribution showed that some cells in a nephron compartment receive higher dose than (more than two-fold) that of compartment average dose. CONCLUSION Average dose of nephron is not a reliable parameter for nephrotoxicity evaluation.
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Price E, Robinson AP, Cullen DM, Tipping J, Calvert N, Hamilton D, Oldfield C, Page E, Pietras B, Smith A. Improving molecular radiotherapy dosimetry using anthropomorphic calibration. Phys Med 2019; 58:40-46. [PMID: 30824148 DOI: 10.1016/j.ejmp.2019.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 12/10/2018] [Accepted: 01/17/2019] [Indexed: 11/17/2022] Open
Abstract
The optimised delivery of Molecular Radiotherapy requires individualised calculation of absorbed dose to both targeted lesions and neighbouring healthy tissue. To achieve this, accurate quantification of the activity distribution in the patient by external detection is vital. METHODS This work extends specific anatomy-related calibration to true organ shapes. A set of patient-specific 3D printed organ inserts based on a diagnostic CT scan was produced, comprising the liver, spleen and both kidneys. The inserts were used to calculate patient-specific calibration factors for 177Lu. These calibration factors were compared with previously reported calibration factors for corresponding organ models based on the Cristy and Eckerman phantom series and for a comparably sized sphere. Monte Carlo calculations of the patient-specific radiation dose were performed for comparison with current clinical dosimetry methods for these data. RESULTS Patient-specific calibration factors are shown to be dependent on the volume, shape and position of the organ containing activity with a corresponding impact on the calculation of the dose to the patient. The impact of organ morphology on calculated dose is reduced when the dominant contributor to dose is beta particles. This is due to the small range of beta particles in tissue. Overestimations of recovered activity and hence dose of up to 135% are observed. CONCLUSION For accurate quantification to be performed calibration factors accounting for organ size, shape and position must be used. Such quantification is vital if accurate, patient-specific dosimetry is to be achieved.
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Affiliation(s)
- Emlyn Price
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom; Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom.
| | - Andrew P Robinson
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom; National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom
| | - David M Cullen
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Jill Tipping
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom
| | - Nick Calvert
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom
| | - David Hamilton
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom
| | - Christopher Oldfield
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Emma Page
- Christie Medical Physics and Engineering (CMPE), The Christie NHS Foundation Trust, Wilmslow Road, Manchester M20 4BX, United Kingdom; Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Ben Pietras
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - Andrew Smith
- Schuster Laboratory, School of Physics and Astronomy, The University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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Bagheri M, Parach AA, Razavi-Ratki SK, Nafisi-Moghadam R, Jelodari MA. PATIENT-SPECIFIC DOSIMETRY FOR PEDIATRIC IMAGING OF 99mTc-DIMERCAPTOSUCCINIC ACID WITH GATE MONTE CARLO CODE. RADIATION PROTECTION DOSIMETRY 2018; 178:213-222. [PMID: 28981712 DOI: 10.1093/rpd/ncx101] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 07/12/2017] [Indexed: 06/07/2023]
Abstract
In this study, radiation absorbed dose of 99mTc-dimercaptosuccinic acid (DMSA) in critical organs was calculated using Monte Carlo simulation. Ten child patients with genitourinary abnormalities were imaged using a series of planar, SPECT and MRI, after injection with 99mTc-DMSA. Patient-specific organ segmentation was performed on MRI and used as input in GATE. Organs with substantial uptake included kidneys, bladder and liver. The mean organ absorbed dose coefficients (mGy/MBq) were 0.063, 0.058, 0.018, 0.016, 0.013 and 0.010 for the right kidney, left kidney, bones, urinary bladder wall, liver and gonads, respectively. The absorbed dose coefficients in the remainder of the body was 0.012 mGy/MBq. The authors implemented an image-based Monte Carlo method for patient-specific 3D absorbed dose calculation. This study also demonstrates the possibility to obtain patient-specific attenuation map from MRI to be used for the simulations of radiation transport and energy deposition in phantom using Monte Carlo methods.
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Affiliation(s)
- Mahmoud Bagheri
- Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Ali Asghar Parach
- Department of Medical Physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Seid Kazem Razavi-Ratki
- Department of Radiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Reza Nafisi-Moghadam
- Department of Radiology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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Fallahpoor M, Abbasi M, Asghar Parach A, Kalantari F. The importance of BMI in dosimetry of 153Sm-EDTMP bone pain palliation therapy: A Monte Carlo study. Appl Radiat Isot 2017; 124:1-6. [PMID: 28284122 DOI: 10.1016/j.apradiso.2017.02.044] [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: 05/21/2016] [Revised: 01/19/2017] [Accepted: 02/27/2017] [Indexed: 10/20/2022]
Abstract
Using digital phantoms as an atlas compared to acquiring CT data for internal radionuclide dosimetry decreases patient overall radiation dose and reduces the required analysis effort and time for organ segmentation. The drawback is that the phantom may not match exactly with the patient. We assessed the effect of varying BMIs on dosimetry results for a bone pain palliation agent, 153Sm-EDTMP. The simulation was done using the GATE Monte Carlo code. Female XCAT phantoms with the following different BMIs were employed: 18.6, 20.8, 22.1, 26.8, 30.3 and 34.7kg/m2. S-factors (mGy/MBq.s) and SAFs (kg-1) were calculated for the dosimetry of the radiation from major source organs including spine, ribs, kidney and bladder into different target organs as well as whole body dosimetry from spine. The differences in dose estimates from different phantoms compared to those from the phantom with BMI of 26.8kg/m2 as the reference, were calculated for both gamma and beta radiations. The relative differences (RD) of the S-factors or SAFs from the values of reference phantom were calculated. RDs greater than 10% and 100% were frequent in radiations to organs for photon and beta particles, respectively. The relative differences in whole body SAFs from the reference phantom were 15.4%, 7%, 4.2%, -9.8% and -1.4% for BMIs of 18.6, 20.8, 22.1, 30.3 and 34.7kg/m2, respectively. The differences in whole body S-factors for the phantoms with BMIs of 18.6, 20.8, 22.1, 30.3 and 34.7kg/m2 were 39.5%, 19.4%, 8.8%, -7.9% and -4.3%, respectively. The dosimetry of the gamma photons and beta particles changes substantially with the use of phantoms with different BMIs. The change in S-factors is important for dose calculation and can change the prescribed therapeutic dose of 153Sm-EDTMP. Thus a phantom with BMI better matched to the patient is suggested for therapeutic purposes where dose estimates closer to those in the actual patient are required.
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Affiliation(s)
- Maryam Fallahpoor
- Department of Nuclear Medicine, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehrshad Abbasi
- Department of Nuclear Medicine, Vali-Asr Hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
| | - Ali Asghar Parach
- Department of medical physics, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Faraz Kalantari
- Department of Radiation Oncology, UT Southwestern Medical Center, Dallas, TX 75235, United Stated
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Villoing D, Marcatili S, Garcia MP, Bardiès M. Internal dosimetry with the Monte Carlo code GATE: validation using the ICRP/ICRU female reference computational model. Phys Med Biol 2017; 62:1885-1904. [DOI: 10.1088/1361-6560/62/5/1885] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Ghahraman Asl R, Nasseri S, Parach AA, Zakavi SR, Momennezhad M, Davenport D. Monte Carlo and experimental internal radionuclide dosimetry in RANDO head phantom. AUSTRALASIAN PHYSICAL & ENGINEERING SCIENCES IN MEDICINE 2015; 38:465-72. [DOI: 10.1007/s13246-015-0367-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Accepted: 07/28/2015] [Indexed: 11/28/2022]
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