Abstract: A system or use with a radiotherapy system includes a scanner for producing images of at least one object within an imaging volume, a radiotherapy apparatus including a source of therapeutic radiation adapted to deliver a beam of radiation into the at least one object, a treatment planning system for controlling the source so as to deliver radiation in accordance with a predetermined plan for treating a patient and with the images of the at least one object, and at least one device within and/or adjacent to the imaging volume. The at least one device comprises at least one first marker which is visible to the scanner and at least one MR second marker which is visible to an MR scanner. The system further comprises a database containing data including the markers associated with the at least one device and at least its geometric and density characteristics.

Abstract: A system or use with a radiotherapy system includes a scanner for producing images of at least one object within an imaging volume, a radiotherapy apparatus including a source of therapeutic radiation adapted to deliver a beam of radiation into the at least one object, a treatment planning system for controlling the source so as to deliver radiation in accordance with a predetermined plan for treating a patient and with the images of the at least one object, and at least one device within and/or adjacent to the imaging volume. The at least one device comprises at least one first marker which is visible to the scanner and at least one MR second marker which is visible to an MR scanner. The system further comprises a database containing data including the markers associated with the at least one device and at least its geometric and density characteristics.

Abstract: A radiotherapy apparatus comprises a means for producing a beam of radiation directed along a beam axis and having a width in first and second directions transverse to the beam axis, a multi-leaf collimator for selectively limiting the width of the beam in at least the first direction, a block collimator for selectively limiting the width of the beam in at least the second direction, the block collimator comprising a diaphragm moveable into and out of the beam and having a thickness in the direction of the beam axis that varies. The diaphragm can have a front edge of greater thickness than at least one region behind the front edge. It can also have a spine region extending from a rear part thereof towards the front edge that is greater thickness than at least one region displaced laterally with respect thereto. Together, these can cover the areas that will not be fully shadowed by a dynamically moving MLC.

Abstract: A radiotherapy apparatus comprises a means for producing a beam of radiation directed along a beam axis and having a width in first and second directions transverse to the beam axis, a multi-leaf collimator for selectively limiting the width of the beam in at least the first direction, a block collimator for selectively limiting the width of the beam in at least the second direction, the block collimator comprising a diaphragm moveable into and out of the beam and having a thickness in the direction of the beam axis that varies. The diaphragm can have a front edge of greater thickness than at least one region behind the front edge. It can also have a spine region extending from a rear part thereof towards the front edge that is greater thickness than at least one region displaced laterally with respect thereto. Together, these can cover the areas that will not be fully shadowed by a dynamically moving MLC.