G R Holeman

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High-energy x-ray radiotherapy machines generate neutrons by photonuclear reactions in the target and the treatment head and expose the patient to a neutron flux. In order to evaluate the neutron exposure quantitatively, fast and thermal neutron profiles for 25-MV x-ray beams of the Sagittaire accelerator have been measured. An activation technique, using(More)
High-energy x-ray radiotherapy machines in the supermegavoltage region generate complex neutron energy spectra which make an exact evaluation of neutron shielding difficult. Fast neutrons resulting from photonuclear reactions in the x-ray target and collimators undergo successive collisions in the surrounding materials and are moderated by varying amounts.(More)
Benign hemangiomas and vascular malformations are the most common tumor of infants and children [1]. Skull involvement is rare compared with soft-tissue involvement. A plethora of classifications applied to these lesions has led to an imperfect and suboptimal understanding of them. Burrows et al. [2] describe angiographic differences between hemangiomas and(More)
High-energy x-ray radiotherapy machines produce neutrons by photonuclear reactions which present a potential radiation hazard to the personnel and patient. A series of measurements of the neutron flux from a 25 MV x-ray linear accelerator, inside and outside the treatment room, have been performed using a multisphere spectrometer, Nemo dosimeter, and(More)
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