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Monte Carlo dosimetry of a tandem positioned beta‐emitting intravascular brachytherapy source train
Author(s) -
Wallace Steven A.,
Schumer Wendy,
Horrigan Mark
Publication year - 2002
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1461845
Subject(s) - dosimetry , brachytherapy , monte carlo method , nuclear medicine , imaging phantom , physics , medicine , biomedical engineering , radiology , radiation therapy , mathematics , statistics
Prevention of restenosis following interventional coronary procedures with catheter based beta‐emitting sources is currently under clinical trial investigations. Systems utilizing fixed length source trains limit the clinician's ability to increase the radiation source length as required. A technique known as “pull back” is used when the segment of artery requiring radiation is longer than the available fixed length source train. In this instance, tandem positioning of the fixed length source is used to treat the longer length of artery. The aim of this study was to examine the dosimetry of the junction region associated with pull back treatments using a commercially available90 Sr / Y catheter based intravascular brachytherapy source train. Dose profiles were calculated, using the Monte Carlo code MCNP4B , at radial distances of 1.5, 2.0, and 2.5 mm for pull back techniques using 2.5 mm overlapping, abutting, and 2.5 mm spaced source trains. Results at the protocol prescription radius of 2 mm showed a junction dose elevated 61% above prescription for 2.5 mm overlapping source trains. For 2.5 mm spaced trains, this figure falls to 64% below prescription dose. In contrast, abutted source trains exhibited only a 1% depression below prescription dose in the junction region. The reference point dose rate per unit activity of this source was found to be consistent with previous studies.