Abstract: Techniques for background subtraction in computed tomography include determining voxels in a slice of interest in a three dimensional computed tomography scan of the interior of a body based on a first set of measurements of radiation transmitted through the body. Based on the first set of measurements, a first background image for radiation transmitted through the body in a first direction is determined without the effects of the voxels in the slice of interest. A current image is determined based on a different current measurement of radiation transmitted through the body in the first direction. A first difference is determined between the current image and the first background image. The result is a high contrast image in the slice of interest even from a single current projection image.

Abstract: Techniques for improving treatment delivered to a target site in a patient include delivering a treatment from a treatment delivery device to a target site in a patient supported by a patient support structure. During the delivery of treatment, a state of the patient is measured to produce real-time measurement data. Measuring the state is non-invasive; and the measured state is a correlated surrogate for position of the target site. Compensating movement data is determined based on the real-time measurement data to cause the target site to maintain a particular spatial relationship with the treatment delivery device. Either the treatment delivery device, or the support structure, or both, are moved based on the compensating movement data. When the delivery device alone is moved, the correlation between measured state and target site is based on partial least squares applied to pre-treatment measurements of both.

Abstract: Techniques for improving treatment delivered to a target site in a patient include delivering a treatment from a treatment delivery device to a target site in a patient supported by a patient support structure. During the delivery of treatment, a state of the patient is measured to produce real-time measurement data. Measuring the state is non-invasive; and the measured state is a correlated surrogate for position of the target site. Compensating movement data is determined based on the real-time measurement data to cause the target site to maintain a particular spatial relationship with the treatment delivery device. Either the treatment delivery device, or the support structure, or both, are moved based on the compensating movement data. When the delivery device alone is moved, the correlation between measured state and target site is based on partial least squares applied to pre-treatment measurements of both.