Abstract: A treatment planning apparatus comprises a means for receiving a three dimensional representation of a patient, a means for displaying at least a part of the representation, a means for user-designation of sub-regions of the representation, and a computing means adapted to segment the representation into a region within an anatomical structure and a region outside the anatomical structure on the basis of the locations of the sub-regions and the degree of similarity of voxels to neighboring voxels in the representation. The treatment planning apparatus preferably further comprises means for designating sub-regions as being inside the structure, means for designating sub-regions as being outside the structure, and/or means for designating sub-regions as being at a border of the structure. In the latter case, we prefer that the size of border sub-regions is adjustable. The computing means can segment the representation by minimizing a cost function.

Abstract: A treatment planning apparatus comprises a means for receiving a three dimensional representation of a patient, a means for displaying at least a part of the representation, a means for user-designation of sub-regions of the representation, and a computing means adapted to segment the representation into a region within an anatomical structure and a region outside the anatomical structure on the basis of the locations of the sub-regions, the degree of similarity of voxels to neighboring voxels in the representation, and a dataset representing an a priori assumption of the correct segmentation. •The dataset preferably comprises a probability distribution of each pixel being within the segmentation, e.g. obtained from a segmentation of a previous image of the patient, for example by smoothing the previous segmentation. The at least part of the representation comprises one or more sections through the representation, such as axial, sagittal and/or coronal views of the patient.

Abstract: An apparatus has a patient support, a rotatable gantry supporting a source of imaging radiation, and a radiation detector that operates in a cyclical pattern of an exposure phase followed by a readout phase. For a first detector cycle in which the gantry has a first angle of rotation, the source of radiation is controlled to emit a first radiation beam pulse during the exposure phase, and respective first imaging data is read out during the readout phase. For a second, subsequent detector cycle, it is determined if the gantry has rotated through at least a threshold angular displacement relative to said first angle of rotation, and if so, the source of radiation is controlled to emit a second radiation beam pulse during the exposure phase, and respective second imaging data is read out during the readout phase.

Abstract: The present invention relates to an arrangement for supporting one or more cables, wires or hoses during repeated movements between a first and second end position. The arrangement comprises: a component support structure; a component turnable between the first and second end position; one or more elongated cables, wires or hoses; and a winding element. The one or more cables, wires or hoses are lead along the support structure to the winding element and continues to component and the surplus length of the cables, wires or hoses absorbed within the winding element. The invention furthermore relates to a medical device comprising said arrangement.

Abstract: This invention relates to a fixation device and a method for immobilizing a head of a patient relative a treatment unit or medical device during treatment of the head. The fixation device is provided with an interface unit adapted to be fixated in relation to an adaptor unit for connection to the treatment unit, or to a frame for connection to the medical device. Furthermore, the fixation device is provided with a bite-block for being inserted into a mouth of a patient and a positioning arrangement movably connecting the bite-block to the interface unit. The positioning arrangement is adapted to be fixated by means of an adhesive for fixation of the bite-block such that the head of a patient can be immobilized relative said adaptor unit or frame.

Abstract: 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.

Abstract: We provide a radiotherapy apparatus including a source of therapeutic radiation, a source of imaging radiation having an energy level less than that of the therapeutic radiation, a detector for radiation lying within the field of both the therapeutic radiation and the imaging radiation and able to image both, a first imaging circuit supplied with the output of the detector, a second imaging circuit also supplied with the output of the detector, a first pulse trigger circuit adapted to trigger the source of therapeutic radiation to produce a pulse of therapeutic radiation and to trigger the first imaging circuit to capture an output of the detector; and a second pulse trigger circuit adapted to trigger the source of imaging radiation to produce a pulse of imaging radiation and to trigger the second imaging circuit to capture an output of the detector.

Abstract: The co-registration error can be estimated by performing a number of additional iterative co-registrations, each iteration having a starting point dictated by the found co-registration transformation, and using a set of initial parameters different to that of the co-registration being tested. The spread in the resulting co-registrations can then be used as the estimate of the co-registration error. The variations in the set of initial parameters can include (i) the candidate transformation which the iteration uses as its starting point, adopting starting points that are offset from the co-registration being tested, (ii) the sample points used for the mutual information metric (or whichever metric is used to optimise the transformation), and (iii) the region-of-interest that is selected. Ideally, all three are varied to some extent within the plurality of additional co-registrations that are performed, and an average value is taken.

Abstract: The present invention provides a radiotherapy apparatus for applying therapeutic radiation to a target region of a patient, comprising a patient support, a source of radiation, a collimator comprising a plurality of leaves, a sensing system and control circuitry. The position of a target region is determined and resolved into two components orthogonal to the radiation beam axis. One component is assigned to the patient support, and the other to the collimator leaves, such that movement of the target region is compensated for and the radiation beam intersects is correctly targeted.

Abstract: Standby power supplies for patient tables need frequent replacement of the lead-acid batteries on which they depend. We propose to feed the emergency power direct to the drive motors, subsequent to the control circuitry. This will reduce the load on the standby power system, allowing greater design freedom to select longer-lasting or less expensive energy stores.

Abstract: Apparatus for location-detection of an object within a region comprising a reflective element mountable on the object, a scanning light source adapted to issue a beam of light in a scanning pattern illuminating a point that moves over the region, a detector for light reflected from the reflective element and a control unit adapted to report the position of an object based on the point in the scanning pattern at which the detector detects light returned from the reflective element relative to at least one point in the scanning pattern at which the detector detects light returned from a reflective object.

Abstract: The primary collimator for a radiotherapy apparatus can be made up of several layers, each comprising several apertures, and each layer being moveable so as to select a specific aperture to build up the primary collimator shape. In this way, the shape of the primary collimator can be tailored and/or the beam filters incorporated into the primary collimator assembly. This saves space in the radiation head whilst also allowing filters to be easily interchanged.

Abstract: A patient's lesion is localized for the purpose of administering radiation treatment by obtaining a beam shape representation along one or more beam directions of a radiation treatment device. An image corresponding to the lesion is obtained from each beam direction, and the beam shape and image are fixed to a common coordinate system to facilitate alignment.

Abstract: 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.

Abstract: The present invention introduces a method, apparatus and computer program for magnetic resonance imaging or magnetoencephalography applications in order to control currents of a coil assembly (20), and thus achieving desired magnetic fields precisely in the measuring volume (21). The approach is an algebraic method where a field vector is generated for the test currents of each coil (20). Vector and matrix algebra is applied and a linear set of equations is formed. Field components and their derivatives up to the desired order can be taken into account. Principal component analysis or independent component analysis can be applied for determination of the dominant external interference components. By checking the condition value for the matrix (33, 45), it is possible to investigate whether a reasonable solution of currents for desired magnetic fields is possible to achieve. Finally, solved currents can be installed into a current supply unit (29) feeding the coils of the assembly (20).

Abstract: Intra-fraction movement of the patient puts at risk sensitive regions that are near to a radiation dose. In a radiotherapy system that delivers a dose as a series of discrete sub-doses, an initial CT scan is performed to determine the patient's position, after which the sub-doses that are directed to regions within a preset distance of a sensitive structure are performed first, while the sub-doses directed to regions that are more remote from a sensitive structure are performed later.

Abstract: An apparatus and method of segmenting an image using scribble segmentation is provided, An image is segmented by constraining the membership value of a subset of image elements, solving a weighted biharmonic equation subject to the constrained membership values wherein the weights are determined from similarities between image elements, and determining the final segmentation based on the membership value of each image element.

Abstract: A method for planning a treatment session of a patient and optimizing the treatment time for a treatment using a radiation therapy system includes a radiation therapy unit having a fixed radiation focus point. During an optimization of a treatment plan for a patient, a set of shots to be delivered to a plurality of isocenter positions within a target volume of a patient during a treatment session are determined and a beam-on time for each respective sector and state for each isocenter during which radiation is to be delivered are determined based on the treatment plan. For each isocenter position, sectors and states of respective sector are grouped in accordance predetermined rules with respect to beam-on times for respective state of the sectors, wherein sectors and respective states are aggregated for simultaneous delivery of radiation during a predetermined period of time.

Abstract: A multi-leaf collimator for a radiotherapy apparatus comprises a plurality of elongate leaves mounted in a carriage, the carriage being mounted on a substrate, wherein the leaves are independently moveable relative to the carriage in a longitudinal direction, and the carriage is moveable in that direction relative to the substrate, and a control apparatus is arranged to receive a signal representing leaf positions relative to the substrate and to control the leaf positions relative to the carriage and the carriage positions relative to the substrate so as to achieve those leaf positions relative to the substrate. Most MLCs sense the current positions of the leaves relative to the substrate. The control apparatus can therefore compare the current leaf positions to the signaled leaf positions, and move the leaves and the carriage accordingly. A corresponding method is also disclosed.

Abstract: Methods of radiotherapy planning and delivery are disclosed in which a radiation beam is directed towards a time-averaged mean position of the target during radiation-on. In addition, the radiation beam is gated to deliver radiation to the target only when the target is within a treatment volume centered on the mean position. Treatment plans according to embodiments of the present invention result in low doses to the surrounding healthy tissue, but high duty cycles and quicker treatment times.