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MO‐FF‐A2‐05: A Novel Stereotactic Radiosurgical Device for the Treatment of Age‐Related Macular Degeneration (AMD)
Author(s) -
Chell E,
Firpo M,
Bolch W,
Lee C,
Hanlon J
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3182287
Subject(s) - macular degeneration , fiducial marker , radiosurgery , collimated light , retina , lens (geology) , sclera , medicine , ophthalmology , computer science , radiation therapy , optics , physics , surgery , radiology , laser
Purpose: Age‐related Macular Degeneration (AMD) is the leading cause of blindness in people over 65 in the U.S. It is caused by a proliferation of capillaries in the retina and can result in profound and rapid loss of central vision. As a neovascular disease, it has been shown to be susceptible to radiotherapy. Recently, a 100kVp tabletop stereotactic radiosurgical (SRS) device has been developed to deliver highly‐collimated beams of X‐rays to the fovea to treat AMD. This study is an evaluation of that system. Method and Materials: The device delivers a three‐port, 16Gy single fraction dose to the macula. Using a suction‐enabled contact lens assembly (“the I‐Guide”) to stabilize the eye, three 4mm diameter beams of 100kVp x‐rays are delivered to the fovea, directed by a positioning robot. The beams enter the eye through the sclera and avoid the radio‐sensitive lens. The I‐Guide includes reflective fiducials that are monitored by cameras, and the real‐time position of the beam on the retina is calculated from the fiducial positions. Because of uniformity across adult eye populations, a class‐solution treatment plan was implemented using a single parameter (eye length). Software manages treatment time and automatic gating of beam in case of excessive eye motion. A clinical trial is underway. Results: 100kVp proves an optimal energy for ophthalmic radiotherapy. A therapeutic dose to the retina can be delivered with negligible impact to the brain and the scleral entry dose is well‐tolerated. The scatter from the narrow beam is minimal to sensitive structures in the eye. Submillimeter targeting precision was demonstrated in the lab and in the clinic. Submillimeter motion‐management was also demonstrated. Conclusion: The eye‐specific SRS device shows great promise for providing a precise and non‐invasive method of treating AMD. Research sponsored by Oraya Therapeutics.