Tolerance levels of mass density for CT number calibration in photon radiation therapy.

Tolerance levels of mass density for CT number calibration in photon radiation therapy. J Appl Clin Med Phys. 2019 May 13;: Authors: Nakao M, Ozawa S, Yogo K, Miura H, Yamada K, Hosono F, Hayata M, Miki K, Nakashima T, Ochi Y, Kawahara D, Morimoto Y, Yoshizaki T, Nozaki H, Habara K, Nagata Y Abstract Computed tomography (CT) data are required to calculate the dose distribution in a patient's body. Generally, there are two CT number calibration methods for commercial radiotherapy treatment planning system (RTPS), namely CT number-relative electron density calibration (CT-RED calibration) and CT number-mass density calibration (CT-MD calibration). In a previous study, the tolerance levels of CT-RED calibration were established for each tissue type. The tolerance levels were established when the relative dose error to local dose reached 2%. However, the tolerance levels of CT-MD calibration are not established yet. We established the tolerance levels of CT-MD calibration based on the tolerance levels of CT-RED calibration. In order to convert mass density (MD) to relative electron density (RED), the conversion factors were determined with adult reference computational phantom data available in the International Commission on Radiological Protection publication 110 (ICRP-110). In order to validate the practicability of the conversion factor, the relative dose error and the dose linearity were validated with multiple RTPSes and dose calcu...
Source: Journal of Applied Clinical Medical Physics - Category: Physics Authors: Tags: J Appl Clin Med Phys Source Type: research