Abstract: An apparatus for identifying and quantifying image distortions within a patient magnetic resonance image set comprises a structure of magnetic resonance compatible materials with a high level of rigidity, where the structure is configured to cover the whole image volume of the brain region of the patient and sized to fit within a brain magnetic resonance coil when worn by a patient. A plurality of magnetic resonance fiducial markers is placed on the structure, thereby permitting the measurement of three-dimensional distances between the markers when the patient undergoes a magnetic resonance imaging procedure. Also presented is a process for identifying and quantifying image distortions within a patient magnetic resonance image set using the apparatus where the geometrical distortion is quantified and compared with a set threshold or a standard image.

Abstract: Linear accelerator (“linac”) downtime invariably impacts delivery of patients' scheduled treatments. Transferring a patient's treatment to an available linac is a common practice. Transferring a VMAT plan from a linac equipped with a standard-definition MLC to one equipped with a higher definition MLC is practical and routine in clinics with multiple MLC-equipped linacs. However, the reverse transfer presents a challenge because the high-definition MLC aperture shapes must be adapted for delivery with the lower definition device. An efficient method to adapt VMAT plans originally designed for a high-definition MLC to a standard definition MLC is disclosed herein. The dosimetric results of the present adaptation method are presented for head-and-neck, brain, lung and prostate VMAT plans. The delivery of the adapted plans was verified using standard phantom measurements.

Abstract: Linear accelerator (“linac”) downtime invariably impacts delivery of patients' scheduled treatments. Transferring a patient's treatment to an available linac is a common practice. Transferring a VMAT plan from a linac equipped with a standard-definition MLC to one equipped with a higher definition MLC is practical and routine in clinics with multiple MLC-equipped linacs. However, the reverse transfer presents a challenge because the high-definition MLC aperture shapes must be adapted for delivery with the lower definition device. An efficient method to adapt VMAT plans originally designed for a high-definition MLC to a standard definition MLC is disclosed herein. The dosimetric results of the present adaptation method are presented for head-and-neck, brain, lung and prostate VMAT plans. The delivery of the adapted plans was verified using standard phantom measurements.