Elekta Ab (publ)

Elekta, Inc.

Elekta Ab

Elekta Ab (fuel)

John Allen

Kevin J Brown

Terry Arthur Large

Terence Bates

Leonard Knowles Brundle

Duncan Neil Bourne

David Anthony Roberts

Adrian Maxwell Smith

Andrew Long

Martin Sell

David Roberts

Maria Giulia Thompson

Julian Byrne

Colin Winfield

Sjoerd Crijns

David Mills

Systems and methods are disclosed for detecting Cherenkov radiation produced during radiotherapy. A radiotherapy system comprises a patient receiving space for receiving a patient, a therapeutic radiation source, and a light detector configured to detect Cherenkov radiation subsequent to the emission of therapeutic radiation. Optionally, the system may make use of a optically transmissive dielectric to produce Cherenkov radiation.

Light detection apparatus and methods for a radiotherapy system

A wireless signal transmitter is provided for a radiotherapy device, said radiotherapy device being configured to provide radiation to a subject via a source of radiation, and further being configured to output a non-continuous beam of radiation, wherein said non-continuous beam of radiation has a first, time-related property associated therewith. The wireless signal transmitter is configured to wirelessly transmit a signal comprising data regarding the first, time-related property that is associated with the non-continuous beam of radiation, to a wireless signal receiver.

Signal transmitter for a radiotherapy device

A radiotherapy apparatus comprises a source for producing a beam of ionising radiation along an axis, the beam covering a maximum aperture of the source, a collimator for collimating the beam to produce a collimated beam covering a sub-part of the maximum aperture, a patient support positioned in the path of the beam, a rotatable gantry, on which the source is mounted, for rotating the source around the patient support thereby to deliver the beam from a range of directions, an imaging device located opposite the source and with the patient support between the source and the imaging device, and mounted on the gantry via a drive member allowing translational motion of the imaging device in at least one direction perpendicular to the axis, and a control unit adapted to control the drive member to move the imaging device within the maximum aperture and maintain coincidence between the imaging device and the sub-part of the maximum aperture. Accordingly, the EPID can be moved during the treatment in order to maintain the collimated field of the radiation beam within the bounds of the EPID. This ensures that the image is valid and prevents damage to the EPID as a result of exposure of more sensitive (or less shielded) parts to the beam.

Portal imaging during radiotherapy

A radiotherapy apparatus is disclosed, with a linear accelerator for producing a beam of electrons, a target aligned with the electron beam, the target being capable of producing photons when electrons are incident thereon, and a material which is capable of producing neutrons when photons of sufficient energy are incident thereon. A neutron detector capable of providing a signal to a controller of the linear accelerator is provided, the controller being capable of varying the energy of the electrons of the electron beam.

Radiotherapy calibration

Radiotherapy apparatus comprises a source of radiation mounted on a chassis, the chassis being rotatable about a rotation axis and the source being adapted to emit a beam of radiation along a beam axis that intersects with the rotation axis; a patient support, moveable along a translation axis; a set of magnetic coils located on either side of the beam, for establishing a magnetic field at the point of intersection, spaced from that point along a first direction; the translation axis, the rotation axis, and the first direction being substantially parallel; and further comprising a multi-leaf collimator fixed in its orientation with respect to the source of radiation, the multi-leaf collimator comprising a plurality of elongate leaves disposed with their longitudinal directions substantially aligned with the first direction and movable in that direction between a withdrawn position in which the leaf lies outside the beam.

Radiotherapy and imaging apparatus

Embodiments of the present invention provide markers, phantoms, and associated methods of calibration which are suitable for use in both magnetic resonance imaging and radiographic imaging systems. A marker includes a first marker component having a first hydrogen proton density and a first mass density; and a second marker component having a second hydrogen proton density different than the first hydrogen proton density, and a second mass density different than the first mass density. The first marker component and the second marker component are non-magnetic.

Markers, phantoms and associated methods for calibrating imaging systems

Radiotherapy apparatus comprises a source of radiation mounted on a chassis, that is rotatable about a rotation axis and the source being adapted to emit a beam of radiation along a beam axis; a patient support, moveable along a translation axis; a set of magnetic coils located on either side of the beam, for establishing a magnetic field along a first direction; the translation axis, the rotation axis, and the first direction being substantially parallel; and further comprising a multi-leaf collimator fixed in its orientation with respect to the source of radiation, the multi-leaf collimator comprising a plurality of elongate leaves disposed with their longitudinal directions substantially aligned with the first direction and movable in that direction between a withdrawn position in which the leaf lies outside the beam, an extended position in which the leaf projects across the beam.

A radiotherapy system comprises a patient support, moveable along a translation axis, an imaging apparatus, comprising a first magnetic coil and a second magnetic coil, the first and second magnetic coils having a common central axis parallel to the translation axis, and being displaced from one another along the central axis to form a gap therebetween, the imaging apparatus being configured to obtain an image of a patient on the patient support, a source of radiation mounted on a chassis, the chassis being rotatable about the central axis and the source being adapted to emit a beam of radiation through the gap along a beam axis that intersects with the central axis, a multi-leaf collimator comprising a plurality of elongate leaves movable between at least a withdrawn position in which the leaf lies outside the beam, and an extended position in which the leaf projects across the beam, and a radiation detector mounted to the chassis opposite the source, the radiation detector having a plurality of detector elements aligned with the elongate leaves when projected onto an isocentric plane.

The present invention provides a radiation detector which comprises a tube and detector elements distributed over the tube. Such an arrangement can be used to provide information on a radiation beam prior to interaction with a patient and after interaction with the patient. The detector is particularly compact and therefore suited to use with apparatus where space is restricted. By a particular arrangement of detectors and optical fibers, the detector can provide data at all angles of rotation.

Radiation detector and radiotherapy apparatus

The present invention provides a linear accelerator in which a rotatable conductive vane is employed to vary the electromagnetic coupling between adjacent accelerating cells. The vane is sealed off from the rest of the linear accelerator by an insulating partition, so the pressure around the vane can be higher than in the rest of the accelerator. This greatly simplifies the mechanisms which may be used to control the rotation of the vane, allowing a higher bakeout temperature in manufacture and a higher rate of rotation in use.

Linear accelerator

Flat panel images obtained during concurrent radiotherapy typically suffer from artefacts that relate to the pulses of MV energy. For a radiotherapeutic apparatus comprising a pulsed source of therapeutic radiation, a detector comprising control circuitry, an array of pixel elements, each having a signal output and an 'enable' input and being arranged to release a signal via the signal output upon being triggered by the enable input, and an interpreter arranged to receive the signal outputs of the pixel elements, the interpreter having a reset control, there are advantages in the control circuitry being adapted to reset the interpreter after a pulse of therapeutic radiation, prior to enabling at least one pixel of the array. Alternatively, the control circuitry can prompt a plurality of pulses by the pulsed source and then enable a plurality of pixels of the array. In effect, the therapeutic pulses are grouped into a short flurry of pulses. It is therefore preferred that the plurality of pixels comprises substantially all the pixels of the array.

Imaging systems for ionising radiation

An accelerator comprises a plurality of accelerating cells arranged to convey a beam, adjacent cells being linked by a coupling cell, the coupling cells being arranged to dictate the ratio of electric field in the respective adjacent accelerating cells, at least one coupling cell being switchable between a positive ratio and a negative ratio. Such an accelerator in effect inserts a phase change into the E field by imposing a negative ratio, meaning that the beam will meet a reversed electric field in subsequent cells and will in fact be decelerated. As a result, the beam can be developed and bunched in early cells while accelerating to and/or at relativistic energies, and then bled of energy in later cells to bring the beam energy down to (say) between 100 and 300 KeV. Energies of this magnitude are comparable to diagnostic X-rays, where much higher contrast of bony structures exists. Hence the accelerator can be used to take kilovoltage portal images.

A standing wave linear accelerator has a plurality of resonant cavities located along a particle beam axis. One or more pairs of resonant cavities are electromagnetically coupled via a coupling cavity. A rotationally asymmetric element within the coupling cavity is adapted to rotate about an axis that is substantially parallel to the axis of the coupling cavity. The coupling cavity is imperfectly symmetric about its axis due to a relative excess of material disposed within the cavity in the portion opposed to the apertures. Rotation of the polarization of a TE mode inside the cylindrical cavity provided a simple single mechanical control of coupling value, that has negligible effect on the phase shift across the device. A slight frequency dependence on the angle of rotation is correctable by a relative excess of material located opposite the apertures between the coupling cavity and the accelerating cavities.

This device allows the variation of the coupling between two points in an RF circuit in a very simple way while maintaining the RF phase relationship and varying the relative magnitude of the RF fields. The device is characterized by a simple mechanical control of coupling value, that has negligible effect on the phase shift across the device. This is achieved by the simple rotation of the polarisation of a TE mode inside a cylindrical cavity. Such a device does not contain resistive elements, and the sliding mechanical surfaces are free from high RF currents. This device finds an application in standing wave linear accelerators, where it is desirable to vary the relative RF field in one set of cavities with respect to another, in order that the accelerator can operate successfully over a wide range of energies.

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Haywards Heath, United Kingdom

John Allen