Characterization of Compton-scatter imaging with an analytical simulation method.

Characterization of Compton-scatter imaging with an analytical simulation method.
Phys Med Biol. 2017 Dec 15;:
Authors: Jones KC, Redler G, Templeton A, Bernard D, Turian JV, Chu JCH
Abstract
By collimating the photons scattered when a megavoltage therapy beam interacts with the patient, a Compton-scatter image may be formed without the delivery of extra dose. To characterize and assess the potential of the technique, an analytical model for simulating scatter images was developed and validated against Monte Carlo (MC). For three phantoms, the scatter images collected during irradiation with a 6 MV flattening-filter-free therapy beam were simulated. Images, profiles, and spectra were compared for different phantoms and different irradiation angles. The proposed analytical method simulates accurate scatter images up to 1000 times faster than MC. Minor differences between MC and analytical simulated images are attributed to limitations in the isotropic superposition/convolution algorithm used to analytically model multiple-order scattering. For a detector placed at 90<sup>o</sup> relative to the treatment beam, the simulated scattered photon energy spectrum peaks at 140-220 keV, and 40-50% of the photons are the result of multiple scattering. The high energy photons originate at the beam entrance. Increasing the angle between source and detector increases the average energy of the collected photons and decre...

Source: Physics in Medicine and Biology - December 15, 2017 Category: Physics Authors: Jones KC, Redler G, Templeton A, Bernard D, Turian JV, Chu JCH Tags: Phys Med Biol Source Type: research