Abstract: In radiotherapy, a high quality imaging array may be placed after the patient and opposite the radiation source to be used during radiation treatment to verify operation of a shutter system or similar device and/or to compute dose delivered to the patient. A model of the patient may be used and inverted in order to estimate values of energy fluence prior to absorption by the patient and overlapping of the various radiation beams passing through the patient. A test pattern of shutter excitation to illuminate a single ray at a time provides a simple method of obtaining the necessary model. The dose from this test pattern may be subtracted from the subsequent radiation treatment so as to provide limited or no increase in total dose to the patient.

Abstract: Radiotherapy controlling, treatment sinograms may be directly modified to correct for real time motion of patients or portions of patients resulting from physiological or other activity. Precalculated partial sinograms representing treatments of portions of a patient may be assembled to obtain a treatment sinogram for the entire patient without delay from conventional planning software. The partial sinograms are modified as representations of their corresponding portions and manipulated to conform to the particular dimensions of an actual patient. This constructed sinogram may be used directly or as a starting point for iterative optimization.