A feasibility study on the use of tomotherapy megavoltage computed tomography images for palliative patient treatment planning

Abstract

Dedicated rapid access palliative radiation therapy improves patients’ access to care, allowing more timely treatment which would positively impact on quality of life. The TomoTherapy (Accuray, Sunnyvale, CA) system provides megavoltage (MV) fan-beam computed tomography (FBCT) as the image guidance technique, and a module called “statRT” that allows the use of these MV FBCT images for direct planning. The possibility of using this imaging modality for palliative radiotherapy treatment planning is assessed against accepted planning CT standards by performing tests following AAPM TG 66 and an end-to-end measurement. Results have shown that MV FBCT images acquired by TomoTherapy are of sufficient quality for the purpose of target delineation and dose calculation for palliative treatments. Large image noise and extended scan acquisition time are the two main drawbacks, so this imaging modality should only be used for palliative treatments at areas with well-known, easily distinguishable, and relatively immobile targets such as spine and whole brain.

Characterization of an advanced cone beam CT (CBCT) reconstruction algorithm used for dose calculation on Varian Halcyon linear accelerators

“…The capability of performing dose calculations on the CBCT scans produced by the on-board kV imaging system has been assessed by multiple studies [2][3][4][5][6][7] using various methods. The use of CBCT for dose calculation has gained substantial research interests due to its vast clinical applications, such as offline adaptive radiotherapy [6], dose summation analysis [7], and rapid access to palliative radiotherapy for departments that do not have dedicated CT scanners [8].…”