Open AccessDefinition and visualisation of regions of interest in post‐prostatectomy image‐guided intensity modulated radiotherapy
Author(s) -
Bell Linda J,
Cox Jennifer,
Eade Thomas,
Rinks Marianne,
Kneebone Andrew
Publication year - 2014
Publication title -
journal of medical radiation sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 18
eISSN - 2051-3909
pISSN - 2051-3895
DOI - 10.1002/jmrs.58
Subject(s) - medicine , soft tissue , computer science , cone beam computed tomography , image registration , nuclear medicine , computer vision , radiology , computed tomography , image (mathematics)
Abstract Introduction Standard post‐prostatectomy radiotherapy ( PPRT ) image verification uses bony anatomy alignment. However, the prostate bed ( PB ) moves independently of bony anatomy. Cone beam computed tomography ( CBCT ) can be used to soft tissue match, so radiation therapists ( RT s) must understand pelvic anatomy and PPRT clinical target volumes ( CTV ). The aims of this study are to define regions of interest ( ROI ) to be used in soft tissue matching image guidance and determine their visibility on planning CT ( PCT ) and CBCT . Methods Published CTV guidelines were used to select ROI s. The PCT scans ( n = 23) and CBCT scans ( n = 105) of 23 post‐prostatectomy patients were reviewed. Details on ROI identification were recorded. Results Eighteen patients had surgical clips. All ROI s were identified on PCT s at least 90% of the time apart from mesorectal fascia ( MF ) (87%) due to superior image quality. When surgical clips are present, the seminal vesicle bed ( SVB ) was only seen in 2.3% of CBCT s and MF was unidentifiable. Most other structures were well identified on CBCT . The anterior rectal wall ( ARW ) was identified in 81.4% of images and penile bulb ( PB ) in 68.6%. In the absence of surgical clips, the MF and SVB were always identified; the ARW was identified in 89.5% of CBCT s and PB in 73.7%. Conclusions Surgical clips should be used as ROI s when present to define SVB and MF . In the absence of clips, SVB , MF and ARW can be used. RT s must have a strong knowledge of soft tissue anatomy and PPRT CTV to ensure coverage and enable soft tissue matching.