Dosimetry study of strontium-90/yttrium source for intravascular brachytherapy

Jikkang Son, Purdue University


A Monte Carlo simulation for radiation dosimetry and an experimental verification of the simulation were developed for a Novoste 90Sr/Y source in intravascular brachytherapy. Dose uniformity change due to source curvature was investigated by simulating linear and curved sources using MCNP Monte Carlo code. Simulation results were benchmarked against radiochromic film exposures in a solid water phantom. The agreement between the simulation and experiment was within 8% at the prescription point of 2 mm. The simulation and experiment showed that a curved source with a radius of curvature of 1.43 cm resulted in a significant dose non-uniformity at 2 mm of ±8.6% and ±10.4% respectively. An analytical model to calculate dose distribution around the 90Sr/Y linear source was developed. A discrepancy between the Monte Carlo result and the analytical model was 1.6% at 2 mm. The analytical model is a quick and accurate method for computing the dose distribution around intravascular brachytherapy sources. A possible dosimetric advantage of a combined source of beta emitter (90Sr/Y) and gamma-emitter (137Cs) in one catheter-based source train was investigated to combine the best of features from the beta-emitter and gamma-emitter. With the combined source the dose uniformity was improved compared to the beta only source. However, the dose to the healthy tissue was increased in the combined source. The effect of the curvature and issues concerning the current dose delivery methodology is addressed. This research established reliable dose calculation methods for intravascular brachytherapy, and investigated a possible optimization method for effective treatment.




Choi, Purdue University.

Subject Area

Oncology|Radiology|Biomedical research

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