| ELEKTA AB (PUBL) Patent applications |
| Patent application number | Title | Published |
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| 20120076269 | Radiotherapy Apparatus - 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. | 03-29-2012 |
| 20110319741 | Adapting radiotherapy treatment plans - Embodiments of the present invention provide a method of pre-approving a range of hypothetical spatial variations of the target whilst an initial treatment plan is generated. This allows the treatment plan to be later adapted to account for spatial variations of the target region falling within those pre-approved ranges, without going through time-consuming steps of quality assurance on the adapted plan. | 12-29-2011 |
| 20110272568 | CALIBRATION METHOD - The invention relates to a method for calibrating a measurement tool for measuring the radiation in a radiation system, such as a radiation therapy system. The measurement tool, including a holder and at least one photodiode element, is adapted to be mounted in a positioning unit of the radiation system. The radiation sensitive volume of the photodiode element is embedded in a light transparent coating transparent for, for instance, light in the visible spectrum. Thereby, the position of the sensitive volume can easily be determined or calculated with high accuracy relatively the holder on which the photodiode element is arranged, from which the position of the sensitive volume can be determined or calculated in relation to the positioning unit of the radiation system. The invention also relates to a calibration system for performing the calibration method and a measurement tool for use in the calibration system. | 11-10-2011 |
| 20110255665 | Planning for adaptive radiotherapy - The present invention provides a method for updating and optimizing a treatment plan for radiotherapy. An initial treatment plan, calculated using a constraint-driven method, may be updated using a weighted-sum method, where Lagrange multipliers generated in the constraint method are reused as the weights for the weighted sum. This method results in acceptable updated treatment plans that are generated in a small fraction of the time taken to generate an entirely new treatment plan, reducing patient discomfort and ensuring the radiotherapy facility can treat more patients. | 10-20-2011 |
| 20110243387 | Analysis of Radiographic Images - The present invention therefore provides a method for the analysis of radiographic images, comprising the steps of acquiring a plurality of projection images of a patient, acquiring a surrogate signal indicative of the location of a target structure in the patient, reconstructing a plurality of volumetric images of the patient from the projection images, each volumetric image being reconstructed from projection images having a like breathing phase, identifying the position of the target structure such as a tumour in each volumetric image, associating a surrogate signal with each of the projection images, and determining a relationship between the surrogate signal and the position of the target structure. Multiple projection images having a like breathing phase can be grouped for reconstruction, to provide sufficient numbers for reconstruction. The analysis of the multiple values of the surrogate associated with each breathing phase can be used to determine the mean surrogate value and its variation. Multiple values of the surrogate signal associated with the same nominal breathing phase can be used to determine a mean value of the surrogate signal for the target position associated with that phase and a variation of the value of the surrogate signal for the target position associated with that phase. The breathing phase of specific projection images can be obtained by analysis of one or more features in the images, such as the method we described in U.S. Pat. No. (7,356,112), or otherwise. | 10-06-2011 |
| 20110206252 | Radiotherapeutic Treatment Planning Apparatus and Methods - 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 neighbouring 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 minimising a cost function. We also prefer that the initial values of the function in sub-regions designated as being in a border region are constrained to a different preset value. In an particularly useful aspect of this invention, after minimisation of the function the values in sub-regions designated as being in a border region are then un-constrained, the remaining values are constrained, and the function is then minimised a second time. | 08-25-2011 |
| 20110201920 | Radiotherapy and imaging apparatus - 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. | 08-18-2011 |
| 20110201919 | Radiotherapy and imaging apparatus - 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, an extended position in which the leaf projects across the beam and a plurality of intermediate positions therebetween. | 08-18-2011 |
| 20110201918 | Radiotherapy and imaging apparatus - 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 and 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, the beam having a first extent in a first direction parallel to the central axis, and a second, greater extent in a second direction transverse to the central axis. | 08-18-2011 |
| 20110199085 | Radiotherapy and imaging apparatus - 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. | 08-18-2011 |
| 20110160727 | RIGID SKULL FIXATION - The invention relates to a stabilizing device adapted to be applied to a stereotactic frame ( | 06-30-2011 |
| 20110142202 | Radiotherapy Apparatus - It is desirable to achieve a co-incident investigative kV source for a therapeutic MV source—a so-called “beams-eye-view” source. It has been suggested that bremsstrahlung radiation from an electron window be employed; we propose a practical structure for achieving this which can switch easily between a therapeutic beam and a beam-eye-view diagnostic beam capable of offering good image resolution. Such a radiation source comprises an electron gun, a pair of targets locatable in the path of a beam produced by the electron gun, one target of the pair being of a material with a lower atomic number than the other, and an electron absorber insertable into and withdrawable from the path of the beam. In a preferred form, the electron gun is within a vacuum chamber, and the pair of targets are located at a boundary of the vacuum chamber. The lower atomic number target can be Nickel and the higher atomic number target Copper and/or Tungsten. The electron absorber can be Carbon, and can be located within the primary collimator, or within one of a plurality of primary collimators interchangeably locatable in the path of the beam. Such a radiation source can be included within a radiotherapy apparatus, to which the present invention further relates. A flat panel imaging device for this source can be optimised for low energy x-rays rather than high energy; Caesium Iodide-based panels are therefore suitable. | 06-16-2011 |
| 20110121763 | Linear Accelerators - We propose that during the factory testing of the linac, rather than simply confirming that the beam falls within the permissible ranges set out in the standard, the beam is in fact adjusted towards a standard signature. A new (or existing) linac could then be paired to a new linac, or to an existing linac, such as one that it is to operate alongside or one that it is to replace. Treatment plans would then be transferable between such pairs of linacs. In addition, the standard signature to which the linacs were approximated could be placed towards the centre of the permitted ranges, to produce linacs that were more reliable over the very long term. This requires a linac that has automatically adjustable parameters, so that a suitable programmed computer is able to monitor the output of the linac and adjust its operating parameters. We therefore provide a radiation source comprising a linear accelerator, beam control circuitry for the linear accelerator, an electronic control apparatus for the control circuitry arranged to adjust properties thereof, and a monitor for detecting properties of the radiation beam produced by the linear accelerator, wherein the control apparatus is adapted to retain a set of beam properties and periodically activate the accelerator, measure the current beam properties via the monitor, compare the measured beam properties to the retained beam properties, and potentially adjust the control circuitry properties to align the beam properties towards the retained beam properties. The beam properties that are measured may include at least one of beam flatness and beam width. The retained beam properties can be the properties of the beam produced by the linear accelerator when new, or the properties of a standard beam. The control apparatus is preferably arranged to send a message if the difference between the measured beam properties and the retained beam properties exceeds a threshold. It may also send a message to a remote location if the difference between the measured beam properties and the retained beam properties exceeds a second threshold. | 05-26-2011 |
| 20110049396 | Multi-Leaf Collimators - 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 arranged to receive a signal representing leaf positions relative to the substrate and being arranged 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. By allowing the carriage to be driven concurrently with the leaves, the speed of movement of the carriage can be added to that of the leaves. In this way, where leaves are required to make a long traverse they can do so more quickly. Most MLCs have a means for sensing the current positions of the leaves relative to the substrate, such as an optical or mechanical positional feedback system. The control apparatus can therefore compare the current leaf positions to the signalled leaf positions, and move the leaves and the carriage accordingly. Each leaf can be moved according to a difference between the current leaf position and the signalled leaf position, and the carriage can be moved according to an average difference between the current leaf positions and the signalled leaf positions. A corresponding method is also disclosed. | 03-03-2011 |
| 20110026683 | Multi-leaf collimators - A multi-leaf collimator for a radiotherapy apparatus comprises at least one array of laterally-spaced elongate leaves, each leaf being driven by an associated motor connected to the leaf via a drive means so as to extend or retract the leaf in its longitudinal direction, the drive means comprising a sub-frame on which at least a subset of the motors are mounted, the sub-frame being mounted at a location spaced from the leaf array in a direction transverse to the lateral and longitudinal directions, and including a plurality of threaded drives disposed longitudinally, each being driven by a motor and being operatively connected to a leaf thereby to drive that leaf. | 02-03-2011 |
| 20110013818 | 3D Medical Image Segmentation - 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 neighbouring 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. The computing means can segment the representation by minimising a function. | 01-20-2011 |
| 20100329422 | 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 rotateable 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 receive a treatment plan in which the arc is divided into a plurality of notional arc-segments, and specifying the total dose for the arc-segment and a Start and end MLC position. It then controls the source in accordance with that plan over an first arc-segment such that at least one of the rotation speed and dose rate are constant and the multi-leaf collimator changes shape, and a second arc segment such that at least one of the rotation speed and dose rate are constant at a level different to the constant level adopted during the first arc-segment. It achieves this by calculating the total time required for the arc segment for a plurality of factors including an MLC leaf movement from a prescribed position at the start of the arc-segment to a prescribed position at the end of the arc-segment, at a maximum leaf speed, rotation of the source from the start to the end of the arc-segment at a maximum source rotation speed, delivery of the dose at a maximum dose rate per time, selecting the factor dictating the longest time, and Controlling the apparatus so that the selected factor operates at its respective maximum and the remaining factors are operated at a reduced rate selected to match that longest time, wherein the total time required for the arc segment for at least one factor relating to a moving geometry item is the greater of (a); a time required to complete the segment at a continuous defined upper speed for the geometry item and (b) a time required to accelerate the geometry item until it is travelling at the defined upper speed. Generally, the time required to accelerate the geometry item to the defined upper speed will include a time to accelerate the geometry item to that speed, and a further time to accelerate the geometry item beyond that speed and subsequently decelerate it until travelling at that speed. | 12-30-2010 |
| 20100322491 | Calibration of volume acquired images - A method is disclosed whereby a prior reference image is used as a calibration source for a volume image prepared using less accurate apparatus, such as during therapy. Thus, a volume image of a patient is prepared by acquiring a reference image of the patient suitable for treatment planning purposes, acquiring a subsequent image of the patient, selecting a plurality of voxels in one of the subsequent image and the reference image, and preparing a histogram of the voxel values in a region around each selected voxel, to form a first set of histograms, identifying the corresponding regions in the other image and preparing a histogram of the voxel values in each of those corresponding regions, to form a second set of histograms, for each histogram in the first set, identifying a transformation that transforms it to be substantially the same as the corresponding histogram of the second set,; thereby to derive a set of transformations, and applying a transformation to voxels in the subsequent image based on the set of transformations. | 12-23-2010 |
| 20100310045 | X-ray Apparatus - X-ray apparatus comprises a linear accelerator adapted to produce a beam of electrons at one of at least two selectable energies and being controlled to change the selected energy on a periodic basis, and a target to which the beam is directed thereby to produce a beam of x-radiation, the target being non-homogenous and being driven to move periodically in synchrony with the change of the selected energy. In this way, the target can move so that a different part is exposed to the electron beam when different pulses arrive. This enables the appropriate target material to be employed depending on the selected energy. The easiest form of periodic movement for the target is likely to be a rotational movement. The target can be immersed in a coolant fluid such as water. The linear accelerator can be of the type disclosed in WO2006/097697A1. The target preferably contains at least one exposed area of tungsten and/or at least one exposed area of carbon. These can be present as inhomogeneities in the material of which the target is composed, such as Carbon inserts in a Tungsten substrate (or vice versa), alternating segments of Carbon and Tungsten, Carbon and Tungsten inserts in a substrate of a third material, or arrangements involving other materials in addition to or instead of Carbon and/or Tungsten. Alternatively, the target can be of a homogenous material but have inhomogeneities in its thickness to cater for the different electron energies. The same concept can be applied to the filter. A detector can be provided, operating in synchrony with the energy variation. Such an x-ray apparatus can form a part of a radiotherapy apparatus, in which case the first selected energy can be a diagnostic energy and a second selected energy a therapeutic energy. | 12-09-2010 |
| 20100278306 | Apparatus for Respiration State Gated Brachytherapy - During treatment by brachytherapy, radiation passes beyond the target volume and delivers radiation dose to adjacent tissue such as the lungs and, especially in the case of treatment of the left breast, to the heart. The heart is particularly vulnerable to radiation; to minimise the dose it receives in such circumstances, we propose an apparatus for treatment by brachytherapy comprising an X-ray source sized for insertion into a patient, a respiration state monitor, and a control apparatus adapted to receive respiration state information from the respiration state monitor and control the output of the X-ray source; the control apparatus being arranged to operate the X-ray source at a first output level when the respiration state monitor indicates a degree of lung inflation above a first preset threshold and operate the X-ray source at a second and lower output level when the respiration state monitor indicates a degree of lung inflation below a second preset threshold. | 11-04-2010 |
| 20100275926 | FIXATION DEVICE - The present invention relates to the field of radiation therapy and radiation surgery. In particular, the invention relates to devices and methods for stereotactic medical procedures and it provides for repeated accurate positioning (fixation) of a patient, or a part of a patient, for carrying out medical procedures which are done at different times such as fractionated radiation therapy. Specifically, a patient fixation device for fixating a head of a patient relatively a treatment unit as a preparation for treatment or during treatment of the head is provided. The patient fixation device being is adapted to be attached to a stereotactic frame structure connected to the treatment unit. The attachment means is adapted to be releasably attached to corresponding attachment plates attached to teeth of the upper jaw or maxilla of the patient, each attachment plate being fixated to at least one tooth by means of an adhesive, wherein the attachment means allows removal from the attachment plates of the patient and re-attachment to the corresponding attachment plates of the patient with an identical orientation relatively the frame structure and the teeth of the patient. | 11-04-2010 |
| 20100268308 | CRANIUM PLUG - The present invention relates to a device for securing medical leads in a cranial burr hole, in particular, for securing a brain stimulation lead within such a burr hole. The device includes a circular socket element adapted to be secured within a burr hole of the skull of a patient, the circular socket element having a through lead passage arranged to have the lead pass therethrough, the lead passage including passage walls including at least one resilient partition wall extending from an inner wall of the circular socket element, and the circular socket element having at least one inner compartment delimited by the partition wall. Further, the device includes a cap element having a circular upper portion being arranged to mate with the socket element, the circular upper portion having at least one protruding member arranged to co-operate with the at least one inner compartment when placed into the compartment so as to apply a radial pressure on the at least one resilient partition wall such that a lead passing through the passage is fixated in the passage by a resulting radial pressing force. | 10-21-2010 |
| 20100252754 | Radiotherapy Apparatus - Realtime beam shape adjustment in response to (for example) online CT scanning of a patient during treatment is assisted by the radiotherapy apparatus comprising a source adapted to emit a beam of therapeutic radiation, a collimator for delimiting the radiation beam, the collimator comprising a plurality of leaves arranged alongside each other and be moveable longitudinally so that the tips of the leaves define a variable edge of the collimator, the leaves being mounted on a support that is moveable laterally with respect to the leaves. In this way, movements of the tumour that are perpendicular to the direction of leaf motion can be accommodated by simply moving the collimator bodily so as to accommodate this. It is preferred that the apparatus also includes a control means adapted to receive information as to the location of the target volume, and, on the basis of that information, control the longitudinal positions of the leaves and the lateral position of the support. It is also preferred that the support tilts as it moves laterally along a path. This can be achieved, by example, by bearings that are moveable on suitable guides, or by mounting the support on a plurality of pivot arms of unequal lengths. The lengths of such pivot arms can be adjusted as necessary. | 10-07-2010 |
| 20100166286 | Motion artefact reduction in CT scanning - An example of sporadic motion that causes difficulty in CT scanning is gas pockets moving around the rectum. The invention allows the automatic detection of such movements, by enhancing low density features around the prostate in the individual X-ray images, projecting these features on the cranio-caudal axis (assuming that the gas predominantly moves in this direction) to form a 1-dimensional image, and combining successive ID projections to form a 2D image. Moving gas will produce tilted lines in this image, identifying an angular range that needs to be discarded. Such a process can be used in an image processing apparatus of a CT scanner. | 07-01-2010 |
| 20100166150 | Collimation apparatus for radiotherapy - 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. A control means for the multi-leaf collimator can be arranged to extend leaves of the multi-leaf collimator to shadow regions of the beam that are blocked by a relatively thinner section of the diaphragm. This is made easier if the spine region extends from the rearmost part of the diaphragm, the spine region extends to the front edge of the diaphragm, the spine region is straight, the spine region is a central region of the diaphragm, and if the width of the spine region increases towards the front edge of the diaphragm. The present invention also relates to a radiotherapy apparatus comprising a multi-leaf collimator and a block collimator, the block collimator comprising a diaphragm with variable thickness, and to a block collimator for use in radiotherapy apparatus comprising a diaphragm moveable into and out of a beam, and having a thickness in the direction of the beam axis that varies. | 07-01-2010 |
| 20100128951 | Radiotherapeutic Apparatus and Methods - A treatment planning apparatus for radiation treatment is described, adapted to accept a treatment plan comprising (i) a prior image of a region to be treated and a plurality of dose locations within the prior image, and (ii) a current image of the region to be treated, the apparatus comprising an associating means arranged, for each dose location, to locate an anatomical structure in the prior image proximate that dose location; a comparator for comparing the prior image and the current image, locating in the current image at least those anatomical structures that are associated with a dose location, and determining a transformation between the prior image and the current image for each anatomical structure; and a processing means for determining a current dose location by applying to each dose location the transformation determined in respect of the associated anatomical structure. This is particularly useful for the neck region of a patient, where the likelihood and magnitude of movements are both high, but there are plenty of distinguishable anatomical features in the form of the vertebrae. | 05-27-2010 |
| 20100104070 | Radiographic apparatus - For Respiration Correlated Cone Beam CT scanning, we have observed that improvements in the frame rate are in fact undesirable. We therefore propose a radiographic apparatus comprising a beam of radiation and a detector therefor, adapted to obtain a two dimensional image of the beam after passing through a cyclically varying object to be investigated, a processor adapted to review the images and select images at like points in the cycle, and a control means for the beam of radiation adapted to activate the beam periodically. The control means can activate the beam at a frequency of between 0.5 and 5 Hertz, more preferably between 1 and 3 Hertz, which corresponds (roughly) to a frequency that is between 6 and 10 times the frequency of the cyclical variation. It will assist if the selected point of the cycle is an extremity thereof, as the rate of change in these areas is at a minimum. Thus, slight mismatches between the two cycles will then have only a small effect. Typically, the object will be a patient and the cyclical variation will be the patient's breathing cycle. | 04-29-2010 |
| 20100094153 | Respiration monitoring - A respiration sensor comprises a frame that is adapted to extend from a first point of contact on one side of a patient to a second point of contact on an opposing side of the patient, including a force sensor in the first point of contact. The second point of contact can comprise a patient support, which will usually support the patient in a generally horizontal state. The frame is preferably as shown in U.S. Pat. No. 5,681,326 with an arch extending over an area adapted to receive a patient. The first point of contact can include a plate which abuts the patient. The sensor is ideally located between the plate and the remainder of the frame. | 04-15-2010 |
| 20100057061 | Radiotherapeutic apparatus - A radiotherapeutic apparatus comprises a source of therapeutic radiation, a source of visible light arranged to cast a light field corresponding to the beam of radiation, and a multileaf collimator for shaping the beams, wherein a filter is disposed in the path of the visible light beam having a plurality of linear dark sections corresponding to leaves of the collimator. This prevents the incident light from falling on the leaves and removes the ghost images at source. By placing the filter in the head, the line can be very narrow and will be blurred into penumbra at the isocentre. This is therefore a very inexpensive yet effective method of reducing ghosting. A mirror can deflect the path of the visible light to correspond to that of the radiation beam, and the filter can be disposed anywhere in the beam path, such as prior to the mirror, subsequent to the mirror and prior to the collimator, or subsequent to the collimator. The filter thus creates dark sections in the light field corresponding to leaves (preferably all the leaves) of the collimator. | 03-04-2010 |
| 20100027763 | METHOD OF CALIBRATING A RADIATION THERAPY SYSTEM - The present invention concerns a method, a system, a measurement tool and computer readable medium for determining a predetermined position of a positioning system in a radiation therapy system comprising a radiation therapy unit relatively a fixed radiation focus point of the radiation therapy unit. The method comprises positioning ( | 02-04-2010 |
| 20090306483 | treatment planning systems - A treatment planning method comprises the steps of identifying a plurality of treatment locations and an overall dose to be applied to each, for each specific location identifying the global dose applied at that location by doses aimed at different locations, as a proportion of the dose applied at the respective different location, constructing a dose factor matrix containing for each location, the global doses arising from the dose applied at each other location, inverting the dose factor matrix and multiplying it with a prescription matrix containing the overall doses to be applied to each location, thereby to obtain a resultant matrix containing a local dose for each location. This provides a mathematically straightforward method of deriving the necessary doses to be applied to each target so that, including the global doses delivered while irradiating a different target, each target receives the correct total dose. Some locations can be omitted from the treatment planning method, for example if they are located so far from the other locations that they will not have a significant interaction with them. A corresponding treatment planning apparatus is also described. | 12-10-2009 |
| 20090293883 | Connecting device for connecting a rings-shaped frame to a supplementary equipment - A device is provided for connecting of a ring-shaped frame, which is adapted for fixation to the head of a patient during neurological diagnosis, therapy or surgery, to a supplementary equipment, for positioning of the frame and the equipment in a predetermined relation to each other. The frame comprises a connecting hole and the equipment comprises a connecting pin for insertion into the hole in the frame during positioning. The hole opens into a surface of the frame and has an enlarged portion, which preferably is diverging towards the surface of the frame, closest to the surface and a cylindrical portion beyond the diverging portion, whereas the connecting pin has a cross sectional dimension which is equal to or slightly smaller than the cross sectional dimension of the cylindrical portion in the hole. | 12-03-2009 |
| 20090270769 | SYSTEM FOR MEASUREMENT OF HEAD POSITION AND MEASUREMENT TOOL FOR SUCH A SYSTEM - The present invention relates to the field of radiation therapy. In particular, the relates to a system for measuring the position of a head of a patient during neurological diagnosis, therapy or surgery, in particular during radiation therapy relatively a frame adapted to be fixated to a radiation therapy unit. The invention also relates to a head cap and a measurement tool for use in such a system, and to a method measuring the position of a head of a patient by means of a system mentioned above during neurological diagnosis, therapy or surgery, in particular during radiation therapy relatively a frame adapted to be fixated to a radiation therapy unit. The measurement tool is adapted to measure a distance between the head and the head cap via a through hole by means of an elongated element having an end being adapted to abut against the head during a measurement, wherein the measurement tool is adapted to obtain at least one measurement value indicating a position of the head in relation to the head cap substantially without operator interaction | 10-29-2009 |
| 20090262901 | Multi-leaf collimators - A multi-leaf collimator for a radiotherapy apparatus comprises at least one array of laterally-spaced elongate leaves, each leaf being driven by an associated motor connected to the leaf via a drive means so as to extend or retract the leaf in its longitudinal direction, the drive means comprising a sub-frame on which at least a subset of the motors are mounted, the sub-frame being mounted at a location spaced from the leaf array in a direction transverse to the lateral and longitudinal directions, and including a plurality of leadscrews disposed longitudinally, each being driven by a motor and being operatively connected to a leaf thereby to drive that leaf. | 10-22-2009 |
| 20090238338 | RADIOTHERAPEUTIC APPARATUS - A reference phantom includes CT-imageable detail together with light-reflective spheres. This item can be placed on a patient table in a known location, following which the diagnostic source can be activated to detect the phantom position relative to the isocentre and camera employed to detect the PSS position. A synthetic image of the phantom can be used for comparison with the CT dataset. This allows improved correlation of the source and the patient support, enable further steps to be taken in enhancing the clinical effectiveness of the apparatus. In-use variations of the isocentre location can be corrected in real time by adjustment of the patient support. Thus, as the isocentre moves, the patient can be moved so as to track the moving isocentre. The linac arm could also be designed differently, as the existing design constraint (that isocentre movement must be limited as far as possible) could potentially be relaxed in order to achieve other aims. | 09-24-2009 |
| 20090213991 | 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 rotateable 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 receive a treatment plan in which the arc is divided into a plurality of notional arc-segments, and specifying the total dose for the arc-segment and a start and end MLC position. It then controls the source in accordance with that plan over an first arc-segment such that at least one of the rotation speed and dose rate are constant and the multi-leaf collimator changes shape, and a second arc segment such that at least one of the rotation speed and dose rate are constant at a level different to the constant level adopted during the first arc-segment. It achieves this by calculating the total time required for the arc segment for a plurality of factors including an MLC leaf movement from a prescribed position at the start of the arc-segment to a prescribed position at the end of the arc-segment, at a maximum leaf speed, rotation of the source from the start to the end of the arc-segment at a maximum source rotation speed, delivery of the dose at a maximum dose rate per time, selecting the factor dictating the longest time, and controlling the apparatus so that the selected factor operates at its respective maximum and the remaining factors are operated at a reduced rate selected to match that longest time. | 08-27-2009 |
| 20090207975 | Multi-leaf collimator - A multi-leaf collimator for use in a radiotherapeutic apparatus comprises a plurality of elongate narrow leaves arranged side-by side and supported in a frame, the frame having upper and lower formations for guiding each leaf into which extend ridges on the upper and lower edges of the leaves, thereby to allow the leaves to move in a longitudinal direction, the upper and lower formations being aligned so that the sides of the leaves when fitted are at a non-zero angle to the beam direction, the upper and lower ridges being located on the upper and lower edges of the leaves so that a line joining their centres is at a non-zero angle to the sides of the leaf, tilted relative to the sides in a sense opposite to that of the beam. An outer face of the upper and/or lower ridges can be aligned with a side face of the leaf, for ease of manufacture. A radiotherapeutic apparatus is also disclosed, comprising a source of radiation and a multi-leaf collimator for shaping the radiation emitted by the source, the multi-leaf collimator being as set out above. | 08-20-2009 |
| 20090196401 | Machine vision system - A fluorescing marker is used in order to mark (for example) a leaf of a multi-leaf collimator and/or the reference points within the field of view. The markers are illuminated with light tuned to cause the markers to fluoresce at a wavelength different to that of the illuminating light. The fluorescence is then detected by a camera. This method allows the image to be captured by the camera with increased contrast. Accordingly, the present invention provides a multi-leaf collimator for a radiotherapeutic apparatus, comprising at least one leaf having a fluorescent marker. The fluorescent marker will usually emit light of a wavelength longer than the incident light, allowing suitable filters to be provided in order to distinguish the light emitted by the markers. A suitable material for use in the fluorescent markers is ruby. The present invention also provides a radiotherapeutic apparatus comprising a multi-leaf collimator as defined above, and a camera arranged to view the fluorescent markers. A source of illumination for the fluorescent markers is ideally monochromatic, or nearly so. The camera can have a filter arranged to substantially prevent light of the wavelength emitted by the source of illumination from entering the camera, thereby improving the contrast of the image. The radiotherapeutic apparatus can also comprise a source of illumination that is optically co-located with a radiation source, to allow the radiation field that will be emitted to be checked visually by an operator. The co-located source is preferably substantially monochromatic, emitting substantially no light at the wavelength of the fluorescent markers. A filter can then be placed over an output of the radiotherapeutic apparatus, for blocking light of the wavelength of the fluorescent markers and thereby enhancing the contrast of the image that is taken of the fluorescent markers. | 08-06-2009 |
| 20090184709 | Method for Interference Suppression in a Measuring Device - The present invention describes a method enabling one to shield a device that measures weak biomagnetic signals from strong magnetic interference fields. The measurement sensors are provided with a feedback compensation loop, the difference signal of which is obtained from the measurement sensors themselves. As the actuator of the feedback function, one or more coils are responsible for eliminating, the external interference fields in the region of the sensors. Difference signals can be generated as a linear combination from the signals of two or more sensors. In the control logic, the SSS method can be used to numerically separate the biomagnetic signal being measured from the signals produced by the sources—compensation coils and interference sources—disposed outside the measurement region. The interference suppression can be enhanced by placing the assembly of sensors and the actuators within a magnetically shielding room. | 07-23-2009 |
| 20090173637 | Manufacture of Multi-Leaf Collimators - We propose to shape the leaf by the use of electro-chemical machining (ECM). ECM is a technique by which a blank is suspended within a mould, with a small gap therebetween. A conductive fluid is caused to flow through the gap, and a large electrical current is passed from the mould to the blank. The blank steadily erodes, dissolving into the fluid. The fluid should not provoke a reaction from the material of the blank, such as a surface oxide. Sodium Chloride solution is a common choice. The current that is passed can, if desired, be controlled to a profile that will affect the manner of erosion. Thus, the current profile can be a steady on/off current, or it can be pulsed. One known arrangement is for the current to rise to a peak, then fall to zero, followed by a brief reverse flow. | 07-09-2009 |
| 20090121155 | RADIOTHERAPY APPARATUS AND PARTS THEREOF - A geometry item (such as a gantry arm or an MLC leaf) of a radiotherapeutic apparatus needs to be moved in an accurate manner. The effect of inertia introduces a potential inaccuracy. A radiotherapeutic apparatus is therefore disclosed, comprising a geometry item, a radiation source capable of emitting a beam of therapeutic radiation, and a control unit, the geometry item being moveable to adjust the geometry of the beam, the radiation source having a variable dose rate, and the control unit being arranged to cause variations in the speed of movement of the geometry item and to adjust the dose rate of the radiation source for a period of time after a change in the speed of the geometry item. | 05-14-2009 |
| 20090110150 | RADIOTHERAPY APPARATUS AND PARTS THEREOF - 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. | 04-30-2009 |
| 20090097614 | Radiotherapy Apparatus and parts thereof - A mount for a radiotherapy apparatus comprises a cylindrical bearing surface to allow the mount to be supported in a rotatable manner, a housing extending from the bearing surface and having an extent in a direction along an axis of the cylindrical bearing surface, the mount having an axial through-hole which encompasses the axis of the cylinder, the housing having at least one opening communicating with the through-hole and extending in a direction transverse to the axis of the cylinder. This mount can be used as the basis for a number of different radiotherapy systems. One such system comprises a support having a cylindrical bearing surface on which is mounted the cylindrical bearing surface of such a mount, an arm extending from a side of the mount in a direction in line with the axis of the cylindrical bearing surface, the arm comprising a linear accelerator adapted to emit a beam of therapeutic radiation from an end portion of the arm in a direction transverse to and towards the axis of the cylindrical bearing surface. Another possible system comprises a support having a cylindrical bearing surface on which is mounted the cylindrical bearing surface of such a mount, a source of therapeutic radiation fixed to the mount and adapted to emit a beam transverse to and towards the axis of the cylindrical bearing surface though the at least one opening of the mount. Both systems can further comprise one or more of a source of diagnostic radiation, a detector for diagnostic radiation and a detector for therapeutic radiation. In the former, these can be mounted on retractable arms, so as to be selectively retractable into the mount or extendable alongside the linear accelerator. The latter system can further include a cover around the mount, the cover including a concave region extending into the axial through-hole of the mount. | 04-16-2009 |
| 20090069811 | Device and method for fixation of equipment to the head of a patient during neurological diagnosis, therapy or surgery - A device is provided for fixation of equipment to the head of a patient during neurological diagnosis, therapy or surgery, comprising a ring-shaped frame having at least three fixation pins which are attachable against the skull of the patient with a contact force for fixation of the device thereto. At least one connecting means is positioned at a location where the frame has a minimum of displacement due to deformation of the frame when the fixation pins are tightened towards the skull, in order to allow fixation of equipment for diagnosis, therapy or surgery to the frame without they being distorted as a consequence of the deformation of the frame. The invention also relates to a method for fixation of the head of a patient by means of such a device. | 03-12-2009 |
| 20090069661 | METHOD FOR SEPARATING MULTICHANNEL SIGNALS PRODUCED BY AC AND DC SOURCES FROM ONE ANOTHER - The present invention relates to a novel manner of measuring DC fields using a multi-channel MEG or MKG measuring instrument; and on the other hand, to a manner of eliminating from the measurement result the interference signals caused by the DC currents. The invention combines the monitoring system of a testee's movement and the method for motion correction of the measured signals so that the signals produced by the DC currents of a moving testee's are visible in the final measurement result as a static signal component in a conventional MEG or MKG measurement. In that case, in the measurement, it is not necessary to beforehand prepare oneself for measuring the DC fields. | 03-12-2009 |
| 20090013468 | Radiotherapy apparatus - A patient support system comprises a base, an upstanding support, and a couch attached to the support and having a cantilever section extendable beyond the support; the support including a couch drive means to adjust the position of the couch relative to the support; further comprising a support drive means for translationally driving the support relative to the base in the direction of the cantilever section. This removes inaccuracies from patient position measurements that result from changes in the cantilever geometry during movement of the patient from a measuring position to a treatment position. The support drive means can be located in the base or in the support, and allows the patient support system as a whole to be translated, thereby permitting the patient to be moved into and out of an enclosed treatment area without affecting the vertical location of the patient. The only change to the patient position is in the translational position, which can be calibrated by way of fixed end stops for the support drive means. The present invention further relates to a radiotherapy apparatus, comprising a patient support as set out above, and an enclosed treatment area positioned in line with the cantilever section. | 01-15-2009 |
| 20080294386 | Method and Device For Interference Suppression in Electromagnetic Multi-Channel Measurement - The present invention recognises and eliminates from a biomagnetic measurement signal interferences whose source is disposed in the direct vicinity of an object being measured. The invention utilises the SSS method that can be used to separate from one another the signals associated with the internal and external sources of a set of measurement sensors by calculating two series developments. The sources to be examined in the invention and disposed in the so-called intermediate space produce a component to both of the developments, and can, therefore, be detected by means of an analysis to be performed in a time domain. This division into components can be made using the Principal Component Analysis (PCA), the Independent Component Analysis (ICA) or the Singular Value Decomposition. Finally, the clarified interferences in the intermediate space can be eliminated from the measured signal using, for example, the linear algebraic orthogonal projection. | 11-27-2008 |
