Dose correction in lung for HDR breast brachytherapy
- PMID: 23349652
- PMCID: PMC3552632
- DOI: 10.5114/jcb.2012.29367
Dose correction in lung for HDR breast brachytherapy
Abstract
Purpose: To evaluate the dosimetric impact of lung tissue in Ir-192 APBI.
Material and methods: In a 40 × 40 × 40 cm(3) water tank, an Accelerated Partial Breast Irradiation (APBI) brachytherapy balloon inflated to 4 cm diameter was situated directly below the center of a 30 × 30 × 1 cm(3) solid water slab. Nine cm of solid water was stacked above the 1 cm base. A parallel plate ion chamber was centered above the base and ionization current measurements were taken from the central HDR source dwell position for channels 1, 2, 3 and 5 of the balloon. Additional ionization data was acquired in the 9 cm stack at 1 cm increments. A comparable data set was also measured after replacing the 9 cm solid water stack with cork slabs. The ratios of measurements in the two phantoms were calculated and compared to predicted results of a commercial treatment planning system.
Results: Lower dose was measured in the cork within 1 cm of the cork/solid water interface possibly due to backscatter effects. Higher dose was measured beyond 1 cm from the cork/solid water interface, increasing with path length up to 15% at 9 cm depth in cork. The treatment planning system did not predict either dose effect.
Conclusions: This study investigates the dosimetry of low density material when the breast is treated with Ir-192 brachytherapy. HDR dose from Ir-192 in a cork media is shown to be significantly different than in unit density media. These dose differences are not predicted in most commercial brachytherapy planning systems. Empirical models based on measurements could be used to estimate lung dose associated with HDR breast brachytherapy.
Keywords: HDR; dosimetry; lung; partial breast irradiation.
Figures




References
-
- Dragun AE, Harper JL, Olyejar SE, et al. The use of adjuvant high-dose-rate breast brachytherapy in patients with collagen vascular disease: a collaborative experience. Brachytherapy. 2011;10:121–127. - PubMed
-
- Strauss JB, Dickler A. Accelerated partial breast irradiation utilizing balloon brachytherapy techniques. Radiother Oncol. 2009;91:157–165. - PubMed
-
- Richardson SL, Pino R. Dosimetric effects of an air cavity for the SAVI™ partial breast irradiation applicator. Med Phys. 2010;37:3919–3926. - PubMed
-
- Cuttino LW, Todor D, Rosu M, et al. A comparison of skin and chest wall dose delivered with multicatheter, Contura multilumen balloon, and MammoSite breast brachytherapy. Int J Radiat Oncol Biol Phys. 2011;79:34–38. - PubMed
LinkOut - more resources
Full Text Sources