Publications by authors named "Raymond C Lawson"

Object: Where no society-based or manufacturer guidance on radiation limits to neuromodulation devices is available, this research provides the groundwork for neurosurgeons and radiation oncologists who rely on the computerized treatment plan clinically for cancer patients. The focus of the article is to characterize radiation parameters of attenuation and scatter when an incident therapeutic x-ray beam is directed upon them. At the time of this writing, manufacturers of Neuromodulation products do not recommend direct exposure of the device in the beam nor provide guidance for the maximum dose for these devices.

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Vascular access ports are used widely in the administering of drugs for radiation oncology patients. Their dosimetric effect on radiation therapy delivery in photon beams has not been rigorously established. In this work the effects on external beam fields when any of a variety of vascular access ports is included in the path of a high energy beam are studied.

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Verification of dosimetric data computed by a treatment planning system is necessary in the commissioning process for any clinical software, just as it is necessary for any annual quality assurance testing. Direct verification of the dosimetric data is achievable when calculating the enhanced dynamic wedge (EDW) off-axis ratio at each point of interest. As mathematical models for hand-calculating such factors are still evolving, measurement of these external beam arrangements has proven significantly more accurate.

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