Abstract: A system and method for capturing a portal image using a linear accelerator having a multi-leaf collimator (MLC) and an imager allows the portal image field to be automatically clipped using the multi-leaf collimator so that the projection of the portal image field onto the imager falls within the allowed image area of the imager. In this manner, portal images may be obtained in instances where the projection of the portal image field onto the flat-panel imager is larger than an allowed image area of the imager, or where the projection of the portal image field onto the imager is not centered and would extend beyond the allowed image area, so that radiation sensitive electronics outside of the allowed image area are protected from undesirable exposure to radiation.

Abstract: Some embodiments include determination of a first misalignment between an imaging device and an axis of a radiation beam emitted from a treatment head, determination of a rotational misalignment between the imaging device and the treatment head within a plane normal to the axis of the radiation beam, acquisition of an image using the imaging device, and modification of the acquired image based on the determined first misalignment and rotational misalignment. Embodiments may further include determination of a second rotational misalignment between the imaging device and the plane normal to the axis of the radiation beam, and modification of the acquired image based on the determined first misalignment, rotational misalignment and second rotational misalignment.

Abstract: A system includes acquisition of a first image of a first radiation field, at least a portion of the first radiation field comprising radiation attenuated by a device, and the first image including a representation of first scatter radiation generated during acquisition of the first image, acquisition of a second image of a second radiation field, at least a portion of the second radiation field comprising radiation attenuated by a volume corresponding to the device, and the second image including a representation of second scatter radiation generated during acquisition of the second image, and modification of the second image based on the first image to compensate for the second scatter radiation.

Abstract: A system and method for capturing a portal image using a linear accelerator having a multi-leaf collimator (MLC) and an imager allows the portal image field to be automatically clipped using the multi-leaf collimator so that the projection of the portal image field onto the imager falls within the allowed image area of the imager. In this manner, portal images may be obtained in instances where the projection of the portal image field onto the flat-panel imager is larger than an allowed image area of the imager, or where the projection of the portal image field onto the imager is not centered and would extend beyond the allowed image area, so that radiation sensitive electronics outside of the allowed image area are protected from undesirable exposure to radiation.

Abstract: Some embodiments include determination of a first misalignment between an imaging device and an axis of a radiation beam emitted from a treatment head, determination of a rotational misalignment between the imaging device and the treatment head within a plane normal to the axis of the radiation beam, acquisition of an image using the imaging device, and modification of the acquired image based on the determined first misalignment and rotational misalignment. Embodiments may further include determination of a second rotational misalignment between the imaging device and the plane normal to the axis of the radiation beam, and modification of the acquired image based on the determined first misalignment, rotational misalignment and second rotational misalignment.

Abstract: A system includes acquisition of a first image of a first radiation field, at least a portion of the first radiation field comprising radiation attenuated by a device, and the first image including a representation of first scatter radiation generated during acquisition of the first image, acquisition of a second image of a second radiation field, at least a portion of the second radiation field comprising radiation attenuated by a volume corresponding to the device, and the second image including a representation of second scatter radiation generated during acquisition of the second image, and modification of the second image based on the first image to compensate for the second scatter radiation.