Quantitative analysis of brass compensators for commissioning of the Pinnacle planning system for IMRT

Abstract

Brass compensators for beam modulation present an alternative method for IMRT treatment planning to traditional dynamic leaf modulation. In this work, we present a detailed method to commission the Pinnacle treatment planning system for IMRT using brass compensators. Beam attenuation from various brass thicknesses were measured using an ion chamber, as well as a MapCHECK device, for a representative seven‐field IMRT plan. We show that Pinnacle's parameters for compensators can be optimized to match the measured results while still maintaining the original open‐beam model. Only Pinnacle's modified scatter factor and brass density value were adjusted. Beam attenuation in several brass slabs were optimized by minimizing a χ2 function of measured and modeled data for several depths in solid water. Using MapCHECK, Pinnacle's parameters were optimized by minimizing the number of points that fail during a gamma analysis of seven fields in a typical IMRT plan. Our results show that Pinnacle's 10X beam is best modeled using a brass density of 7.8 g/cm3 and a modified scatter factor of 0.1 cm−1.PACS numbers: 87.56.N, 87.56.ng, 87.55.kh, 87.55.de

Technical note: A comparison of in‐house 3D‐printed and commercially available patient‐specific skin collimators for use with electron beam therapy

“…Brass has been used for other applications in radiation oncology, such as spatially fractionated radiation therapy, bolus, and compensators. [9][10][11] This study provides a comprehensive comparative analysis of 3D-printed Bronzefill (3DPB) and machined brass (MB) skin shields for electron radiotherapy treatments. We present the dosimetric characteristics of the skin shields.…”

“…The controlled manufacturing process of brass lends itself to systematic quality assurance measures, enhancing its appeal in clinical applications. Brass has been used for other applications in radiation oncology, such as spatially fractionated radiation therapy, bolus, and compensators 9–11 …”

“…Brass has been used for other applications in radiation oncology, such as spatially fractionated radiation therapy, bolus, and compensators. 9 , 10 , 11 …”