Monte Carlo and experimental dosimetry of an {sup 125}I brachytherapy seed
- Department of Radiation Oncology, Beth Israel Medical Center, New York, New York 10003 (United States)
We have performed a comprehensive dosimetric characterization of the Oncura{sup TM} model 6711 {sup 125}I seed using both experimental [LiF thermoluminscent dosimetry (TLD)] and theoretical (Monte Carlo photon transport) methods. In addition to determining the dosimetric parameters of the 6711, this report quantified: (1) the angular dependence of LiF TLD energy response functions for both point and volume detectors in water, poly(methylmethacrylate), and solid water media; and (2) the contribution of underlying geometric uncertainties to the overall uncertainty of Monte Carlo derived dosimetric parameters according to the National Institute of Standards and Technology Report 1297 methodology. The theoretical value for the dose rate constant in water was 0.942 cGy U{sup -1} h{sup -1}{+-}1.76% [combined standard uncertainty (CSU) with coverage factor k=1] and the experimental value was 0.971 cGy U{sup -1} h{sup -1}{+-}6.1%. Agreement between experimental and theoretical radial dose function values was well within the k=1 CSU, while agreement between experimental and theoretical anisotropy function values was within the k=1 CSU only after incorporating the use of polar angle-dependent energy response functions. The angular dependence of the relative energy response was found to have a complex and significant dependence on measurement medium and internal geometry of the source.
- OSTI ID:
- 20853835
- Journal Information:
- Medical Physics, Vol. 33, Issue 12; Other Information: DOI: 10.1118/1.2388158; (c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
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