Premium
Monte Carlo dose characterization of a new 90 Sr / 90 Y source with balloon for intravascular brachytherapy
Author(s) -
Wang Ruqing,
Li X. Allen,
Lobdell John
Publication year - 2003
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 - 10.1118/1.1527673
Subject(s) - brachytherapy , monte carlo method , balloon , dosimetry , point source , electromagnetic shielding , nuclear medicine , materials science , penetration depth , balloon catheter , radioactive source , biomedical engineering , physics , optics , medicine , radiology , mathematics , radiation therapy , surgery , statistics , composite material , detector
Beta emitting source wires or seeds have been adopted in clinical practice of intravascular brachytherapy for coronary vessels. Due to the limitation of penetration depth, this type of source is normally not applicable to treat vessels with large diameter, e.g., peripheral vessel. In the effort to extend application of its beta source for peripheral vessels, Novoste has recently developed a new catheter‐based system, the Corona™90 Sr / 90 Y system. It is a source train of 6 cm length and is jacketed by a balloon. The existence of the balloon increases the penetration of the beta particles and maintains the source within a location away from the vessel wall. Using the EGSnrc Monte Carlo system, we have calculated the two‐dimensional (2‐D) dose rate distribution of the Corona™ system in water for a balloon diameter of 5 mm. The dose rates on the transverse axis obtained in this study are in good agreement with calibration results of the National Institute of Standards and Technology for the same system for balloon diameters of 5 and 8 mm. Features of the 2‐D dose field were studied in detail. The dose parameters based on AAPM TG‐60 protocol were derived. For a balloon diameter of 5 mm, the dose rate at the reference point (defined as r 0 = 4.5 mm , 2 mm from the balloon surface) is found to be 0.010 28 Gy min − 1 mCi − 1 . A new formalism for a better characterization of this long source is presented. Calculations were also performed for other balloon diameters. The dosimetry for this source is compared with a192 Ir source, commonly used for peripheral arteries. In conclusion, we have performed a detailed dosimetric characterization for a new beta source for peripheral vessels. Our study shows that, from dosimetric point of view, the Corona™ system can be used for the treatment of an artery with a large diameter, e.g., peripheral vessel.