Journal article
Effectiveness of Rotating Shield Brachytherapy for Prostate Cancer Dose Escalation and Urethral Sparing
International journal of radiation oncology, biology, physics, Vol.102(5), pp.1543-1550
12/01/2018
DOI: 10.1016/j.ijrobp.2018.07.2015
PMCID: PMC6363898
PMID: 30092333
Abstract
Purpose
To compare single-fraction 153Gd-based rotating shield brachytherapy (RSBT) for prostate cancer with conventional 192Ir-based high-dose-rate brachytherapy (HDR-BT) in a planning study that radiobiologically accounts for dose rate and relative biological effectiveness. RSBT was used for planning target volume (PTV) dose escalation without increasing urethral dose for monotherapy, or for urethral sparing without decreasing PTV dose as a boost to external beam radiation therapy.
Methods and Materials
Twenty-six patients were studied. PTV doses were expressed as equivalent dose delivered in 2 Gy fractions (EQD2), accounting for relative biological effectiveness (1.00 for 192Ir and 1.15 for 153Gd), dose protraction (114-minute repair half-time), and tumor dose response (α/β of 3.41 Gy). HDR-BT dose was prescribed such that 90% of the PTV received 110% of the prescription dose of 19 Gy for dose escalation and 15 Gy for urethral sparing, corresponding to EQD290% values (minimum EQD2 to the hottest 90% of the PTV) of 93.9 GyEQD2 and 60.7 GyEQD2, respectively. Twenty 90.95 GBq 153Gd RSBT sources and one 370 GBq 192Ir HDR-BT source were modeled.
Results
For dose escalation with fresh sources, RSBT increased PTV EQD290% by 42.5% ± 8.4% (average ± standard deviation) without increasing urethral D10%, with treatment times of 216.8 ± 28.9 minutes versus 15.1 ± 2.1 minutes. After 1 half-life (240.4 days for 153Gd and 73.8 days for 192Ir), EQD290% increased 20.5% ± 9.1%. For urethral sparing with fresh sources, RSBT decreased urethral D10% by 26.0% ± 3.4% without decreasing PTV EQD290%, with treatment times of 133.6 ± 16.5 minutes versus 12.0 ± 1.7 minutes. After 1 half-life, urethral D10% decreased 20.2% ± 4.8%.
Conclusions
RSBT can increase PTV EQD90% or decrease urethral D10% relative to HDR-BT at the cost of increased treatment time. Source aging reduces RSBT benefit, but RSBT remains theoretically superior to HDR-BT by >20% after 1 half-life has elapsed.
Details
- Title: Subtitle
- Effectiveness of Rotating Shield Brachytherapy for Prostate Cancer Dose Escalation and Urethral Sparing
- Creators
- Quentin Adams - Department of Radiation Oncology, University of Iowa, Iowa City, Iowa. Electronic address: quentin-adams@uiowa.eduKarolyn M Hopfensperger - Department of Biomedical Engineering, University of Iowa, Iowa City, IowaYusung Kim - Department of Radiation Oncology, University of Iowa, Iowa City, IowaXiaodong Wu - Department of Radiation Oncology, University of Iowa, Iowa City, Iowa; Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IowaWeiyu Xu - Department of Electrical and Computer Engineering, University of Iowa, Iowa City, IowaHemant Shukla - OSF Saint Francis Medical Center, Peoria, IllinoisJames McGee - OSF Saint Francis Medical Center, Peoria, IllinoisJoseph M Caster - Department of Radiation Oncology, University of Iowa, Iowa City, IowaRyan T Flynn - Department of Radiation Oncology, University of Iowa, Iowa City, Iowa
- Resource Type
- Journal article
- Publication Details
- International journal of radiation oncology, biology, physics, Vol.102(5), pp.1543-1550
- DOI
- 10.1016/j.ijrobp.2018.07.2015
- PMID
- 30092333
- PMCID
- PMC6363898
- NLM abbreviation
- Int J Radiat Oncol Biol Phys
- ISSN
- 0360-3016
- eISSN
- 1879-355X
- Publisher
- Elsevier Inc; United States
- Grant note
- R41 CA210737 / NCI NIH HHS P30 CA086862 / NCI NIH HHS R01 EB020665 / NIBIB NIH HHS
- Language
- English
- Date published
- 12/01/2018
- Academic Unit
- Electrical and Computer Engineering; Radiation Oncology
- Record Identifier
- 9984047850402771
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