Dosimetric characteristics of line 142Pr beta sources in a prostate phantom for potential use in brachytherapy using two different dosimetry techniques

다국어 초록 (Multilingual Abstract)

The study aims to present the dosimetric properties of a novel line 142Pr beta-emitting source in an organ-specific prostate phantom for its potential use in prostate brachytherapy. The line 142Pr sources containing in capillary glass tubes, were produced through 141Pr(n,γ)142Pr reaction at a thermal neutron flux of 2.5x1012 n⋅cm􀀀 2⋅s􀀀 1 in a 250 kW Triga Mark II research reactor. Each tube containing ~100 mg 141Pr (100%), when irradiated for 25 min, resulted in a dose rate of ~2 Gy/h suitable for brachytherapy, even after a decay time of 10–12 h. Dosimetric characterization of line 142Pr sources were performed in terms of source strength, non-uniformity and active source length according to NCS-14, ICRU-72, and AAPM TG-60/TG-149 protocols by using EBT3 radiochromic film and ExradinW1 plastic scintillator detector (PSD). Measurements were conducted both in free-air and in waterequivalent solid phantoms, followed by dose mapping in a patient-specific, 3D printed anthropomorphic pelvic phantom representing prostate (target), bladder, and rectum (organs-at-risk). Although it does not exactly represent a brachytherapy treatment case, the dosimetric results indicate that line 142Pr sources can be used in brachytherapy applications at least as a medium-dose-rate brachytherapy source.
The produced novel line 142Pr beta sources exhibited low dose non-uniformities (0.8–3.7%) and source strengths of approx. 2–3 Gy/h at 10 h post-production. Dose profiles obtained on the prostate phantom indicated a steep beta dose fall-off and favorable dose distributions at OARs. The overall results indicate that line 142Pr beta sources meet the essential dosimetric requirements for brachytherapy sources, and it may serve as a promising candidate for future interstitial prostate applications, pending further pre-clinical evaluation.