Imaging dose of Varian Halcyon by radiophotoluminescent glass dosimeter

Cone beam computed tomography (CBCT) is the most used imaging technique for image-guided radiation therapy. The Varian Halcyon (Varian Medical Systems, Palo Alto, CA, USA) necessitates daily imaging before starting patient treatment. This study aims to compare the radiation doses of normal organs across all available kV-CBCT protocols on the Varian Halcyon.

Measurements were conducted using radiophotoluminescent glass dosimeters (RPLGD) placed into the Alderson Rando phantom that was positioned to the specific anatomical region (head, thorax, breast, pelvis). The CBCT was scanned using preset protocols without adjusting the parameters.

The average organ dose per scan for the head, thorax, breast and pelvis were 3.04 ± 0.77 (1.39–4.56), 9.20 ± 3.17 (5.66–16.69), 1.44 ± 0.40 (0.89–2.20) and 28.88 ± 4.66 (25.15–37.25) mGy, respectively.

The maximum organ dose in each region for a preset protocol during the treatment range did not exceed 5% of the prescribed dose in each body part following guidelines line the AAPM Task Group 180.