The Kilovoltage Intrafraction Monitoring Real-Time Prostate Cancer Image Guided Radiation Therapy Technology Journey:...

Stereotactic Body Radiation Therapy (SBRT) schedules for prostate cancer are emerging as a standard treatment approach. However, although high efficacy is achieved in clinical trials, additional efforts at accurate treatment delivery are necessary to maximize the therapeutic ratio in the community setting. Kilovoltage Intrafraction Monitoring (KIM) is a technology developed to address the unmet clinical need of accurate intrafraction motion management without a requirement for additional hardware on standard linear accelerators. This paper describes the journey from bench to bedside of KIM.

The concept of KIM emerged in 2008 in a series of simulations, progressing to phantom experiments commencing in 2010, culminating in the first clinical trial starting in 2014. A series of technical innovations integrating rotational prostate movements, quality assurance, and dynamic multileaf collimator tracking were included within the multi-institutional Trans-Tasman Radiation Oncology Group 15.01 Stereotactic Prostate Adaptive Radiation therapy using KIM clinical trial for prostate SBRT.

Submillimeter accuracy of KIM was observed in simulations, phantom experiments, and clinical trials. The Stereotactic Prostate Adaptive Radiation therapy using KIM trial demonstrated multicenter feasibility of use, a high rate of intrafraction motion triggering a gating event, and a significant dosimetric impact of KIM deployment for target volume coverage. KIM is being made available through commercialization with an industry partner, and through a 300-patient, 10-center clinical trial.

The collaboration between researchers, clinicians, and industry has led to KIM being developed from a concept to clinical trials, enabling the safe delivery of prostate cancer SBRT in the presence of intrafraction motion. This journey provides a template for similar bench-to-bedside translational research.