Mauro Carrara1, Chiara Tenconi2, Giulio Rossi2, Marta Borroni3, Annamaria Cerrotta4, Simone Grisotto2, Davide Cusumano2, Brigida Pappalardi5, Dean Cutajar6, Marco Petasecca6, Michael Lerch6, Grazia Gambarini7, Carlo Fallai4, Anatoly Rosenfeld6, Emanuele Pignoli3. 1. Medical Physics Unit, Dept. of Diagnostic Imaging and Radiotherapy, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Prostate Cancer Program, Scientific Director's Office, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. Electronic address: mauro.carrara@istitutotumori.mi.it. 2. Medical Physics Unit, Dept. of Diagnostic Imaging and Radiotherapy, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 3. Medical Physics Unit, Dept. of Diagnostic Imaging and Radiotherapy, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Prostate Cancer Program, Scientific Director's Office, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 4. Prostate Cancer Program, Scientific Director's Office, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Radiation Oncology 2 Unit, Dept. of Diagnostic Imaging and Radiotherapy, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 5. Radiation Oncology 2 Unit, Dept. of Diagnostic Imaging and Radiotherapy, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. 6. Centre for Medical Radiation Physics, University of Wollongong, Australia. 7. National Institute of Nuclear Physics INFN, Milan, Italy.
Abstract
BACKGROUND AND PURPOSE: To study if MOSkin detectors coupled to a trans-rectal ultrasound (TRUS) probe may be used for in vivo dosimetry on the rectal wall surface during US-based HDR prostate brachytherapy and to quantify possible discrepancies between planned and delivered doses. MATERIALS AND METHODS: MOSkins are a specific type of MOSFET dosimeter optimized to measure dose in steep dose gradients on interfaces. Two MOSkins were assembled on a TRUS probe used for on-line treatment planning. Measurements of the dose to the rectal wall were performed over 18 treatment sessions and compared to the doses calculated on the pre-treatment plan (DPRE) and reconstructed on post-treatment images (DPOST). RESULTS: Averages of the absolute differences between MOSkin readings and DPRE, MOSkin readings and DPOST and DPRE and DPOST were 6.7 ± 5.1%, 3.6 ± 1.9% and 6.3 ± 4.7%, respectively. Agreement between measurements and DPOST was significantly better than between measurements and DPRE (p=0.002) and DPRE and DPOST (p=0.004). Discrepancy between DPOST and DPRE correlated with the time required for treatment planning. CONCLUSION: MOSkin dosimeters integrated to the TRUS probe proved to be an accurate instrument for measuring the dose delivered to the rectal wall in HDR prostate brachytherapy. The delivered doses may differ significantly from those calculated in the treatment plan.
BACKGROUND AND PURPOSE: To study if MOSkin detectors coupled to a trans-rectal ultrasound (TRUS) probe may be used for in vivo dosimetry on the rectal wall surface during US-based HDR prostate brachytherapy and to quantify possible discrepancies between planned and delivered doses. MATERIALS AND METHODS: MOSkins are a specific type of MOSFET dosimeter optimized to measure dose in steep dose gradients on interfaces. Two MOSkins were assembled on a TRUS probe used for on-line treatment planning. Measurements of the dose to the rectal wall were performed over 18 treatment sessions and compared to the doses calculated on the pre-treatment plan (DPRE) and reconstructed on post-treatment images (DPOST). RESULTS: Averages of the absolute differences between MOSkin readings and DPRE, MOSkin readings and DPOST and DPRE and DPOST were 6.7 ± 5.1%, 3.6 ± 1.9% and 6.3 ± 4.7%, respectively. Agreement between measurements and DPOST was significantly better than between measurements and DPRE (p=0.002) and DPRE and DPOST (p=0.004). Discrepancy between DPOST and DPRE correlated with the time required for treatment planning. CONCLUSION: MOSkin dosimeters integrated to the TRUS probe proved to be an accurate instrument for measuring the dose delivered to the rectal wall in HDR prostate brachytherapy. The delivered doses may differ significantly from those calculated in the treatment plan.
Authors: Kimberley Legge; Peter B Greer; Daryl J O'Connor; Lee Wilton; Matthew Richardson; Perry Hunter; Alex Wilfert; Jarad Martin; Anatoly Rosenfeld; Dean Cutajar Journal: Radiat Oncol Date: 2017-02-27 Impact factor: 3.481
Authors: Gabriel P Fonseca; Jacob G Johansen; Ryan L Smith; Luc Beaulieu; Sam Beddar; Gustavo Kertzscher; Frank Verhaegen; Kari Tanderup Journal: Phys Imaging Radiat Oncol Date: 2020-09-28