Basic Guidelines for the use of Eye Physics Technologies

Guidelines for the Eye Physics procedure in general:

  1. The accuracy of treatment planning using the Eye Physics Plaque Simulator software depends upon the quality of the CT, ultrasound and fundus images provided to the planner, and the training and experience of the planner.
  2. The better the image quality and the greater the experience of the planner in regard to interpreting the images, the more accurate will be the overall results.
  3. Eye Physics offers numerous training examples and tutorials on the eye physics web site and also provides individual consultation and training both via the internet or on-site upon request...
  4. CT (or MR) images covering the orbits at ≤ 3 mm slice spacing should be provided in DICOM format for multiplanar reconstructions (MPR) of the eye and tumor using Osirix software.
  5. Ultrasound images of the tumor provide the best measure of tumor height.
  6. A wide angle fundus image, or a collage of fundus images, including the optic disc, the fovea, and as much of the tumor as can be photographed provides the best measure of the shape of the tumor base.
  7. Each institution is expected to provide its surgeons whatever tools they deem necessary for the surgical placement of eye plaques. Eye Physics recommends at minimum obtaining an indirect ophthalmoscope, a toric meridian angle marker and a Castroviejo caliper to mark suture coordinates on the eye.
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Guidelines for Eye Physics dosimetry planning:

  1. The institution is responsible to provide a computer capable of running the MacOSX 10.8 or later operating system, a flatbed scanner if images will be provided in film or printed formats, and all required 3rd party software products including Adobe Photoshop and Osirix.
  2. A typical prescription and dose rate for choroidal melanoma is 85 Gy delivered over 4 to 7 days but this is actually a choice of the local physicians.
  3. Select a plaque and radionuclide source loading pattern that encloses the tumor apex and at least a 2 mm retinal margin surrounding the tumor base within the prescribed (e.g. 85 Gy) isodose surface.
  4. Try to reduce dose to the macula, fovea and optic disc without compromising tumor coverage. This is achieved by experimenting with variations of source location, strength and plaque shape.
  5. To rent a preloaded, pre-sterilized plaque, print the treatment plan as a .pdf file and email it to your IsoAid representative several days before you need delivery. The rental plaque will arrive, ready to implant, with return shipping instructions and documents.
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Guidelines for Eye Physics surgical positioning:

  1. The accuracy of the calculated suture coordinates depends on the quality of the CT, ultrasound and fundus images provided and the training and experience of the planner.
  2. The Eye Physics Plaque Simulator calculated suture coordinates for the plaque are to be considered only as a guide to plaque placement.
  3. The surgeon should use a toric meridian angle marker and a Castroviejo caliper to mark the suture coordinates on the eye.
  4. The surgeon MUST ALWAYS visually confirm the placement using a dummy plaque and indirect ophthalmoscopic observation. If the fit isn't as planned, the surgeon MUST manually adjust the placement coordinates to achieve the plan objectives...
  5. Eye Physics plaques are cast from 18K gold alloy. Radionuclide seeds are glued into individually collimating slots in the plaque face using a heat tolerant, medical instrument approved cyanoacylate adhesive.
  6. Should a preloaded, presterilized Eye Physics plaque or dummy plaque lose its sterility due to accidental mishandling prior to or during surgery, it may be steam resterilized on-site using a 4 to 10 minute flash cycle.
  7. Return rented plaques to IsoAid as soon as possible following removal from the patient. Return instructions, including sterilzation procedures, are included with the return shipping documents...
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