Author/Authors :
Malekzadeh, Etesam Department of Medical Physics - Faculty of Medical Sciences - Tarbiat Modares University, Tehran, Iran , Rajabi, Hossein Department of Medical Physics - Faculty of Medical Sciences - Tarbiat Modares University, Tehran, Iran , Fiorina, Elisa National Institute of Nuclear Physics - Section of Torino, Torino, Italy , Kalantari, Faraz Department of Radiation Oncology - University of Arkansas for Medical Sciences - Little Rock, Arkansas, USA Abstract
Abstract :
Introduction: Gamma cameras are proposed for online range verification and treatment monitoring in proton therapy. An Analytical formula was derived and validated for sensitivity of a slit collimator based on the photon fluence concept.
Methods: Fluence formulation was generalized for photons distribution function and solved for high-energy point sources. The effect of the collimator slit size and source off-axis position on the sensitivity of the collimator were included in the formula.
Results: The analytically calculated sensitivities of the slit collimator were in good agreement with Monte Carlo results according to the Bland-Altman agreement test and Pearson correlation (r =0.998) statistical analysis with . The mean relative error between calculated sensitivities with the derived formula and Monte Carlo was up to 0.8%. Moreover, we found that under certain conditions, the established formula is converted to the Anger equation for the pinhole collimator.
Conclusion: The analytical formula developed in this research can estimate the slit collimator sensitivity with an acceptable accuracy. The derived closed-form sensitivity formula can be applied in KE collimator design and optimization studies.
