Yttrium-90 silicate is used to treat chronic synovitis, which is an inflammation of the synovial membrane in a joint, such as the knee. It is an alternative to undergoing a surgical synovectomy. It may also be used to treat other conditions that result in joint pain. The Yttrium Silicate is injected directly into the affected joint as a colloidal liquid. It will stay there and give a radiation dose that should help to alleviate pain and reduce inflammation.
Patients may either be treated on an outpatient or an inpatient basis (an overnight stay may be deemed appropriate). The treatments are performed in the Nuclear Medicine department of the Royal Surrey County Hospital, but patients have a leg cast made in another department before arriving in Nuclear Medicine. It is important that the patient cannot move their leg to ensure that once injected, the radionuclide does not move around or out of the joint area.
Local anaesthetic is injected into joint and if required, fluid is drained from the area. A steroid injection is given followed by the Yttrium injection. The knee is immobilised and secured in the cast. This is immediately followed by a scan on a gamma camera in Nuclear Medicine. This is used to check where the radioisotope is within the joint.
Upon discharge a Medical Physicist gives some Radiation Protection precautions that should be followed as the radioisotope is radioactive. These precautions are, however, quite minimal. Patients need to be driven home so that the joint can remain immobilised. Bed rest is required for 72 hours after the procedure to keep weight off the affected joint.