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    CALIBRATION OF VOLUME ACQUIRED IMAGES
    1.
    发明公开
    CALIBRATION OF VOLUME ACQUIRED IMAGES 有权
    校准量采购IMAGES OF

    公开(公告)号：EP2095328A1

    公开(公告)日：2009-09-02

    申请号：EP06829430.5

    申请日：2006-12-08

    申请人： Elekta AB (publ)

    发明人： LONG, Andrew

    IPC分类号： G06T5/40 ,  G06T5/20

    CPC分类号： G06T5/20 ,  G06T5/008 ,  G06T5/40 ,  G06T2207/10081 ,  G06T2207/20012

    摘要： 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. In this way, an image can be obtained from a cone beam CT apparatus and corrected using the voxel intensities from a recent reference image as a norm. Provided that the reference image is relatively recent, there should not be sufficient gross changes in the volume image to affect this process. Changes between the reference and subsequent images such as the movement of internal structures will be preserved since the method compares local histograms and this corrects intensities, not shapes. Likewise, the use of histograms around a local region of the volume image will mean that gently varying artefacts such as the cup artefact will be substantially eliminated. The volume image thus derived can then be used for treatment planning, such as in radiotherapy.

    RADIOGRAPHIC APPARATUS
    3.
    发明公开
    RADIOGRAPHIC APPARATUS 审中-公开
    射线照相装置

    公开(公告)号：EP2073705A1

    公开(公告)日：2009-07-01

    申请号：EP06806172.0

    申请日：2006-10-11

    申请人： Elekta AB (publ)

    发明人： KNOX, Christopher ,  LONG, Andrew ,  BROWN, Kevin

    IPC分类号： A61B6/00 ,  A61N5/10 ,  A61B5/113

    CPC分类号： A61B6/5217 ,  A61B5/113 ,  A61B6/541 ,  A61N5/1064 ,  A61N2005/1061

    摘要： 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 .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.

    摘要翻译： 对于呼吸相关锥束CT扫描，我们已经观察到帧频的改善实际上是不希望的。 因此，我们提出了一种包括辐射束及其检测器的放射线照相设备，其适于在通过要被研究的循环变化对象之后获得该束的二维图像，处理器适于检查图像并在相似点处选择图像 在该周期中，以及用于辐射束的控制装置，该控制装置适于周期性地激活该束。 控制装置可以以0.5和5赫兹之间，更优选1和3赫兹之间的频率激活光束，该频率对应（大致）对应于周期性变化频率的6到10倍的频率。 如果所选择的循环点是其末端，这将有所帮助，因为这些区域的变化率最小。 因此，两个周期之间的轻微不匹配只会产生很小的影响。 通常情况下，对象将是病人，周期性变化将是病人的呼吸循环。

    IMAGING SYSTEMS FOR IONISING RADIATION
    5.
    发明公开
    IMAGING SYSTEMS FOR IONISING RADIATION 有权
    成像系统，电离辐射

    公开(公告)号：EP2061557A1

    公开(公告)日：2009-05-27

    申请号：EP06792024.9

    申请日：2006-09-13

    申请人： Elekta AB (publ)

    发明人： LONG, Andrew ,  BROWN, Kevin ,  ALLEN, John

    IPC分类号： A61N5/00

    CPC分类号： A61N5/1049 ,  A61B6/032 ,  A61B6/4488 ,  A61N2005/1054

    摘要： 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.