Publication: Patient dosimetry of <sup>177</sup>Lu-PSMA I&T in metastatic prostate cancer treatment: the experience in Thailand
Issued Date
2021-11-01
Resource Type
ISSN
18646433
09147187
09147187
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2-s2.0-85111252287
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Mahidol University
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SCOPUS
Bibliographic Citation
Annals of Nuclear Medicine. Vol.35, No.11 (2021), 1193-1202
Suggested Citation
Kotchakorn Chatachot, Shuichi Shiratori, Tawatchai Chaiwatanarat, Kitiwat Khamwan Patient dosimetry of <sup>177</sup>Lu-PSMA I&T in metastatic prostate cancer treatment: the experience in Thailand. Annals of Nuclear Medicine. Vol.35, No.11 (2021), 1193-1202. doi:10.1007/s12149-021-01659-8 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/77744
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Title
Patient dosimetry of <sup>177</sup>Lu-PSMA I&T in metastatic prostate cancer treatment: the experience in Thailand
Abstract
Purpose: This study aimed to determine the radiation dosimetry for 177Lu-PSMA imaging and therapy (I&T) in Thai patients who were treated for metastatic prostate cancer. Methods: Whole-body planar images acquired at immediately, 4 and 24 h after 177Lu-PSMA I&T injection (range 4.44–8.51 GBq) were collected from 12 treatment cycles of 8 prostate cancer patients. Region of interests (ROIs) were manually contoured on the whole-body, liver, spleen, urinary bladder, lacrimal glands, parotid, and submandibular glands to determine time-integrated activity (TIA) in source organs and fitted time-activity curves using mono-exponential extrapolation. The S values calculated utilizing non-uniform rational B-splines (NURBS) computational phantoms were extracted from the OLINDA/EXM v. 2.0 to calculate the absorbed dose coefficient in target organs according to the Medical Internal Radiation Dose (MIRD) scheme. The absorbed doses to bone marrow were estimated using the planar two-compartment image-based method by separating the high-uptake and low-uptake compartment. The spherical model was used to calculate the lacrimal gland absorbed doses. Results: Mean absorbed dose coefficients to the kidneys, bone marrow, liver, urinary bladder, spleen, lacrimal glands, parotid, and submandibular glands were 0.81 ± 0.24, 0.02 ± 0.01, 0.13 ± 0.10, 0.27 ± 0.25, 0.16 ± 0.07, 3.62 ± 1.78, 0.21 ± 0.14, and 0.09 ± 0.07 Gy/GBq, respectively. Dose constraints for the kidneys (23 Gy) and bone marrow (2 Gy) were not reached in any patients. The absorbed dose in lacrimal glands calculated by the NURBS computational phantoms was slightly lower than the calculation based on the Cristy–Eckerman computational phantoms using OLINDA/EXM v. 1.0 by 6.37 ± 0.14%. Conclusion: Dosimetry results in this study suggested that 177Lu-PSMA I&T treatment with higher activities and more cycles is possible without the risk of damaging normal organs in prostate cancer patients.