Elekta Ab

William R Harwood

Kevin J Brown

Terence Bates

Christopher John Snook

A patient support comprises two arms pivotally connected together and which extend between a base and a support to which a patient support table is coupled. In the preferred form, each arm comprises linkages which define pivot points A to D and A to D forming parallelograms. This ensures the support , and hence the table, has a constant orientation relative to the base. The arms may be controllable independently.

Patient support

A collimator for a therapeutic linear accelerator comprising first and second opposed arrays of individually longitudinally moveable elongate leaves, and a blocking element arranged transverse to the two arrays and moveable in that transverse direction, thereby to move into a gap between the tips of a leaf from the first array and a leaf from the second array. The blocking element and the two arrays can be in the same plane, thereby reducing the overall height of the device. As the tips of the leaves are usually profiled, it is preferred that the side edges of the blocking element are profiled to a complementary shape. The side edges of the leaves are usually non-vertical in order to allow for the divergence of the radiation beam. Each leaf will have a different angle. Accordingly, it is preferred that the tip of the blocking element has a variable angle, in order to match the angle of whichever leaf is adjacent. This could be achieved, for example, by making at least the tip in a laminar fashion so that each lamination can slide to form a tip which is angled. Alternatively, a rotatable element could be incorporated into the tip. It is also preferred that the blocking element has a flange which extends from a side thereof, positioned to extend adjacent over the tolerance gap between the blocking element and the leaf. It is obviously preferred if there are two blocking elements, disposed on opposite sides.

Multi-leaf collimator

A treatment source (4) such as a radiation source, is attached to the inner surface 50a of a drum 50, which drum 50 is mounted to a support (3) so as to be rotatable with respect to the support (3) about a central axis (R) displaced from the treatment source (4). The source provides a treatment beam (X) having a treatment beam axis (TB) extending through the rotation axis (R). A patient support (6) for receiving a patient (2) to locate a target treatment area (6) on the treatment beam axis (TB) is housed at least partially within the passageway defined by the inner surface 50a. The overall size of the apparatus is thus reduced. A preferred treatment technique, to which the apparatus may be adapted, is also described.

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West Sussex, United Kingdom

William R Harwood