Journal article
Interstitial rotating shield brachytherapy for prostate cancer
Medical physics (Lancaster), Vol.41(5), pp.051703-n/a
05/2014
DOI: 10.1118/1.4870441
PMID: 24784369
Abstract
Purpose:
To present a novel needle, catheter, and radiation source system for interstitial rotating shield brachytherapy (I-RSBT) of the prostate. I-RSBT is a promising technique for reducing urethra, rectum, and bladder dose relative to conventional interstitial high-dose-rate brachytherapy (HDR-BT).
Methods:
A wire-mounted 62 GBq153Gd source is proposed with an encapsulated diameter of 0.59 mm, active diameter of 0.44 mm, and active length of 10 mm. A concept model I-RSBT needle/catheter pair was constructed using concentric 50 and 75 μm thick nickel-titanium alloy (nitinol) tubes. The needle is 16-gauge (1.651 mm) in outer diameter and the catheter contains a 535 μm thick platinum shield. I-RSBT and conventional HDR-BT treatment plans for a prostate cancer patient were generated based on Monte Carlo dose calculations. In order to minimize urethral dose, urethral dose gradient volumes within 0–5 mm of the urethra surface were allowed to receive doses less than the prescribed dose of 100%.
Results:
The platinum shield reduced the dose rate on the shielded side of the source at 1 cm off-axis to 6.4% of the dose rate on the unshielded side. For the case considered, for the same minimum dose to the hottest 98% of the clinical target volume (D
98%), I-RSBT reduced urethral D
0.1cc below that of conventional HDR-BT by 29%, 33%, 38%, and 44% for urethral dose gradient volumes within 0, 1, 3, and 5 mm of the urethra surface, respectively. Percentages are expressed relative to the prescription dose of 100%. For the case considered, for the same urethral dose gradient volumes, rectum D
1cc was reduced by 7%, 6%, 6%, and 6%, respectively, and bladder D
1cc was reduced by 4%, 5%, 5%, and 6%, respectively. Treatment time to deliver 20 Gy with I-RSBT was 154 min with ten 62 GBq 153Gd sources.
Conclusions:
For the case considered, the proposed153Gd-based I-RSBT system has the potential to lower the urethral dose relative to HDR-BT by 29%–44% if the clinician allows a urethral dose gradient volume of 0–5 mm around the urethra to receive a dose below the prescription. A multisource approach is necessary in order to deliver the proposed 153Gd-based I-RSBT technique in reasonable treatment times.
Details
- Title: Subtitle
- Interstitial rotating shield brachytherapy for prostate cancer
- Creators
- Quentin E Adams - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Jinghzu Xu - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Elizabeth K Breitbach - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Xing Li - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Shirin A Enger - Medical Physics Unit, McGill University, 1650 Cedar Ave, Montreal, Quebec H3G 1A4, CanadaWilliam R Rockey - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Yusung Kim - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Xiaodong Wu - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242Ryan T Flynn - Department of Radiation Oncology, University of Iowa, 200 Hawkins Drive, Iowa City, Iowa 52242
- Resource Type
- Journal article
- Publication Details
- Medical physics (Lancaster), Vol.41(5), pp.051703-n/a
- DOI
- 10.1118/1.4870441
- PMID
- 24784369
- NLM abbreviation
- Med Phys
- ISSN
- 0094-2405
- eISSN
- 2473-4209
- Number of pages
- 11
- Language
- English
- Date published
- 05/2014
- Academic Unit
- Electrical and Computer Engineering; Radiation Oncology
- Record Identifier
- 9984046917902771
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