Evaluating a potential technique with local optical flow vectors for automatic organ-at-risk (OAR) intrusion detection and avoidance during radiotherapy.

Evaluating a potential technique with local optical flow vectors for automatic organ-at-risk (OAR) intrusion detection and avoidance during radiotherapy.
Phys Med Biol. 2019 Jun 28;:
Authors: Teo PT, Guo K, Ahmed B, Alayoubi N, Kehler K, Fontaine G, Sasaki D, Pistorius S
Abstract
Various techniques of deep inspiration breath hold (DIBH) have been used to mitigate the likelihood and risk of exposing the heart, an organ-at-risk (OAR) for unintended radiation during left breast radiotherapy. However, issues of reproducibility of these techniques warrant further investigation into the feasibility of detecting the intrusion of an OAR into the treatment field during intra-fractional treatment delivery. The increase of high-dose, low-fraction radiotherapy treatments makes it important to immediately adapt treatment once an organ-at-risk (OAR) is detected in the treatment field. This proof-of-concept implementation includes an algorithm that detects and tracks the motion at the edges of a treatment field and a control algorithm that adapts the treatment aperture according to the motion detected. In accordance to the AAPM Task-Group (TG-132) report, image registration techniques should be verified with virtual and physical phantoms prior to clinical application. Since most OARs move as a result of respiration-induced motion, we have used a lung phantom to generate images of a generic OAR intruding into a treatment field with known velocity. T...

Source: Physics in Medicine and Biology - June 27, 2019 Category: Physics Authors: Teo PT, Guo K, Ahmed B, Alayoubi N, Kehler K, Fontaine G, Sasaki D, Pistorius S Tags: Phys Med Biol Source Type: research