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A Compound Refractive Lens for Radiation Oncology Megavoltage X-Rays

R Rademacher1*, (1) Genesis Healthcare Partners, San Diego, CA


(Sunday, 7/14/2019)  

Room: ePoster Forums

Purpose: Conventional wisdom in medical physics holds that the megavoltage X-rays used in radiation oncology cannot be manipulated. However, advancements in the field of x-ray optics over the last two decades may prove this is no longer the case. By creating a compound refractive lens to collimate and focus mega-voltage x-rays, radiation oncology linear accelerator beams can be more effectively controlled.

Methods: The test will consist of recording an open field, a blocked field, and the lens field If successful, we expect to see a “barbell� pattern insofar as the central lens field has been collimated while the outside blocked and open fields remain divergent. A success would also show larger dose gains and smaller penumbra in the lens field compared to the open and closed fields. The original CRL design consisted of cylindrical holes drilled into aluminum with the interstices between the holes functioning as the lens. We will use the same design for our prototype and characterize it with three parameters: focal length, transmission, and gain. This lens will be created by an independent manufacturer and tested on a LINAC at a Genesis Healthcare Partners.

Results: This experiment has not been funded yet. If funding is obtained in time, the results of the experiment will be presented at the meeting. Otherwise, an outline of the theory and experiment will be presented.

Conclusion: If successful, this lens will result in higher dosage gains, smaller penumbras, reduced normal tissue irradiation, and better field conformality, all of which lead to better patient outcomes.


Field Shaping, Linear Accelerator, Microfocus X-ray


TH- External beam- photons: Small/nonstandard field experimental dosimetry

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