Elekta Ab (publ)

Elekta, Inc.

Elekta Ag (publ)

Elekta Ab

Paul Boxall

Kevin J Brown

Duncan Neil Bourne

Ralph Streamer

Adrian Maxwell Smith

Paul Berwick

David Burt

Christopher James Gibson

Ralf Spriesterbach

Neil Pritchard

Marco Massai

Kevin Brown

A method of determining whether a radiotherapy device configured to provide therapeutic radiation to a patient should be authorised for use. The device comprises a plurality of components, each component of the plurality of components being coupled with at least one identifier configured to provide data identifying the component it is coupled with. The method comprises receiving, from the identifiers, data identifying each of the plurality of components of the radiotherapy device and determining whether at least one authorisation criterion is met based on the identifying data and authorisation data; and if the at least one authorisation criterion is met, determining that the radiotherapy device is authorised for use.

Radiotherapy devices and access authorisation

A radiotherapy system, comprising: a patient support, a radiation beam generator, a gantry on which the radiation beam generator is mounted, the gantry being moveable so as to rotate the radiation beam generator around the patient support, and a control system including a real-time control system mounted on the gantry and configured to provide real-time control signals to the patient support, the radiation beam generator, and the gantry.

Radiotherapy control system

A method for dealing with the effects of inertia in a radiotherapy apparatus is disclosed. The method may include catering for inertia in advance by incorporating inertia factors into an output from a delivery control system which adapts the treatment plan by incorporating the inertia factors, or by including the inertia factors as a constraint in the treatment planning process. The instructions delivered to the geometry items may reflect their inertia behavior and can therefore be followed very closely. This may indicate that a departure from that plan will be correspondingly more likely to indicate an error by the geometry item. When a geometry item needs to accelerate or decelerate, less error may arise and thus the error-checking regime may not necessarily make allowances for such departures from the intended path, thereby tightening the error tolerances. Error-checking may be safely carried out locally for each component.

Radiotherapy apparatus using inertial characteristics for delivery planning

Apparatus comprising a radiation source which can rotate in an arc around the radiation beam axis, a multi-leaf collimator (MLC), and a controller for the source dose/time rate, the source rotation speed, and the MLC position. The controller calculates the time required for (i) an MLC leaf movement from start to end of an arc-segment at a maximum leaf speed, (ii) rotation of the source from start to end of the arc-segment at a maximum speed, and (iii) delivery of the dose at a maximum dose rate per time, selects the longest of (i), (ii) and (iii), and operates the selected one at its maximum and the others at a reduced rate matching that longest time, the time required for (i) and/or (ii) being the greater of the time to complete the segment at a continuous speed and the time to accelerate the item to that speed.

Radiotherapeutic apparatus

A radiotherapeutic apparatus comprises a source able to emit a beam of therapeutic radiation along a beam axis, a multi-leaf collimator arranged to collimate the beam to a desired shape, wherein the source is rotatable about a rotation axis that is substantially orthogonal and intersects with the beam axis thereby to describe an arc around that axis, and further comprises a control means able to control the dose/time rate of the source, the rotation speed of the source, and the multi-leaf collimator position. The control means is arranged to control the source in accordance with a treatment plan over first and second arc-segments such that at least the multi-leaf collimator changes shape at a different rate per degree in the second arc-segment as to the first arc-segment.

Recent advances in treatment planning and in the apparatus able to deliver such plans has called for the dose rate, i.e. the instantaneous power output of the radiation source, to be varied with time. This presents a difficulty in that the checking systems must monitor a varying power level against a varying valid range. We therefore monitor, instead, the energy of the individual pulses that form the beam. Known checking systems average out many pulses to determine the recent average power output by checking an ionization chamber every 100 ms or so. By reducing that time to less than a few milliseconds, a single pulse can be captured. The usual manner of varying the output of a radiation source of this type is to vary the pulse repetition frequency (PRF) and therefore the measured power output will remain constant notwithstanding changes to the time-averaged power output, and can be compared to a standard.

Radiotherapy apparatus

The detected positioning error in a geometry item of a radiotherapy apparatus is generally passed to a transfer function for the system, which outputs a signal that dictates the radiation output. If the detected error is within certain limits then the radiation is permitted whereas outside those limits it is not permitted; this corresponds to a transfer function that is a simple two step function. We propose a transfer function having a result that is (a) substantially zero outside a preset error tolerance, (b) has a maximum result at a point within that tolerance, and (c) has a result that is between zero and that maximum over a range of error values that lie between (i) the error value corresponding to the maximum output and (ii) the preset error tolerance. This means that if an error grows towards (but does not exceed) the error tolerance, the output of the radiation source will reduce and allow time for the geometry item to correct its position.

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Crawley, United Kingdom

Paul Boxall