| 摘要 |
A method of intensity-modulating a beam of radiation from a radiation source is provided, the method including the steps of: a) providing a collimator having a window which allows the passage of radiation from the radiation source and which defines when viewed from the radiation source a two-dimensional array of bixels, the collimator further having a plurality of independently movable radiation attenuators which are constrained to move along columns or rows of the array to block selected bixels thereof, whereby, within each column or row along which the attenuators are movable, at least one arrangement of the respective attenuator(s) results in a pair of open bixels sandwiching a blocked bixel or line of blocked bixels; b) positioning the collimator in the path of the radiation source; and c) repeatedly: positioning the radiation attenuators within the window to form at each repeat a different pattern of bixels; and irradiating the collimator, until a predetermined pattern of radiation intensities for the beam of radiation has been delivered through the collimator. A corresponding apparatus for producing an intensity-modulated beam of radiation which is operable in accordance with the above method, and a method of radiotherapy treatment performed on a human or animal body comprising subjecting the body to an intensity-modulated beam of radiation formed using the above method are also provided.
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