Radiation synovectomy using 188Re-tin colloid improves knee synovitis as shown by MRI in refractory rheumatoid arthritis.
BACKGROUND
Radiation synovectomy is a useful local treatment for patients with refractory synovitis. We previously demonstrated the efficacy and safety of Re-tin colloid for treating rheumatoid arthritis patients with refractory knee synovitis. This open-label, prospective controlled study investigates magnetic resonance imaging (MRI) changes as well as clinical response in knees after receiving different radioactivities of intra-articular Re-tin colloid.


METHODS
Sixteen patients with rheumatoid arthritis refractory to intra-articular corticosteroid therapy were treated with intra-articular injection of Re-tin colloid (555 MBq in six patients, 740 MBq in five, and 925 MBq in five). Contralateral knees were used as controls. Treatment efficacy and safety were evaluated 1, 3 and 6 months later. We compared the changes of synovial thickening and joint effusion between baseline and 6 months. Synovial thickness was measured by gadolinium-enhanced MRI.


RESULTS
Pain intensities on a visual analogue scale were significantly lower (median pain reduction, 78.9%; P=0.0001), joint swelling improved (median, -1.5; P=0.001), range of motion increased (median, 6 degrees , P=0.005), and joint tenderness decreased (median, -1; P=0.005) in treated knees after 6 months. The control knees did not show any significant clinical improvement. At 6 months after therapy, synovial thickening of treated knees improved in 87.5% of patients (P<0.001), and synovial thicknesses were significantly decreased in treated knees (P=0.0067). Furthermore, reduction in synovial thickness was most noticeable in the group treated with 925 MBq (P=0.007). No abnormalities in leukocyte or platelet counts, liver function tests, or urine analysis were observed.


CONCLUSIONS
Radiation synovectomy using Re-tin colloid in refractory rheumatoid arthritis patients improved MRI findings as well as clinical parameters.
Shin
Kichul
K
Department of Internal Medicine, Seoul National University College of MedicineSeoul, South Korea.
Lee
Jung Chan
JC
Choi
Hyo Jin
HJ
Jeong
Jae Min
JM
Son
Miwon
M
Lee
Yun Jong
YJ
Lee
Eun Bong
EB
Hong
Sung Hwan
SH
Song
Yeong Wook
YW
D001172:Arthritis, Rheumatoid / Q000473:pathology* / Q000532:radiotherapy*; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007269:Injections, Intra-Arterial; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000532:radiotherapy*; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D012211:Rhenium / Q000008:administration & dosage*; D013585:Synovitis / Q000473:pathology* / Q000532:radiotherapy*; D014001:Tin / Q000008:administration & dosage*; D017211:Treatment Failure; D016896:Treatment Outcome
C481499:(188)Rhenium tin-colloid; D019275:Radiopharmaceuticals; D012211:Rhenium; D014001:Tin