The patient is automatically moved head first into the CT gantry, and the x-ray tomogram is acquired. Now the patient is automatically moved through the PET gantry, which is mounted in parallel with the CT gantry, and the PET slices are acquired. The patient may now leave the device, and the PET-CT software starts reconstructing and aligning the PET and CT images.
Diagnostic Procedures. Three common diagnostic procedures, tonometry, visual field tests, and ophthalmoscopy, enable ophthalmologists to screen patients for glaucoma. To make a definitive diagnosis, ophthalmologists often use all 3 procedures as part of an overall eye examination. The procedures are simple, relatively quick, and virtually painless.
A visual field test is performed at the initial visit or as soon as glaucoma is suspected. It evaluates vision loss due to glaucoma, damage to the visual pathways of the brain, and other optic nerve diseases. When glaucoma is diagnosed the visual field data is used to determine the severity of disease. This staging information is useful in choosing a target intraocular pressure and determining follow-up.