Novel adaptive beam-dependent margins for additional OAR sparing.
View/ Open
Date
2018-10-29Author
Tsang, HS
Kamerling, CP
Ziegenhein, P
Nill, S
Oelfke, U
Type
Journal Article
Metadata
Show full item recordAbstract
Margins are employed in radiotherapy treatment planning to mitigate the dosimetric effects of geometric uncertainties for the clinical target volume (CTV). Unfortunately, whilst the use of margins can increase the probability that sufficient dose is delivered to the CTV, it can also result in delivering high dose of radiation to surrounding organs at risk (OARs). We expand on our previous work on beam-dependent margins and propose a novel adaptive margin concept, where margins are moulded away from selected OARs for better OAR-high-dose sparing, whilst maintaining similar dose coverage probability to the CTV. This, however, comes at a cost of a larger irradiation volume, and thus can negatively impact other structures. We investigate the impact of the adaptive margin concept when applied to prostate radiotherapy treatments, and compare treatment plans generated using our beam-dependent margins without adaptation, with adaption from the rectum and with adaptation from both the rectum and bladder. Five prostate patients were used in this planning study. All plans achieved similar dose coverage probability, and were able to ensure at least 90% population coverage with the target receiving at least 95% of the prescribed dose to [Formula: see text]. We observed overall better high-dose sparing to OARs that were considered when using the adapted beam-dependent PTVs, with the degree of sparing dependent on both the number of OARs under consideration as well as the relative position between the CTV and the OARs.
Collections
Subject
Rectum
Humans
Prostatic Neoplasms
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted
Probability
Uncertainty
Radiometry
Male
Radiotherapy, Intensity-Modulated
Organs at Risk
Research team
Radiotherapy Physics Modelling
Language
eng
Date accepted
2018-10-05
License start date
2018-10-29
Citation
Physics in medicine and biology, 2018, 63 (21), pp. 215019 - ?
Publisher
IOP PUBLISHING LTD