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Quality Assurance for the Clinical Implementation of Kilovoltage Intrafraction Monitoring (KIM) in the TROG 17.03 Liver Ablative Radiotherapy with KIM (LARK) Multi-Institutional Clinical Trial

C Sengupta1*, D Nguyen2, T Moodie 3, S Alnaghy4, R O'Brien1, P J Keall1, (1) ACRF Image X Institute, The University of Sydney, AU, (2) School of Biomedical Engineering, University of Technology, Sydney, AU, (3) Crown Princess Mary Cancer Centre, Westmead, AU, (4)Centre for Medical Radiation Physics, University of Wollongong, AU


(Sunday, 7/12/2020)   [Eastern Time (GMT-4)]

Room: AAPM ePoster Library

Purpose: Kilovoltage Intrafraction Monitoring (KIM) is a real-time tumor motion monitoring system for radiotherapy treatments. KIM uses the information from the gantry mounted kV imager to monitor tumor motions without any additional equipment. Recently, KIM has been piloted in a clinical trial (LARK, NCT02984566) for liver SBRT treatments. The purpose of this work was to perform quality assurance (QA) tests at multiple institutions for the safe clinical implementation of KIM for LARK clinical trials.

Methods: Using the adapted AAPM TG147 QA guidelines, three LARK specific QA tests were performed: (1) Static localization accuracy, (2) Dynamic localization accuracy, (3) Treatment interruption accuracy. The static localization test was performed by shifting a phantom in left-right (LR), superior-inferior (SI) and anterior-posterior (AP) directions using the treatment couch and KIM was used to estimate the magnitude and directions of the static shifts. The dynamic localization test and treatment interruption test for KIM were performed by placing the phantom on a 6-DoF motion platform that replicated patient-measured liver traces including large SI and AP, transient, breath-hold, and, erratic trajectories. The tolerances for all the three QA tests were that the mean difference and the standard deviation between the programmed trajectory and the measured data were less than 1 mm and 2 mm respectively.

Results: For the static test, the mean difference and standard deviation between the known shifts and KIM predicted shifts were found to be 0.09 mm and 0.3 mm respectively. For both the dynamic localization and treatment interruption tests, the mean differences and the standard deviations were found to be less than 1 mm and 2 mm respectively for all the liver trajectories.

Conclusion: During all the QA tests for LARK clinical trials, the errors were found to be within the tolerance level ensuring the safe implementation of KIM for LARK clinical trials.

Funding Support, Disclosures, and Conflict of Interest: This work was funded by Cancer Australia grant. With regard to conflict of interest, author Paul J. Keall is the inventor of the licensed and the authors Paul J. Keall and Doan Trang Nguyen are the inventors of unlicensed patents related to the KIM technology.


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