Prog Med Phys.  2020 Sep;31(S1):S5.

Detector-based Dose Verification System for Phantom-less Delivery Quality Assurance in Tomothearpy

• Han MC
• Han MC
• Chang KH
• Chang KH
• Kim J
• Kim J
• Han SC
• Han SC
• Park K
• Park K
• Kim DW
• Kim DW
• Kim HJ
• Kim HJ
• Kim JS
• Kim JS

Abstract

Purpose
We developed a new technique, named TomoCHECK, to perform phantom-less delivery quality assurance (DQA) system in Tomothearpy using an exit detector and software-based QA platform.
Methods
TomoCHECK was designed to generate a new digital imaging and communication in medicine (DICOM) dataset based on leaf open time (LOT)-measured detector data and to provide phantom-less DQA results using independent dose calculation platform. To evaluate the developed program, 20 phantom-less DQAs were performed using TomoCHECK with Mobius3D software, and the results were compared to conventional phantom-based QA results.
Results
The results show no significant difference between TomoCHECK and conventional QA results within our acceptance criteria, excluding one case; the exception shall be raised due to the difference in the dose calculation algorithm in Mobius3D. From extra assessment, TomoCHECK successfully detected a failed case and showed approximately the same trends as the conventional approach.
Conclusions
We have developed a new DQA system called TomoCHECK, which could perform phantom-less QA for Tomotherapy using the detector data. From our results, it was confirmed that TomoCHECK could be possible to provide reliable DQA results with 3D dose verification from heterogeneous patient geometry treated in Tomotherapy.

Keyword

Tomotherapy; Delivery quality assurance; Phantom-less quality assurance; Leaf open time; Mobius3D