A system including a support panel and a fixation device for use in radiation therapy is disclosed. The support panel comprises a generally planar member that is arranged to be disposed adjacent an apparatus for producing a radiation beam to support a portion of the patient to which the radiation beam will be directed. The fixation device is arranged to be releasably secured to the support panel to hold the portion of the patients body at a desired position. The fixation device includes attachment components which enable the releasable securement of the fixation device to the support panel without creating any attenuation discontinuities of a radiation beam passing therethrough.
