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Independent validation of a system for real-time localization of the prostate during motion tracking radiotherapy

Stefansson, Klara LU (2024) PHYL01 20232
Department of Physics
Abstract
Intrafractional prostate motion during external beam radiotherapy of prostate
tumors has been reported as a limiting factor in accurate treatment delivery. Technology for real-time image-guided radiotherapy has been introduced for tracking
and for compensating prostate motion during treatment and could allow for reduced
target margins. This project investigated the geometrical accuracy of Radixact Synchrony, an image-guided Multi Leaf Collimator-tracking system, in its detection of intrafractional translational prostate motion by comparison with Kilovoltage Intrafractional Monitoring (KIM), an independent retrospective model for trajectory estimation using 2D-kVs. KIM’s and Synchrony’s estimations of prostate trajectories in a phantom... (More)
Intrafractional prostate motion during external beam radiotherapy of prostate
tumors has been reported as a limiting factor in accurate treatment delivery. Technology for real-time image-guided radiotherapy has been introduced for tracking
and for compensating prostate motion during treatment and could allow for reduced
target margins. This project investigated the geometrical accuracy of Radixact Synchrony, an image-guided Multi Leaf Collimator-tracking system, in its detection of intrafractional translational prostate motion by comparison with Kilovoltage Intrafractional Monitoring (KIM), an independent retrospective model for trajectory estimation using 2D-kVs. KIM’s and Synchrony’s estimations of prostate trajectories in a phantom reproducing previously recorded tumor trajectories were compared to the known phantom trajectories. For clinical validation in patients, KIM
retrospectively estimated the clinical tumor trajectories at a total of 41 fractions for seven prostate cancer patients using the 2D-kV images acquired by Synchrony during treatment. The KIM-estimated trajectories were then compared to the trajectories estimated by Synchrony. Synchrony’s ability to detect uncertainty in its estimations, as reflected in the built-in uncertainty parameter Potential difference, was analyzed. The results showed that KIM’s estimations of phantom trajectories were accurate, establishing its validity for verifying Synchrony’s estimations in patients. Estimation differences between KIM and Synchrony mainly appeared in conjunction with rapid movement in the form of oscillations in Synchrony’s estimation of the left-right prostate motion and a delay in Synchrony’s estimation of the anterior-posterior prostate motion. Errors were transient and reflected in an increase of Potential difference, implying a low impact on delivered dose and a capability of the system to detect estimation uncertainties. The results lead to the conclusion that Synchrony accurately estimates the intrafractional translational motion and could be used to reduce target margins during treatment. (Less)
Please use this url to cite or link to this publication:
author
Stefansson, Klara LU
supervisor
organization
course
PHYL01 20232
year
type
M2 - Bachelor Degree
subject
language
English
id
9148450
date added to LUP
2024-02-15 09:16:37
date last changed
2024-02-15 09:16:37
@misc{9148450,
  abstract     = {{Intrafractional prostate motion during external beam radiotherapy of prostate
tumors has been reported as a limiting factor in accurate treatment delivery. Technology for real-time image-guided radiotherapy has been introduced for tracking
and for compensating prostate motion during treatment and could allow for reduced
target margins. This project investigated the geometrical accuracy of Radixact Synchrony, an image-guided Multi Leaf Collimator-tracking system, in its detection of intrafractional translational prostate motion by comparison with Kilovoltage Intrafractional Monitoring (KIM), an independent retrospective model for trajectory estimation using 2D-kVs. KIM’s and Synchrony’s estimations of prostate trajectories in a phantom reproducing previously recorded tumor trajectories were compared to the known phantom trajectories. For clinical validation in patients, KIM
retrospectively estimated the clinical tumor trajectories at a total of 41 fractions for seven prostate cancer patients using the 2D-kV images acquired by Synchrony during treatment. The KIM-estimated trajectories were then compared to the trajectories estimated by Synchrony. Synchrony’s ability to detect uncertainty in its estimations, as reflected in the built-in uncertainty parameter Potential difference, was analyzed. The results showed that KIM’s estimations of phantom trajectories were accurate, establishing its validity for verifying Synchrony’s estimations in patients. Estimation differences between KIM and Synchrony mainly appeared in conjunction with rapid movement in the form of oscillations in Synchrony’s estimation of the left-right prostate motion and a delay in Synchrony’s estimation of the anterior-posterior prostate motion. Errors were transient and reflected in an increase of Potential difference, implying a low impact on delivered dose and a capability of the system to detect estimation uncertainties. The results lead to the conclusion that Synchrony accurately estimates the intrafractional translational motion and could be used to reduce target margins during treatment.}},
  author       = {{Stefansson, Klara}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Independent validation of a system for real-time localization of the prostate during motion tracking radiotherapy}},
  year         = {{2024}},
}