Title: Prostate brachytherapy intraoperative dosimetry using a combination of radiographic seed localization with a C-arm and deformed ultrasound prostate contours
Abstract: <h2>Abstract</h2><h3>Purpose</h3> The purpose of the study was to assess the feasibility of performing intraoperative dosimetry for permanent prostate brachytherapy by combining transrectal ultrasound (TRUS) and fluoroscopy/cone beam CT [CBCT] images and accounting for the effect of prostate deformation. <h3>Methods and Materials</h3> 13 patients underwent TRUS and multiview two-dimensional fluoroscopic imaging partway through the implant, as well as repeat fluoroscopic imaging with the TRUS probe inserted and retracted, and finally three-dimensional CBCT imaging at the end of the implant. The locations of all the implanted seeds were obtained from the fluoroscopy/CBCT images and were registered to prostate contours delineated on the TRUS images based on a common subset of seeds identified on both image sets. Prostate contours were also deformed, using a finite-element model, to take into account the effect of the TRUS probe pressure. Prostate dosimetry parameters were obtained for fluoroscopic and CBCT-dosimetry approaches and compared with the standard-of-care Day-0 postimplant CT dosimetry. <h3>Results</h3> High linear correlation (R<sup>2</sup> > 0.8) was observed in the measured values of prostate <i>D</i><sub>90%</sub>, <i>V</i><sub>100%</sub>, and <i>V</i><sub>150%</sub>, between the two intraoperative dosimetry approaches. The prostate <i>D</i><sub>90%</sub> and <i>V</i><sub>100%</sub> obtained from intraoperative dosimetry methods were in agreement with the postimplant CT dosimetry. Only the prostate <i>V</i><sub>150%</sub> was on average 4.1% (<i>p</i>-value <0.05) higher in the CBCT-dosimetry approach and 6.7% (<i>p</i>-value <0.05) higher in postimplant CT dosimetry compared with the fluoroscopic dosimetry approach. Deformation of the prostate by the ultrasound probe appeared to have a minimal effect on prostate dosimetry. <h3>Conclusions</h3> The results of this study have shown that both of the proposed dosimetric evaluation approaches have potential for real-time intraoperative dosimetry.
Publication Year: 2020
Publication Date: 2020-09-01
Language: en
Type: article
Indexed In: ['crossref', 'pubmed']
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Cited By Count: 2
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