Radiosynovectomy's clinical applications and cost effectiveness: a review

Safety and Efficacy of Radiosynoviorthesis: A Prospective Canadian Multicenter Study

Radiosynoviorthesis is approved in several European countries and the United States to treat refractory synovitis in many inflammatory joint diseases, such as rheumatoid arthritis, spondyloarthropathies, and other arthritic joint diseases. No radiopharmaceuticals for radiosynoviorthesis are currently approved in Canada. The aim of this Health Canada-approved trial was to demonstrate the safety and efficacy of radiosynoviorthesis. Methods: Between July 2012 and November 2017, we conducted a multicenter, prospective, interventional Canadian trial. Patients (n = 360) with synovitis refractory to standard treatments after failing 2 intraarticular glucocorticoid injections were included. They were followed up at 3, 6, and 12 mo. Outcome measures included adverse events (AEs) and clinical signs of synovitis (pain, swelling, and joint effusion) measured with the Health Assessment Questionnaire Disability Index, the Disease Activity Score, and the Visual Analog Scale. Results: In total, 392 joints were treated, including those reinjected after 6 mo (n = 34). Of these, 83.4% (327/392) were injected with [90Y]Y-citrate for the knees and 9.9% (39/392) with [186Re]Re-sulfide for medium-sized joints. Of the joints treated, 82.7% (324/392) were knees. Fifty-five AEs, most of them of mild grade, occurred and resolved without sequelae and were not life-threatening. The incidence of radiosynoviorthesis-related AEs was 9.4% (34/360). The proportion of patients showing an improvement in synovitis symptoms after radiosynoviorthesis was significant at 3 mo and was maintained up to 12 mo (P < 0.001). Conclusion: This study confirmed the safety of radiosynoviorthesis in the treatment of patients with synovitis refractory to standard treatments. There is evidence of sustained clinical efficacy at 12 mo, suggesting that radiosynoviorthesis is an effective treatment for improving synovitis symptoms.

Radiosynovectomy in routine care: an old tool with modern applications

Objectives:

Radiosynovectomy can be an effective treatment for difficult-to-treat monoarthritis resistant to systemic and local standard therapy. The objective of our study was to determine predictors of good response to radiosynovectomy in routine care and give an overview of this underused technique.

Methods:

Retrospective observational study of all the patients who underwent radiosynovectomy during a 6-year inclusion period. All the procedures were ultrasound guided and the radiopharmaceutical used was chosen according to joint size. The patient was considered to have an effective response to radiosynovectomy if the attending physician reported a positive outcome and there was no need to increase local and or systemic treatment due to arthritis in the affected joint during the next 12 months following the procedure.

Results:

We included 67 patients who underwent radiosynovectomy in the knee (73.1%), wrist (16.4%), and elbow (10.5%). Overall, 44 (65.7%) procedures were considered effective. In the multivariate analysis, infiltration of wrists (odds ratio = 0.192; confidence interval = 0.046–0.79) and pigmented villonodular synovitis (odds ratio = 0.13; confidence interval = 0.021–0.82) were independently associated with a noneffective response. No patients experienced complications associated with radiosynovectomy during follow-up.

Conclusion:

Infiltrations of wrists with joint damage seem less likely to have a response to radiosynovectomy. In pigmented villonodular synovitis, radiosynovectomy as an adjuvant therapy for relapse might not be effective when performed more than 6 months after surgery. Overall, radiosynovectomy is an effective and safe treatment for persistent monoarthritis.

Radioisotope Synoviorthesis in the Control of Refractory Synovitis in Castilla-La Mancha. A 10-year Experience

Our hospital is the nuclear medicine referral hospital for radioisotopic synoviorthesis for all of Castilla-La Mancha.

OBJECTIVE

To describe the experience in the performance of radioisotopic synoviorthesis for arthritis refractory to other treatments in our hospital.

METHODOLOGY

Observational, descriptive and cross-sectional study protocolised through the review of the database of radioisotopic synoviorthesis performed between 2007 and 2017. Previous clinical data were collected (age, sex, pathology, previous treatments, previous infiltration and affected joint), and progress at 6 months after administering the isotope. An Excel database was created for a frequency analysis with SPSS 21.

RESULTS

30 radiosynovitis interventions were performed. The most frequent pathologies in this order were: pigmented villonodular synovitis (40%), rheumatoid arthritis (23.3%), spondyloarthritis (13.3%), osteoarthritis (10%) and nonspecific arthritis (6.7%), followed by systemic lupus erythematosus and gout. After 6 months, 56.7% of the patients improved compared to 36.7% who remained the same. Likewise, none of them presented complications related to the procedure. Six point six percent of the patients were lost to follow-up.

DISCUSSION AND CONCLUSIONS

In patients with episodes of recurrent arthritis with associated joint effusion in one or two joints, refractory to systemic treatments, to local infiltrations with corticosteroids and for patients for whom other treatments may be contraindicated, we must consider the possibility of performing an isotope radiosinoviortesis, as it is a simple, safe technique with a success rate of more than 50%.

Barium titanate microparticles as potential carrier platform for lanthanide radionuclides for their use in the treatment of arthritis

Since the inception of radiation synovectomy, a host of radioactive colloids and microparticles incorporating suitable therapeutic radionuclides have been proposed for the treatment of arthritis. The present article reports the synthesis and evaluation of barium titanate microparticles as an innovative and effective carrier platform for lanthanide radionuclides in the preparation of therapeutic agents for treatment of arthritis. The material was synthesized by mechanochemical route and characterized by X-ray diffraction, scanning electron microscopy, surface area, and particle size distribution analyses. Loading of lanthanide radionuclides (¹⁶⁶ Ho, ¹⁵³ Sm, ¹⁷⁷ Lu, and ¹⁶⁹ Er) on the microparticles was achieved in high yield (> 95%) resulting in the formulation of loaded particulates with excellent radiochemical purities (> 99%). Radiolanthanide-loaded microparticles exhibited excellent in vitro stability in human serum. In vitro diethylene triamine pentaacetic acid challenge study indicated fairly strong chemical association of lanthanides with barium titanate microparticles. Long-term biodistribution studies carried out after administration of ¹⁷⁷ Lu-loaded microparticles into one of the knee joints of normal Wistar rats revealed near-complete retention of the formulation (> 96% of the administered radioactivity) within the joint cavity even 14 days post-administration. The excellent localization of the loaded microparticles was further confirmed by sequential whole-body radio-luminescence imaging studies carried out using ¹⁶⁶ Ho-loaded microparticles.

Short-term clinico-radiological outcome of chronic knee synovitis among haemophilia A patients post phosphorus-32 radiosynoviorthesis

PURPOSE

Various modes of therapy have been directed at breaking the vicious cycle at early stage of synovitis in haemophilia patients. This study was planned to assess the short-term clinico-radiological outcome of chronic knee synovitis among haemophilia A patients post phosphorus-32 (P-32) radiosynoviorthesis.

METHODS

P-32 samarium radiocolloid was injected into the knee and patients were followed up at 1 and 3 months, respectively. Clinical outcomes was assessed using Tegner Lysholm scores (TLSs), Modified Knee Society Clinical Rating System (MKSS) score and circumference of the knee joint. The radiological outcomes were assessed using X-ray, ultrasonography and bone scan.

RESULTS

Among the fifteen haemophilia A patients studied, there was statistically significant difference in TLS ( χ²(2) = 27.887 and p value < 0.001), MKSS scores ( χ²(2) = 27.745 and p < 0.001) and circumference of the knee joint ( χ²(2) = 21.333 and p < 0.001) at preoperatively, 1- and 3-month follow-up. There were no changes noted in follow-up X-rays compared with the preoperative X-ray. Ultrasonography showed that clinical improvement was more in suprapatellar and medial parapatellar regions in the last 2 months compared to the first month of follow-up. Post P-32 bone scan showed marked decrease in uptake in the affected knee joint suggestive of radio ablation of synovial tissue.

CONCLUSION

P-32 radiosynoviorthesis done for chronic synovitis among haemophilia A patients showed significant improvement in both clinical and radiological parameters. Ultrasonography can be utilized as non-invasive radiological modality for follow-up of P32 response for knee joint.

Lu-177-Labeled Zirconia Particles for Radiation Synovectomy

The present article describes the preparation of β-emitter lutetium-177-labeled zirconia colloid and its preliminary physicochemical and biological evaluation of suitability for local radionuclide therapy. The new (177)Lu-labeled therapeutic radiopharmaceutical candidate was based on the synthesis mode of a previously described zirconia nanoparticle system. The size and shape of the developed radiopharmaceutical compound were observed through a scanning electron microscope and dynamic light scattering methods. The radiocolloid had a 1.7 μm mean diameter and showed high in vitro radiochemical and colloid size stability at room temperature and during the blood sera stability test. After the in vitro characterizations, the product was investigated in the course of the treatment of a spontaneously diseased dog veterinary patient's hock joint completed with single-photon emission computed tomography (SPECT) imaging follow-up measurements and a dual-isotope SPECT imaging tests with conventional (99m)Tc-methanediphosphonic acid bone scintigraphy. In the treated dog, no clinical side-effects or signs of histopathological changes of the joints were recorded during the treatment. SPECT follow-up studies clearly and conspicuously showed the localization of the (177)Lu-labeled colloid in the hock joint as well as detectable but negligible leakages of the radiocolloid in the nearest lymph node. On the basis of biological follow-up tests, the orthopedic team assumed that the (177)Lu-labeled zirconia colloid-based local radionuclide therapy resulted in a significant and long-term improvement in clinical signs of the patient without any remarkable side-effects.

Radiolanthanide-loaded agglomerated Fe3O4 nanoparticles for possible use in the treatment of arthritis: formulation, characterization and evaluation in rats

This investigation reports the preparation of agglomerated Fe₃O₄ nanoparticles and evaluation of its utility as a viable carrier in the preparation of radiolanthanides as potential therapeutic agents for the treatment of arthritis. The material was synthesized by a chemical route and characterized by XRD, FT-IR, SEM, EDX and TEM analysis. The surface of agglomerated particle possessed ion pairs (-O^-:Na⁺) after dispersing particles in a NaHCO₃ solution at pH = 7 which is conducive for radiolanthanide (*Ln = ⁹⁰Y, ¹⁵³Sm, ¹⁶⁶Ho, ¹⁶⁹Er, ¹⁷⁷Lu) loading by replacement of Na⁺ ions with tripositive radiolanthanide ions. Radiolanthanide-loaded particulates exhibited excellent in vitro stability up to ∼3 half-lives of the respective lanthanide radionuclides when stored in normal saline at 37 °C. The radiochemical purities of the loaded particulates were found to be retained to the extent of >70% after 48 h of storage when challenged by a strong chelator DTPA present at a concentration as high as 5 mM, indicating fairly strong chemical association of lanthanides with agglomerated Fe₃O₄ nanoparticles. Biodistribution studies of ⁹⁰Y and ¹⁶⁶Ho-loaded particulates carried out after intra-articular injection into one of the knee joints of a normal Wistar rat revealed near-complete retention of the radioactive preparations (>98% of the administered radioactivity) within the joint cavity even after 72 h post injection. This was further confirmed by sequential whole-body radio-luminescence imaging. These experimental results are indicative of the potential use of radiolanthanide-loaded agglomerated Fe₃O₄ nanoparticles for the treatment of arthritis.

The use of 185 MBq and 740 MBq of 153-samarium hydroxyapatite for knee synovectomy in haemophilia

The penetration of beta energy of 153-samarium (¹⁵³Sm) (0.8 MeV) is not only appropriate for synovectomy of median articulations but is possible to improve the radiobiological effect using increased activities. The aim of this study was to assess the effectiveness of 185 MBq and 740 MBq of 153-samarium hydroxyapatite (¹⁵³Sm-HA) in knees of haemophilic patients. Thirty-one patients – 36 knees, 30 males, were divided into two groups without coinjection of corticosteroid: A – 14 patients (17 knees) treated with intra-articular dose of 185 MBq of ¹⁵³Sm-HA, average age 23 years; B – 17 patients (19 knees) with 740 MBq of ¹⁵³Sm-HA, average age 21.3 years. The evaluation before and after 1 year of synovectomy used the following criteria: reduction in the number of haemarthroses and use of the coagulation factor and improvement in articular motility. Adverse-effects occurrence was considered too. Early and late scintigraphic studies were performed after synoviorthesis and no joint immobilization was recommended. The reduction in haemarthrosis and use of coagulation factor were: group 1 – 31.3% and 25%; group 2 – 81.5% and 79% with P < 0.001 respectively; no significant improvement in knees motility was noted for both groups. Four cases of mild reactional synovitis were observed in each group. The scintigraphic control showed homogenous distribution of the radiopharmaceuticals with no articular escape; the material was considered safe by its permanence in the articulation. We have significant improvement in the synovectomy of haemophilic knees with 740 MBq of ¹⁵³Sm-HA; the less penetration of its beta radiation was compensated by the increased biological effect with the higher used activity.

Reactor production and electrochemical purification of (169)Er: a potential step forward for its utilization in in vivo therapeutic applications

INTRODUCTION

The aim of the present study was to develop and demonstrate a viable method for the reactor production of (169)Er with acceptable specific activity using moderate flux reactor and its purification from (169)Yb following electrochemical pathway based on mercury-pool cathode to avail (169)Er in radionuclidically pure form essential for its therapeutic use.

METHODS

Erbium-169 was produced in reactor by neutron bombardment of isotopically enriched (98.2% in (168)Er) erbium target at a thermal neutron flux of ~8×10(13) n.cm(-2).s(-1) for 21 d. A thorough optimization of irradiation parameters including neutron flux, irradiation time and target cooling time was carried out. The influence of different experimental parameters for the quantitative removal (169)Yb from (169)Er was investigated, optimized and based on the results; a two-cycle electrochemical separation procedure was adopted. The suitablility of purified (169)Er for application in radiation synovectomy and bone pain palliation was ascertained by carrying out radiolabeling studies with hydroxypaptite (HA) particles and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminomethylene phosphonic acid (DOTMP), respectively.

RESULTS

Thermal neutron irradiation of 10mg of isotopically enriched (98.2% in (168)Er) erbium target at a flux of ~8×10(13) n.cm(-2).s(-1) for 21 d followed by a two-step electrochemical separation of (169)Yb impurity yielded ~3.7GBq (100mCi) of (169)Er with a specific activity of ~370MBq/mg (10mCi/mg) and radionuclidic purity of >99.99%. The reliability of this approach was amply demonstrated by performing several production batches, where the performance of each batch remained consistent. The utility of the purified (169)Er was demonstrated in the radiolabeling studies with HA particles and DOTMP, wherein both the radiolabeled products were obtained with high radiolabeling yield (>99%).

CONCLUSIONS

A viable strategy for the batch production and purification of (169)Er, suitable for therapeutic applications, has been developed and demonstrated.

The efficacy of magnetic resonance imaging and x-ray in the evaluation of response to radiosynovectomy in patients with hemophilic arthropathy

Objective: We aimed to assess the role of Magnetic Resonance Imaging (MRI) and X-Ray in the evaluation of response to radiosynovectomy (RS) in patients with hemophilic arthropathy.

Material and Methods: Eleven patients who suffered from hemophilic arthropathy with a mean age of 11.7 (range between 7-15) were included in this study. 148-185 MBq Yttrium 90 silicate (Y-90) was administered intraarticularly to ten knee joints and one patient was treated with intraarticular 74 MBq Rhenium 186 (Re-186) injection into his ankle. Before radiosynovectomy, plain anteroposterior and lateral X-rays of the target joints were obtained by standard technique. The follow-up MRI and X-ray studies of the patients were done 6 months after RS. Pettersson hemophilic arthropathy scales were utilized to stage the condition of the joints on plain X-ray and classification of the investigated joints on MRI were done according to Denver score. The clinical assessment of the efficacy of the RS was made with the comparison of the average bleedings before and after the intervention.

Results: During the 6-month follow-up period after RS, an improvement in number of hemarthrosis 75% or greater compared with the prior six months occurred in six joints (54.5%). The Pettersson scores worsened in 1/11 (9%), remained unchanged in 9/11 (81.8%), and improved in 1/11 (9%) joints. At the 6-month follow-up, the MRI score worsened in one (9%) and was unchanged in 10/11 joints (90.9%).

Conclusion: MRI is a more sensitive tool than plain radiography for evaluating and follow-up of joint disease in persons with hemophilia, but both methods don’t show correlation with the therapeutic response

Conflict of interest:None declared.

A long term results of external beam radiation therapy in hemophilic arthropathy of the ankle in children

Bleeding into joint space is critical to develop hemophilic arthropathy. To reduce the frequency of bleeding in the ankle joint of children with hemophilic arthropathy, low dose external beam irradiation was performed for 37 patients. Among them, 35 patients followed-up for longer than 1 yr (median 87 months) were enrolled for analysis. The average number of bleedings per month was 3.6 during one year prior to radiation therapy. After radiation therapy, it was decreased to 2.1 during the first year, after then it was maintained in the range of 1.0 to 1.5 until the tenth year. The bleeding frequency was reduced to 42% at the first year and it was maintained in the range of 58% to 73% from the second to the tenth year. Especially the patients who had 3 or more bleedings per month, and who had MRI score more than 3 showed significant decreases. During the follow-up period, growth disturbances and secondary malignancies were not found. External beam radiotherapy can be considered for the hemophilic patients with surgical or isotope therapies are not amenable.

Radioisotope synoviorthesis with Holmium-166-chitosan complex in haemophilic arthropathy

Radiosynoviorthesis is a safe and easy method for synovectomy in haemophilic arthropathy. Various agents have been used in radiosynoviorthesis, especially newly developed agent Holmium-166-chitosan complex has good clinical outcome. This study analysed clinical results and radiologic evaluation of radioisotope synoviorthesis using Holmium-166-chitosan complex in haemophilic arthropathy. From March 2001 to December 2003, 58 radiosynoviorthesis were performed in 53 haemophiliacs. The average age at procedure was 13.8 years. The Arnold and Hilgartner stage of the patients was from I to IV. Holmium-166-chitosan complex was injected in 31 ankle joints, 19 elbow joints and 8 knee joints. Average follow-up was 33 months since primary procedure. The range of motion of each joint, frequency of intra-articular bleeding and factor dose used were analysed for clinical assessment. There was no significant improvement of range of motion in affected joints. After procedure, the average frequency of bleeding of the elbow joint has decreased from 3.76 to 0.47 times per month, the knee joint from 5.87 to 1.12 times per month, and the ankle joint from 3.62 to 0.73 times per month respectively (P < 0.05). After treatment, the average coagulation factor dose injected was significantly decreased to 779.3 units per month from 2814.8 units per month before treatment (P < 0.001). Radioisotope synoviorthesis with Holmium-166-chitosan complex in haemophilic arthropathy is a very safe and simple procedure with the expectation of a satisfactory outcome without serious complication. It has excellent bleeding control effect on target joint and the need for substitution of coagulation factor concentrate can be reduced.

Percutaneous radionuclide ablation of axial aneurysmal bone cysts

OBJECTIVE

The purpose of our study was to retrospectively examine the efficacy of intralesional injection of 32P chromic phosphate, a beta-emitting colloidal radiopharmaceutical, in the treatment of aneurysmal bone cysts of the axial skeleton. Five patients with large aneurysmal bone cysts were managed with injection of 32P chromic phosphate into their tumors under CT guidance. With only a single minor complication, all lesions were observed to ossify on follow-up CT, with an average follow up of 2 years.

CONCLUSION

CT-guided injection of axial aneurysmal bone cysts with 32P chromic phosphate leads to excellent local lesion control. In addition, the morbidity associated with this procedure is lower than that associated with surgical or other nonsurgical treatments.

Arthroscopic synovectomy in rheumatoid arthritis of wrist

The wrist is the most commonly involved region of the upper extremity in rheumatoid arthritis (RA). Because the wrist joint becomes involved early during the disease course and its involvement rapidly progresses, and because the disabilities associated with progressive RA are significant, early and adequate treatment must be introduced to prevent disease progression. Various treatment methods can be employed to treat RA wrists based on radiological and clinical findings. Arthroscopic synovectomy is recommended for pain relief and functional recovery in early stage RA, and is also helpful in advanced staged RA with Larsen stage III. However, arthroscopic synovectomy is not recommended as an effective method of treatment for all patients with advanced radiographic changes. Nevertheless, arthroscopic synovectomy may delay the need for complex surgery, such as wrist arthrodesis or total wrist arthroplasty in selective cases. Although arthroscopic synovectomy of the wrist cannot improve grip strength or range of motion, it can reduce wrist pain and improve function, and thus facilitate return to work.

Colloidal 90Y used for radiation synovectomy decreases the viability of chondrocytes in human cadaveric samples

OBJECTIVE

To analyse the early effect of colloidal 90Y beta irradiation, as used for radiation synovectomy (RSV), on the viability of human chondrocytes in an ex-vivo model.

METHODS

Twenty osteochondral plugs (6 mm in diameter) were procured from femoral condyles of an adult male donor and stored in normal saline at 4 degrees C. The cartilage surfaces of 10 plugs were contaminated with colloidal 90Y citrate corresponding to the standard knee RSV dose (185 MBq) matched for the sample size (430 kBq). The remaining 10 plugs served as controls. At days 1, 2, 3, 6 and 13, two osteochondral plugs from each group were stained for viability with live/dead probes and scanned under a confocal laser microscope. The ratios of viable (green channel) and non-viable (red channel) pixels were acquired in four cartilage depth regions and statistically analysed with a regression model.

RESULTS

The irradiation did not significantly alter the viable/non-viable pixel ratio during the first 2 days, but longer exposures led to a significant and time progressive reduction from 8.7% (day 3) to 12.5% (day 13). The ratio was less affected deeper in the cartilage, where it increased about 1% for every 100 microm from the surface.

CONCLUSIONS

Surface exposure of human cadaveric cartilage to a therapeutic dose of colloidal 90Y decreased chondrocyte viability, expressed as the viable/non-viable pixel ratio, in the early post-irradiation period. The findings established in the ex-vivo simulation may reflect the changes in knee cartilage occurring after RSV therapy.

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.

CONCLUSION

Radiation synovectomy using Re-tin colloid in refractory rheumatoid arthritis patients improved MRI findings as well as clinical parameters.

Preparation and preliminary biological evaluation of 177Lu-labelled hydroxyapatite as a promising agent for radiation synovectomy of small joints

AIM

Lutetium-(177)Lu) is considered to be a promising radionuclide for use in radiation synovectomy of small-sized joints owing to its favourable decay characteristics [t(1/2)=6.73 days, E(beta)(max)=0.49 MeV, E(gamma)=113 keV (6.4%), 208 keV (11%)] and feasible and cost-effective production route. Hydroxyapatite particles are regarded as one of the most suitable carriers for applications in radiation synovectomy, and labelling with (177)Lu has been envisaged. The present work describes the preparation and preliminary biological evaluation of (177)Lu-labelled hydroxyapatite particles.

METHODS

(177)Lu-labelled hydroxyapatite particles were prepared using (177)Lu produced by thermal neutron irradiation of a natural (2.6% (177)Lu) Lu(2)O(3) target and hydroxyapatite particles (particle size, 2-10 microm) prepared in-house. The biological efficacy of the radiolabelled preparation was tested by recording serial gamma scintigraphic images after injecting the agent in both normal and arthritic knee joints of Wistar rats.

RESULTS

(177)Lu-hydroxyapatite was prepared with high yield and high radiochemical purity (approximately 99%) and the radiolabelled particles showed excellent in-vitro stability at room temperature. Serial scintigraphic images of normal and arthritic Wistar rats showed complete retention of activity within the synovial cavity, with no measurable activity leaching out from the joint until 168 h post-injection.

CONCLUSION

Studies with (177)Lu-hydroxyapatite indicate its potential for use as an agent for radiation synovectomy of digital joints, as a viable alternative to (169)Er-based agents. The results also demonstrate the possibility of preparing a large number of patient doses of (177)Lu-hydroxyapatite from indigenously produced (177)Lu using a natural target.

Comparison of extraarticular leakage values of radiopharmaceuticals used for radionuclide synovectomy

OBJECTIVES

Radionuclide synovectomy is a reliable therapy in patients with chronic synovitis. However, radiation doses delivered to non-target organ systems due to leakage of radioactive material from the articular cavity are an important disadvantage of this procedure. In this study we compared extraarticular leakage values of the 3 commonly used radiopharmaceuticals; 90Y-citrate, 90Y-silicate and 186Re-sulfide colloid.

MATERIALS AND METHODS

Thirty-five patients with persistent synovitis were enrolled in the study. Twenty-two hemophilic, 8 rheumatoid arthritis and 5 patients with pigmented villonodular synovitis were studied. 90Y labeled silicate and citrate were used for knee joints and 186Re-sulfide for intermediate sized joints. Radiocolloid leakage values were evaluated using a gamma camera with 20% window centered over the bremsstrahlung photopeak of 90Y and a respective window over the 137 keV photopeak of 186Re. Regions of interest were drawn over the injection site, the regional lymph nodes and the background areas. Leakage of radiocolloid was calculated by dividing the counts/pixel in the regional lymph node area to the counts/pixel in the injection site.

RESULTS

No visible leakage was observed. The median leakage values calculated for 90Y-citrate, 90Y-silicate and 186Re-sulfide were found as 1.9%, 2.4% and 2.7%, respectively. The difference between the variability of leakage values was not statistically significant (p > 0.05).

CONCLUSION

There was no significant difference in terms of extraarticular leakage between 9Y-citrate, 9Y-silicate and 186Re-sulfide radiocolloids.

175Yb-labeled hydroxyapatite: a potential agent for use in radiation synovectomy of small joints

The preparation of 175Yb-labeled hydroxyapatite (HA) particle is described for possible use as an agent for radiation synovectomy (RS) of small-sized joints. 175Yb was produced by thermal neutron irradiation of enriched (98.6% in 174Yb) ytterbium target at a flux of approximately 3 x 10(13) n/cm(2)/s for 7 days. Specific activity of 5.5-6.0 GBq/mg and a very high radionuclidic purity to the extent of approximately 100% were obtained. In the work reported herein, HA could be labeled with 175Yb in very high radiochemical purity (>99%) using 10 mg of HA particle at pH approximately 7. The radiolabeled particulates showed excellent in vitro stability at room temperature. Serial scintigraphic images of normal as well as arthritis-bearing Wistar rats following intra-articular injection of 175Yb-HA particles in the knee joint showed complete retention of activity within the synovial cavity with no measurable activity leaching out from the joint till 144 h post-injection.

Stability of radioactive colloids for radiation synovectomy: influence of X-ray contrast agents, anaesthetics and glucocorticoids in vitro

AIM

This in-vitro study investigated the influence of the contrast agents iothalamate (Conray) and special preparations of iotrolan (Isovist) and iopromide (Ultravist) without ethylenediaminetetraacetic acid (EDTA), the anaesthetic Scandicain and the glucocorticoid triamcinolone on the stability of 90Y-, 169Er- and 186Re-radiocolloids used for radiation synovectomy.

METHODS

Vials of 1 ml of synovial fluid and 0.02 ml of radiocolloid suspension (0.56-3.6 MBq) were mixed with 0.06, 0.6 and 1.0 ml of each contrast agent. In an additional series, 0.1 ml of Scandicain and 0.1 ml of triamcinolone were tested. Thin layer chromatography and ultrafiltration/centrifugation were performed between 1 h and 15 days after incubation with negative and positive controls.

RESULTS

Within 24 h, 0.6 and 1.0 ml of Conray had mobilized 5-20% of the 90Y and 169Er out of the colloids. No interference between 186Re-colloids and Conray was visible before the ninth day after incubation. Iotrolan and iopromide without EDTA had no effect on the stability at shorter incubation periods of up to 6 days. The addition of Scandicain did not produce low-molecular 90Y or 169Er in the presence of synovial fluid. The fraction of low-molecular 186Re reached 4% after 24 h. Triamcinolone did not have any effect on stability in the presence of synovial fluid.

CONCLUSION

The disintegration of the radioactive colloids can be attributed to either the formation of EDTA complexes or radiolytic effects. The volume of the injected contrast agent should be as small as possible to confirm correct intra-articular distribution.

Radiosynovectomy in Hemophilic Synovitis: Correlation of Therapeutic Response and Blood-Pool Changes

AIM

The aim of this study was to evaluate the efficacy of 90Y and 186Re radiosynovectomy in patients with hemophilic synovitis.

METHODS

Radiosynovectomy was performed in 32 joints of 20 patients with hemophilic synovitis by using 90Y citrate colloid in the knee and 186Re sulfide colloid in the elbow, shoulder, and ankle. The indication for radiosynovectomy was the continuous presence of intra-articular blood or effusion and three or more hemorrhages into the same joint within the last 6 months. Response to therapy was first assessed at the 4th month with blood-pool imaging. Patients were followed up by clinical evaluation based on assessments of joint-bleeding frequency, using range of motion measurements at 6-month intervals for an average of 1 year (range, 9-15 months).

RESULTS

A marked decrease (an 80%-100% decrease) in bleeding episodes was seen in 24 of 32 (75%) joints, a moderate decrease (51%-79% decrease) in 1 (9%) joint, and a mild decrease (30%-50%) in 3 (13%) joints. Frequency of intra-articular bleeding after treatment was unchanged in only 13% of the joints. The number of hemarthroses significantly decreased after therapy (p < 0.05). The mean bleeding frequency of the joints were 1.7 +/- 0.9 and 0.3 +/- 0.7 per month before and after therapy, respectively. The ratios of joints which had marked improvement after therapy were 86% in the ankle, 73% in the elbow, and 58% in the knee. There was no significant difference between percent joint range of motion limitations measured before and after therapy (p > 0.05). The correlation between therapeutic outcome (in terms of joint bleeding) and the difference of pre- and posttherapeutic blood-pool indices were significant (r = 0.594; p < 0.05), while the correlation between therapeutic outcome and pretherapeutic radiologic scale and pretherapeutic blood-pool indices were not significant (r = 0.095; p > 0.05; r = -0.089; p > 0.05, respectively).

CONCLUSION

Radiosynovectomy is a simple but quite effective and efficient procedure in limiting the frequency of joint hemorrhage in patients with hemophilia. Blood-pool imaging may be an objective means for monitoring therapy response in these patients.

Scintigraphy in rheumatic diseases

The aim of this review is to summarise the clinical role of nuclear medicine in rheumatology taking into consideration the most specific diagnostic applications and other worthwhile therapeutic contributions. Traditional bone scintigraphy and recent inflammation-targeting radiopharmaceuticals, such as radiolabelled leucocytes and immunoscintigraphy, now allow us to obtain highly sensitive total-body and tomographical imaging information that can be used for the diagnosis of osteoarticular disease. The most common extra-articular manifestations of rheumatic diseases due to digestive, central nervous, respiratory and cardiovascular system involvement can be diagnosed by specific scintigraphic methods. Radiosynovectomy plays an important role in providing effective treatment for some joint diseases that are resistant to pharmacological therapy. Diagnostic and therapeutic applications of nuclear medicine show the highest efficacy in the early phase of rheumatic diseases. In more advanced stages, scintigraphical techniques play a complementary role to radiographical investigations in the assessment of prognosis and therapy efficacy.

Is corticosteroid coinjection necessary for radiosynoviorthesis of patients with hemophilia?

PURPOSE

Radiation synovectomy is frequently combined with intraarticular corticosteroid injection in the treatment of rheumatoid arthritis to reduce local inflammation and lymphatic clearance of radiocolloid. However, this practice is not universally accepted because corticosteroids have local and systemic toxicity such as osteonecrosis and cartilage damage and whether simultaneous corticosteroid injection together with radiocolloids is necessary in other forms of chronic synovitis like patients with hemophilia remains to be determined.

MATERIALS AND METHODS

In this study, we performed radiosynoviorthesis in 14 joints of 12 patients with hemophilia with chronic knee synovitis without corticosteroid coadministration and measured radiocolloid leakage from the joint space. Five mCi Y-90 radiocolloid was injected under local anesthesia and the needle was flushed with additional lidocaine injection instead of corticosteroid. The joint was then manipulated through a full range of extension and flexion to distribute the particles homogeneously throughout the joint space. The joint was then splinted for 48 hours to minimize leakage from the joint space. After the immobilization period, radiocolloid leakage was evaluated using a gamma camera with a 20% window centered over the maximum Bremsstrahlung photopeak of Y-90. Regions of interest were drawn to the injection site on the knee joint and to the ipsilateral inguinal lymph node area. Leakage of radiocolloid was calculated by dividing the background-corrected counts/pixel at the inguinal region by the counts/pixel at the injection site.

RESULTS

One of 12 patients who had knee arthroplasty was previously found to have a high amount of leakage. In this patient, 70% of radiocolloid at the injection site drained into the pelvic lymph nodes. In the remaining 11 patients, no lymph nodes were visualized in the groin area and the measured average leakage for these patients was 2.3% (range, 0-13).

CONCLUSION

We concluded that in cases of appropriate particle size and strict immobilization of knee joints, leakage of radiocolloid was minimal and steroid coinjection might not be necessary for radiosynoviorthesis of patients with hemophilia with chronic knee synovitis.

Characterization of the ideal candidate for knee radiosynoviorthesis treatment in patients with rheumatoid arthritis

OBJECTIVES

(1). To identify the main parameters that positively influence the outcome of knee radiosynoviorthesis (RSO) in patients with rheumatoid arthritis (RA) and (2). to determine the ideal candidate for this procedure.

METHODS

We considered 80 knees (in 57 patients) that had undergone follow-up for at least 5 years and/or prosthesis implantation after RSO treatment. The parameters evaluated included age, gender, oligo-articular or polyarticular involvement, disease progression, radiological joint damage (Larsen scale), instability and/or axial deviation, body mass index (BMI), and psychological motivation for prosthesis implantation.

RESULTS

Knee Larsen stage IV, presence of instability-axial deviation, disease progression, psychological motivation to the surgical replacement and BMI higher than the 85th percentile were associated with a negative outcome for RSO (prosthesis implantation).

CONCLUSIONS

The ideal candidate for the RSO treatment is a patient with a low Larsen stage, no instability and/or axial deviation and a BMI below the 85th percentile. A patient's psychological motivation for the treatment should be evaluated before the RSO procedure.

Advances in radionuclide therapeutics in orthopaedics

Radiopharmaceuticals not only are used for diagnostic purposes but also increasingly in the treatment of many orthopaedic-related disorders. With the development of specific bone-seeking radiopharmaceuticals, the side effects of treatment are minimized, therapeutic effects are sustained, and concomitant use with other modalities may have synergistic effects. These new radiopharmaceuticals, such as strontium 89 and samarium 153-ethylene diamine tetramethylene phosphate, have been used as palliative treatment for patients with bone pain from osseous metastases. Excellent clinical responses with acceptable hematologic toxicity have been observed, and clinical results rival those of external beam radiation therapy. Radiosynovectomy has become a procedure of choice at many institutions to treat recurrent hemarthrosis and chronic synovitis in patients whose hemophilia is poorly controlled with medical management. Radiosynovectomy also remains a viable option to treat chronic synovitis secondary to inflammatory arthropathies, particularly rheumatoid arthritis.

Radionuclide synovectomy and chronic haemophilic synovitis in Asians: a retrospective study

Radionuclide synovectomy has been identified as the procedure of choice in treating chronic haemophilic synovitis among Caucasian populations. Its effectiveness among East Asians has not been studied. A retrospective study was carried out on 12 Asian haemophiliacs who underwent 12 radionuclide synovectomies. The average follow-up was 30.7 months (range 6-55) for primary procedures. 32P chromic phosphate and 188Re-tin colloid were injected into target joints according to protocol. There was a significant 80% decrease in the median frequency of haemarthrosis from 1.4 per month (range 0.2-7.0) to 0.25 per month (range 0.0-1.8) (P<0.05). Half of the patients had excellent results by 1 year of synovectomy. The median factor usage for target joint haemarthrosis postsynovectomy was 792 units per month (range 0-3209) reduced significantly from a presynovectomy level of 1452 units per month (range 306-7125) (P<0.05). Patients also reported a reduction in joint pain scores, and an improvement in joint mobility and quality of life. The majority of patients were satisfied with the overall outcome of radionuclide synovectomy. Radionuclide synovectomy appears to be effective in reducing the incidence of target joint haemarthrosis and quantity of factor usage for such bleeds among Asians with haemophilic synovitis.

Radiation synovectomy with holmium-166 ferric hydroxide macroaggregate in equine metacarpophalangeal and metatarsophalangeal joints

OBJECTIVES

To evaluate the effects of radiation synovectomy (RSYN) with holmium-166 ferric hydroxide macroaggregate (Ho-166 FHMA) on synovium and synovial fluid in normal metacarpo- and metatarsophalangeal joints of horses and to determine intraarticular distribution of radioactivity after Ho-166 FHMA treatment.

STUDY DESIGN

Either Ho-166 FHMA or nonradioactive Ho-165 FHMA was injected into metacarpo- or metatarsophalangeal joints.

ANIMALS

Six adult mixed-breed horses without any clinical evidence of metacarpo- or metatarsophalangeal joint disease.

METHODS

Joints were injected with a single high dose of Ho-166 FHMA (mean, 1,000 MBq/joint) or a nonradioactive Ho-165 FHMA preparation (controls). Clinical examination, arthroscopy, synovial fluid analyses, and histologic studies were performed to detect effects of RSYN. Scintigraphy was used to localize intraarticular distribution of Ho-166 FHMA.

RESULTS

Ho-166 FHMA treatment induced joint inflammation leading to regional edema, effusion, and scar tissue formation. Scintigraphy revealed the highest intensity of radioactivity in the proximal plantar joint pouch, at which the Ho-166 FHMA treatment caused multifocal necrosis. In the dorsal joint pouch, however, arthroscopic study and histologic analysis showed very little effect of RSYN. There was no regeneration of synovium evident within 2 months. Synovial fluid protein concentration was significantly (P <.01) elevated, and some residual radioactivity remained for 5 days after Ho-166 FHMA injection.

CONCLUSIONS

Injection of a single high dose of Ho-166 FHMA caused multifocal necrosis of synovium and deep, soft-tissue injury in equine fetlock joints.

CLINICAL RELEVANCE

Inflamed equine joints with synovial lining hyperplasia could benefit from Ho-166 FHMA-induced radiation synovectomy if excessive scar tissue formation can be avoided.

188Re-tin-colloid as a new therapeutic agent for rheumatoid arthritis

Radiation synovectomy is a useful treatment modality in patients with refractory synovitis. We have developed a 188Re-tin-colloid as a new radiopharmaceutical agent and investigated its efficacy and safety in patients with rheumatoid arthritis. Radiation synovectomy was performed using 188Re-tin-colloid in 22 knees from 21 rheumatoid arthritis patients refractory to intra-articular corticosteroid injection. The efficacy and safety of administration of 370-1110 MBq of 188Re-tin-colloid were evaluated after 1, 3, 6, 9 and 12 months. Pain intensity on a visual analogue scale decreased significantly 12 months after therapy (mean+/-SD: 68.0+/-26.1 mm vs. 25.1+/-23.4 mm; P=0.0001 by the paired t-test). Pain decreased in 19 cases (86.3%), joint tenderness improved in 14 cases (63.6%) and joint swelling was reduced in all cases (100%). 188Re-tin-colloid was safe. The residual activity of 188Re in the blood was 0.077%+/-0.25% of the injected dose. The radioactivity of 188Re in the urine was 0.14%+/-0.13% of the injected dose. Transient reactive synovitis was observed in 18 cases (81.8%). No clinical side-effects or abnormalities in leucocyte count, platelet count, liver function tests or urine analysis were observed in any patient. In conclusion, in this first study of radiation synovectomy using 188Re-tin-colloid for patients with rheumatoid arthritis, the treatment resulted in the improvement of arthritis and was well tolerated.

Comparison of Tc-99m HIG and three-phase Tc-99m MDP bone scintigraphy for evaluating the efficacy of Yttrium-90 silicate radionuclide synovectomy

PURPOSE

The aim of this study was to compare Tc-99m human immunoglobulin (HIG) and three-phase Tc-99m MDP bone scintigraphy for the assessment of the efficacy of Y-90 silicate therapy in rheumatoid knee synovitis.

MATERIALS AND METHODS

Fifteen patients with rheumatoid arthritis and chronic persistent synovitis in 23 knee joints had radionuclide synovectomy with Y-90 silicate. The patients underwent imaging before and 3, 6, 9, and 12 months after therapy using clinical evaluation, Tc-99m HIG scintigraphy, and three-phase Tc-99m MDP bone scintigraphy.

RESULTS

In the 13 of 23 knee joints that showed successful clinical results with Y-90 therapy, the Tc-99m HIG index values obtained 3 months after radionuclide synovectomy were significantly lower than the pretreatment index values (P < 0.001). In the same 13 joints, the Tc-99m MDP index values (in the blood-pool and delayed phases) before and 3 months after therapy were statistically similar. Six months after injection, these values were significantly lower in both the blood-pool (P < 0.001) and late (P < 0.05) phases in all 13 joints. In the other 10 of 23 knee joints that did not respond to treatment, the Tc-99m MDP and Tc-99m HIG index values were statistically similar before and after Y-90 therapy.

CONCLUSIONS

Based on these findings, Tc-99m HIG scintigraphy appears to be a valuable method that complements clinical assessment of the efficacy of Y-90 silicate therapy in rheumatoid knee synovitis, starting in the early post-treatment period. However, three-phase Tc-99m MDP bone scintigraphy may be valuable in the late postsynovectomy period.

Analysis of lapine cartilage matrix after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate

OBJECTIVE

To study the short and long term effects of radiosynovectomy on articular cartilage in growing and mature rabbits.

METHODS

The articular cartilage of the distal femurs of rabbits was examined four days, two months, and one year after radiosynovectomy with holmium-166 ferric hydroxide macroaggregate ([(166)Ho]FHMA). Arthritic changes were evaluated from histological sections by conventional and polarised light microscopy, and glycosaminoglycan measurements using safranin O staining, digital densitometry, and uronic acid determination. Proteoglycan synthesis was studied by metabolic [(35)]sulphate labelling followed by autoradiography, and electrophoretic analysis of extracted proteoglycans. Northern analyses were performed to determine the mRNA levels of type II collagen, aggrecan, and Sox9 in cartilage samples.

RESULTS

Radiosynovectomy had no major effect on the histological appearance of articular cartilage in mature rabbits, whereas more fibrillation was seen in [(166)Ho]FHMA radiosynovectomised knee joints of growing rabbits two months after treatment, but not after one year. Radiosynovectomy did not cause changes in the glycosaminoglycan content of cartilage or in the synthesis or chemical structure of proteoglycans. No radiosynovectomy related changes were seen in the mRNA levels of type II collagen, whereas a transient down regulation of aggrecan and Sox9 mRNA levels was seen in young rabbits two months after [(166)Ho]FHMA radiosynovectomy.

CONCLUSIONS

[(166)Ho]FHMA radiosynovectomy caused no obvious chondrocyte damage or osteoarthritic changes in mature rabbits, but in growing rabbits some transient radiation induced effects were seen--for example, mild cartilage fibrillation and down regulation of cartilage-specific genes.

[Quantification of bone scintigraphy as an objective method in the follow-up of radioisotopic synoviorthesis]

This work tries to provide the clinicians an objective tool that can contribute to the assessment of the results of radioisotopic synoviorthesis (RS). This study aims to assess the value of the quantification of bone scintigraphy in blood pool and late phase of the affected joints treated with 90Y silicate, in order to observe the clinical improvement experienced by most of these patients. A total of 69 bone scintigraphies (BS) in blood pool and late phase have been quantified. They belonged to 23 patients who were treated with RS with 90Y. The first scintigraphy study was performed before the treatment, the second and the third ones were performed 2 and 6 months after treatment. In each BS we quantified the index: counts per pixel of healthy / affected joint. We also have calculated the fraction in the late phase: counts per pixel of healthy bone / counts per pixel of affected and healthy joint. For the comparative statistical analysis of the results we used the Student's t test. We considered statistical significance when p < 0.05. All the patients presented clinical improvement. If we compare the index obtained in BS 2 months after treatment and pre-treatment we find statistical significance (p < 0.05) in the increase of index in the anterior view and late phase. If we compare the index obtained in BS 6 month after treatment and pre-treatment, we find a statistically significant increase in the anterior (p < 0.01) and posterior (p < 0.05) view of the blood pool phase and the anterior view of late phase (p < 0.01). The fraction counts per pixel of healthy bone / counts per pixel of affected and healthy joint did not present a significant increase in any BS control (2 and 6 months). We recommend quantification using the index (counts per pixel healthy / affected joint ) proposed in this work, because it is easy to perform, cheap and reliable in the follow-up of patients treated with RS.

Experimental radiation synovectomy in rabbit knee with holmium-166 ferric hydroxide macroaggregate

Holmium-166 ferric hydroxide macroaggregate (Ho-166 FHMA) particles possess two important properties for radiosynovectomy; relatively short half-life of the radioisotope and appropriate carrier size. Both these minimize radioactive leakage from the treated joint. This study was conducted to assess the effects of Ho-166 FHMA on synovium and synovial fluid in rabbit knee joints. Whole-knee autoradiography was utilized to determine distribution of radioactivity after intra-articular Ho-166 FHMA injection. Intra-articular injection of Ho-166 FHMA resulted in focal acute radiation necrosis in synovial lining but no hyperplasia of synoviocytes. Later, subsynovial fibrosis became evident. White blood cell and total protein levels in the joint fluid were elevated because of intra-articular inflammation due to the acute effects of radiation. Whole knee autoradiograms showed uneven distribution of the radionuclide along the synovium and extraarticular leakage on the third day after treatment.

Painful multifocal arthritis: therapy with rhenium 186 hydroxyethylidenediphosphonate ((186)Re HEDP) after failed treatment with medication--initial results of a prospective study

Eight patients (77 joints) with polyarthritis were treated systemically with 570 MBq (15.4 mCi) of rhenium 186 ((186)Re) hydroxyethylidenediphosphonate (HEDP). Pain and disease activity were assessed monthly. In six (75%) of eight patients, a single injection of (186)Re HEDP led to an improvement in disease activity. Systemic low-dose treatment with (186)Re HEDP can reduce pain and disease activity in patients with polyarthritis.

32P chromic phosphate radiosynovectomy for chronic haemophilic synovitis

The principal medical consequence of haemophilia is the development of arthropathy, initiated by a haemarthrosis giving rise to chronic synovitis. Traditional methods of synovectomy include open excision and arthroscopy each of which require substantial amounts of clotting factor concentrate for several weeks, and in the case of open synovectomy, is often associated with loss of range of motion and arthrofibrosis. Radiosynovectomy, the intra-articular injection of low penetration radiocolloids, has been utilized outside the United States for over 20 years. Since 1988, our centre has performed 170 radiosynovectomies utilizing 32P chromic phosphate (32P). This study reports results of 130 32P radiosyovectomies with an average follow-up of 36.5 months (6-140 months). For primary procedures, excellent and good results (haemarthrosis reduction from 75 to 100%) were obtained in 79.2% of cases at 6 months to 8 years. For repeat procedures a combination of excellent and good results were obtained in 62.4% of cases at 6 months to 3 years. Regression analysis showed no correlation between results and age or degree of arthropathy. Radiation was well contained within the joint. There were no observed or identified complications. The procedure is highly cost effective in comparison to open surgical or arthroscopic synovectomy.

Cost-Effectiveness of Prosorba Column Therapy for Rheumatoid Arthritis: A Framework for Analysis

Apheresis with the Prosorba column is safe and effective for treating refractory rheumatoid arthritis. It also is resource intensive. Economic evaluation of Prosorba column therapy could help promote efficient use of this technology. This article describes a framework and the data requirements for analyzing the cost-effectiveness of Prosorba column therapy. Several factors are considered in developing the framework including the target patient population, treatment alternatives, and clinical, economic, and quality of life outcomes of alternative treatments. We propose decision modeling as the appropriate study design because it provides a flexible framework for combining and analyzing data from different sources including experimental and nonexperimental studies. The cost-effectiveness of Prosorba column therapy will depend on the patient population in which it is used and the other treatment options still available to these patients. Offsets to the costs of providing Prosorba column therapy are likely to be largest in treatment-refractory patients and when this therapy is compared to other expensive new agents such as etanercept.

Long-term results of radiation synovectomy: a clinical follow-up study

Radiation synovectomy by intra-articular injection of beta-emitting radionuclides is a reliable and easy-to-perform therapy without harmful side effects for the treatment of inflammatory rheumatoid as well as degenerative joint diseases. The indication for radiation synovectomy is based on both clinical symptoms and on proven hyperperfusion, with active synovitis being seen on a pre-therapeutic three-phase bone scan. In this study, the clinical response after 6-18 months, evaluated by a standardized questionnaire, was compared with the reduction of synovitis seen on three-phase bone scintigraphy after treatment of 475 joints in 151 patients. The best clinical results were obtained in cases of true rheumatoid arthritis (73.4%), with less in other kinds of arthritis (48.8%) such as psoriatic or reactive arthritis. Because of the inflamed synovium being the main target tissue, clinical results in osteoarthritis with severe bone destruction are poorer (33.9%). However, synovitis can be markedly reduced (in approximately 70%), regardless of the underlying diagnosis, as shown by post-therapeutic three-phase bone scanning. Radiation synovectomy can be recommended in all kinds of arthritis. It should also be considered in cases of osteoarthritis as a last therapeutic option prior to joint replacement.