Cone-beam CT-based adaptive planning improves permanent prostate brachytherapy dosimetry: An analysis of 1266 patients
Westendorp, Hendrik; Hoekstra, Carel J.; Immerzeel, Jos J.; Van De Pol, Sandrine M.G.; Niël, Charles G.H.J.; Kattevilder, Robert A.J.; Nuver, Tonnis T.; Minken, André W.; Moerland, Marinus A.
(2017) Medical Physics, volume 44, issue 4, pp. 1257 - 1267
(Article)
Abstract
PURPOSE: To evaluate adaptive planning for permanent prostate brachytherapy and to identify the prostate regions that needed adaptation. METHODS AND MATERIALS: After the implantation of stranded seeds, using real-time intraoperative planning, a transrectal ultrasound (TRUS)-scan was obtained and contoured. The positions of seeds were determined on a C-arm cone-beam computed
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tomography (CBCT)-scan. The CBCT-scan was registered to the TRUS-scan using fiducial gold markers. If dose coverage on the combined image-dataset was inadequate, an intraoperative adaptation was performed by placing remedial seeds. CBCT-based intraoperative dosimetry was analyzed for the prostate (D90, V100, and V150) and the urethra (D30). The effects of the adaptive dosimetry procedure for Day 30 were separately assessed. RESULTS: We analyzed 1266 patients. In 17.4% of the procedures, an adaptation was performed. Without the dose contribution of the adaptation Day 30 V100 would be < 95% for half of this group. On Day 0, the increase due to the adaptation was 11.8 ± 7.2% (1SD) for D90 and 9.0 ± 6.4% for V100. On Day 30, we observed an increase in D90 of 12.3 ± 6.0% and in V100 of 4.2 ± 4.3%. For the total group, a D90 of 119.6 ± 9.1% and V100 of 97.7 ± 2.5% was achieved. Most remedial seeds were placed anteriorly near the base of the prostate. CONCLUSION: CBCT-based adaptive planning enables identification of implants needing adaptation and improves prostate dose coverage. Adaptations were predominantly performed near the anterior base of the prostate.
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Keywords: adaptive dosimetry, adaptive radiotherapy, brachytherapy, I-125, prostate, Radiotherapy Dosage, Intraoperative Period, Radiotherapy Planning, Computer-Assisted/methods, Humans, Male, Prostatic Neoplasms/diagnostic imaging, Cone-Beam Computed Tomography, Radiometry, Brachytherapy, Biophysics, Radiology Nuclear Medicine and imaging, Journal Article
ISSN: 0094-2405
Publisher: AAPM - American Association of Physicists in Medicine
Note: Publisher Copyright: © 2017 The Authors. Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.
(Peer reviewed)