Peripheral photon and neutron doses from external beam radiotherapy (EBRT) are associated with increased risk of carcinogenesis in the out-of-field organs; thus, dose estimations of secondary radiation are imperative.
Peripheral photon and neutron doses from EBRT of prostate carcinoma were measured in Rando phantom. 6LiF:Mg,Cu,P and 7LiF:Mg,Cu,P glass-rod thermoluminescence dosemeters (TLDs) were inserted in slices of a Rando phantom followed by exposure to 80 Gy with 18-MV photon four-field 3D-CRT technique. The TLDs were calibrated using 6- and 18-MV X-ray beam. Neutron dose equivalents measured with CR-39 etch-track detectors were used to derive readout-to-neutron dose conversion factor for 6LiF:Mg,Cu,P TLDs. Average neutron dose equivalents per 1 Gy of isocentre dose were 3.8±0.9 mSv Gy-1 for thyroid and 7.0±5.4 mSv Gy-1 for colon. For photons, the average dose equivalents per 1 Gy of isocentre dose were 0.2±0.1 mSv Gy-1 for thyroid and 8.1±9.7 mSv Gy-1 for colon. Paired 6LiF:Mg,Cu,P and 7LiF:Mg,Cu,P TLDs can be used to measure photon and neutron doses simultaneously. Organs in close proximity to target received larger doses from photons than those from neutrons whereas distally located organs received higher neutron versus photon dose.
Bezak E, Takam R, Marcu LG. Are you the author?
Department of Medical Physics, Royal Adelaide Hospital, Adelaide, Australia School of Chemistry and Physics, Adelaide University, Adelaide, Australia; Faculty of Science, University of Oradea, Oradea 410087, Romania.
Reference: Radiat Prot Dosimetry. 2015 Jan 5. pii: ncu362.