RADIOSYNOVECTOMY

• • Intraarticular therapy with radionuclides is widely used in the developed countries and the number of centers providing intraarticular radionuclide therapy is on the rise.
• Radiosynovectomy (RS) is a treatment alternative to surgical and chemical synovectomy in the treatment of rheumatoid arthritis. Among the basic reasons why RS cannot find a wide utilization area is that the radioactivity leaks from the articular and gives extra radiation dose to the other organs. The new approach for the preparation of radioactive particles used in RS, this leakage is minimized and the treatment is realized. With this method, RS changes its place in the agenda.
  
  

The frequency of rheumatoid arthritis is between 2-3% and in women, 4 times more than men.
Synovitis is observed in chronic inflammatory articular diseases. In synovitis, fluid collection, functional impairment of the involved joint and excessive pain occur. If these symptoms cannot be treated with gold based preparations, D-penisilamin, antimalaric, cytostatic, immune suppressive, corticoid and non-corticoid medicines, local therapy methods are used. Among these, the surgical intervention (surgical synovectomy) comes first.

CHEMICAL SYNOVECTOMY
• In today’s modern treatment scheme, treatment with injecting various substances into the joints should be tried before surgical interventions. With this method that we will call as chemical synovectomy, the substances injected in the joint are used for relieving the inflammatory activity in the synovia. Corticosteroid, cytostatic (such as methotrexate), osmium acids and alkali agents (such as thiotepa and nitrogen mustard) and varicosis. Chemical synovectomy gained limited use due to the local cartilage damage and systemic side effects.

SURGICAL SYNOVECTOMY
• In advanced cases, the inflamed articular surface is removed with surgical synovectomy. It is surgically difficult to remove the diseased synovium completely. Furthermore inflammation may recur. It may recur 2-5 years after successful operation. When the symptoms recur, the surgical intervention is contraindicated due to the fibrous tissue and scar formation due to previous surgical attempt.

RADIOSYNOVECTOMY

• Radiosynovectomy (RS), is the injection of radionuclide either in colloid or particule formation intraarticularly. It is an alternative to surgical synovectomy. Beta emitting radionuclides are injected intraarticularly to alleviate synovial inflammation. RS has been published for the first time in 1952. In year 1963, it has been applied with Au-198 by Crook, Mallard and Bywaters. With this method, mostly Yttrium-90, Au-198, Erbium-169, Rhenium-186 and Phosphorus LEGAL REQUIREMENTS P-32 radiocolloids have been used.
• Since radioactive substance is used in this treatment, according to the directives of T.R. Turkey Atom Energy Institute (TAEK), this can be performed only in places with Nuclear Medicine Department license under the responsibility of a Nuclear Medicine Specialist.
• The indication is taken by the specialists of related departments such as rheumatology, orthopedy, physical treatment and hematology and through been consulted with the Nuclear Medicine specialists, the application decision is taken.
• The application is performed by the indication taking specialist and the Nuclear Medicine specialist.
  ATTENTION:
  As of the request of radioactive substance, the application and the management of the waste radioactive substance is under the responsibility of Nuclear Medicine Department licensed by TAEK.
  RADIOPHARMACEUTICALS:
  The licensed radiopharmaceuticals that are used in today’s applications are in 3 types according to the size of the articular: at knee, middle joints and small joints These substances are manufactured at licensed nuclear reactors and audited by International Atom Energy Institute.
  

RADIONUCLIDE TREATMENT FOR ARTICULAR IN KNEE:

USED RADIOPHARMACEUTICAL: Should have been stated by the manufacturer company that it should be in “colloid form used in intra-articular treatment”.
SUBSTANCE: YTTRIUM-90 (90Y) SILICATE/CITRATE COLLOID: Radiopharmaceutical used in knee intra-articular radionuclide treatment.

INDICATIONS:

• Rheumatoid arthritis (with persistent effusion),
• Other inflammatory articular diseases,
• Pigmental villonodular synovitis,
• Hemophilic articular diseases,
  
• Chronic pyrophosphate arthropathy
  

RELATIVE INDICATIONS:

• Persistent effusions after knee prosthesis application,
• Baker cyst,
  
• Active arthropathy
  
• CONTRAINDICATIONS:
  
• Precise contraindication
  
• Pregnancy
  
• Nursing
  

Relative contraindication: Due to the potential risk of the radioactivity, if the advantage is more than the risk, then can be assessed to be applied in children and young patients (below 45 years)

PATIENT SELECTION :

• Regarding the age of the patient, the relative contraindications should be considered.
• The patients in whom the conservative treatment with corticosteroid is performed for 6 months is ineffective are selected.
  

Preparation of the patient :

• Through ultrasound, x-ray or MRI, etc… methods, it is seen that the articular interval, synovia structure and effusion amount has the capability to allow the homogenous allocation of the radiopharmaceutical to be given.
• With scintigraphy, the level of the soft tissue and the active inflammation is determined (3 phase bone and/or 99mTc-HIG scintigraphy)
  

PROCEDURE
In a hygienic environment, the injection is made to the articular through fulfilling the asepsis requirements. Local anesthesia can be helpful. One should be confident that the correct amount of radioactivity is administered and the substance is homogenously distributed in the articular gap.
Submission of corticosteroid together with the radioactivity causes a positive effect. Before the injection needle is withdrawn from the joint, small amount of 0.9% NaCl is given and the needle is washed. With this process, the contamination of substance to the tissue where the needle is inserted is reduced to minimum. At the end of the application, the joint is moved with passive movements and the substance is distributed within the joint. After, the joint is bandaged for the purpose of immobilization, it is recommended that the joint should stay without movement for at least 48 hours.
The injection is performed under scopy. If a contrast substance will be given, then the contrast agents that do not make chelate and can be dissolved in water should be used.

REQUIRED ACTIVITY
It is recommended that in knee articular, Y-90 colloid dose should be given between 148-220 MBq (4-6 mCi) and at 3 ml volume. For more than one articular treatment of the same patient, totally Y-90 colloid dose should not exceed 440 MBq (12 mCi) at once and should not exceed 111-150 MBq (3-4 mCi) at each knee.

INTERACTION WITH DRUGS AND OTHER SUBSTANCES
Chelate forming substances (Such as contrast agents containing EDTA…) may cause the separation of Y-90 from colloid form, the leakage of radioactivity from the joint and the exposure of lymph nodes to radiation. For this reason, in the patients with previous arthrography, the application should be made at least after 8 weeks.

MONITORING OF PATIENT
6-8 weeks after the intra-articular radionuclide treatment; the clinical evaluation containing physical examination, hematologic and bio-chemical parameters, the scintigraphic status of the inflammation, ultrasound or MR imaging is performed.
It should be repeated in the 3rd or 6th month after the clinical examination and ultrasound treatment and once in 12 months.

RETREATMENT
Radionuclide treatment can be repeated after a 6 month period. For the recurrent effusions in the knee joint related to the rheumatoid arthritis, the second injection can be applied after 3 months. The total radioactivity administered within one year should not exceed 750 MBq (20 mCi) Y-90 colloid.