Hendrik Westendorp1, Tonnis T Nuver2, Carel J Hoekstra3, Marinus A Moerland4, André W Minken2. 1. Department of Medical Physics, Radiotherapiegroep Behandellocatie Deventer, Deventer, The Netherlands. Electronic address: r.westendorp@radiotherapiegroep.nl. 2. Department of Medical Physics, Radiotherapiegroep Behandellocatie Deventer, Deventer, The Netherlands; Department of Radiation Oncology, Radiotherapiegroep Behandellocatie Deventer, Deventer, The Netherlands. 3. Department of Radiation Oncology, Radiotherapiegroep Behandellocatie Deventer, Deventer, The Netherlands. 4. Department of Radiation Oncology, University Medical Center Utrecht, Utrecht, The Netherlands.
Abstract
PURPOSE: We sought to identify the intraoperative displacement patterns of seeds and to evaluate the correlation of intraoperative dosimetry with day 30 for permanent prostate brachytherapy. METHODS AND MATERIALS: We analyzed the data from 699 patients. Intraoperative dosimetry was acquired using transrectal ultrasonography (TRUS) and C-arm cone beam computed tomography (CBCT). Intraoperative dosimetry (minimal dose to 40%-95% of the volume [D40-D95]) was compared with the day 30 dosimetry for both modalities. An additional edema-compensating comparison was performed for D90. Stranded seeds were linked between TRUS and CBCT using an automatic and fast linking procedure. Displacement patterns were analyzed for each seed implantation location. RESULTS: On average, an intraoperative (TRUS to CBCT) D90 decline of 10.6% ± 7.4% was observed. Intraoperative CBCT D90 showed a greater correlation (R(2) = 0.33) with respect to Day 30 than did TRUS (R(2) = 0.17). Compensating for edema, the correlation increased to 0.41 for CBCT and 0.38 for TRUS. The mean absolute intraoperative seed displacement was 3.9 ± 2.0 mm. The largest seed displacements were observed near the rectal wall. The central and posterior seeds showed less caudal displacement than lateral and anterior seeds. Seeds that were implanted closer to the base showed more divergence than seeds close to the apex. CONCLUSIONS: Intraoperative CBCT D90 showed a greater correlation with the day 30 dosimetry than intraoperative TRUS. Edema seemed to cause most of the systematic difference between the intraoperative and day 30 dosimetry. Seeds near the rectal wall showed the most displacement, comparing TRUS and CBCT, probably because of TRUS probe-induced prostate deformation.
PURPOSE: We sought to identify the intraoperative displacement patterns of seeds and to evaluate the correlation of intraoperative dosimetry with day 30 for permanent prostate brachytherapy. METHODS AND MATERIALS: We analyzed the data from 699 patients. Intraoperative dosimetry was acquired using transrectal ultrasonography (TRUS) and C-arm cone beam computed tomography (CBCT). Intraoperative dosimetry (minimal dose to 40%-95% of the volume [D40-D95]) was compared with the day 30 dosimetry for both modalities. An additional edema-compensating comparison was performed for D90. Stranded seeds were linked between TRUS and CBCT using an automatic and fast linking procedure. Displacement patterns were analyzed for each seed implantation location. RESULTS: On average, an intraoperative (TRUS to CBCT) D90 decline of 10.6% ± 7.4% was observed. Intraoperative CBCT D90 showed a greater correlation (R(2) = 0.33) with respect to Day 30 than did TRUS (R(2) = 0.17). Compensating for edema, the correlation increased to 0.41 for CBCT and 0.38 for TRUS. The mean absolute intraoperative seed displacement was 3.9 ± 2.0 mm. The largest seed displacements were observed near the rectal wall. The central and posterior seeds showed less caudal displacement than lateral and anterior seeds. Seeds that were implanted closer to the base showed more divergence than seeds close to the apex. CONCLUSIONS: Intraoperative CBCT D90 showed a greater correlation with the day 30 dosimetry than intraoperative TRUS. Edema seemed to cause most of the systematic difference between the intraoperative and day 30 dosimetry. Seeds near the rectal wall showed the most displacement, comparing TRUS and CBCT, probably because of TRUS probe-induced prostate deformation.
Authors: Junghoon Lee; Omar Y Mian; Yi Le; Hee Joon Bae; E Clif Burdette; Theodore L DeWeese; Jerry L Prince; Daniel Y Song Journal: Radiother Oncol Date: 2017-06-21 Impact factor: 6.280
Authors: Geoffrey V Martin; Thomas J Pugh; Usama Mahmood; Rajat J Kudchadker; Jihong Wang; Teresa L Bruno; Tharakeswara Bathala; Steven J Frank Journal: Brachytherapy Date: 2017-03-09 Impact factor: 2.362
Authors: Tanmay Singh; Junghoon Lee; Marianna Zahurak; Hee Joon Bae; Tamey Habtu; Robert Hobbs; Yi Le; Everette C Burdette; Daniel Y Song Journal: Pract Radiat Oncol Date: 2021-03-13