Monitoring of the biodistribution and biokinetics of dysprosium-165 ferric hydroxide with a shadow-shield whole-body counter

Radiation synovectomy is indicated when conventional pharmacological treatment of chronic synovitis has proved insufficient. In these cases dysprosium-165 ferric hydroxide (DFH) has been demonstrated to be clinically effective. After application of the agent, blood activity measurements and monitoring of activity distribution by gamma camera imaging over the local lymph nodes and the liver are commonly performed for control of possible leakage. In addition, we have used a shadow-shield whole-body counter with a profile facility to evaluate the biokinetics and biodistribution of¹⁶⁵Dy-DFH. Fifteen intra-articular injections were performed in 13 patients who received a median activity of 6.8 GBq (range 0.5-9.9 GBq)¹⁶⁵Dy-DFH. Activity profiles were obtained with the whole-body counter 2, 4 and 6 h after injection of¹⁶⁵Dy-DFH. The doses to non-target organs were calculated using the software MIRDOSE 3. In 10 of 15 treatments, absence of any leakage could be demonstrated. The effect of scattered rays could be observed in 14 measurements. In three patients small amounts of activity could be detected in the urinary bladder and in three patients activity was detected in the local inguinal lymph nodes, while no leakage could be detected by camera imaging. In these cases the individual doses to the bladder were 15 Gy, 65 mGy and 50 mGy, and those to the lymph nodes, 0.54 Gy, 0.89 Gy and 2.41 Gy. The whole-body counter also enabled the monitoring of activity profiles related to more complex pathological structures. In conclusion, using a whole-body counter activity leakage could be detected with much higher sensitivity than by using a gamma camera. The biodistribution of¹⁶⁵Dy-DFH could be determined, and leakage could be localised and related to organs. These results encourage the use of a whole-body counter to identify, the site and extent of activity leakage.     

Influence of radiation synovectomy on articular cartilage, synovial thickness and enhancement as evidenced by MRI in patients with chronic synovitis.

Radiation synovectomy is a safe and effective treatment for chronic synovitis that is refractory to the repetitive, intra-articular application of glucocorticosteroids in patients with rheumatoid or seronegative arthritis. Short-term and long-term effects of radiation synovectomy on articular cartilage, synovial enhancement and thickness were assessed in a prospective, clinical trial by MRI. METHODS: Thirteen patients (mean age 39+/-13 y) were treated with a median activity of 8.4 GBq 165Dy ferric hydroxide, a radionuclide with favorable physical properties and a well-documented clinical safety and efficacy profile. MRI was performed on a 1.5-T MR unit using a circular polarized knee coil. RESULTS: After a mean observation period of 13 mo, a marked reduction in synovial enhancement was observed in 10 patients. The mean reduction in baseline synovial thickness (mean 7.6+/-3.0 mm) was 24% (P = 0.03) at 1 wk and 42% (P = 0.01) about 1 y after treatment, respectively. Clinically, 9 of 13 patients (69%) exhibited persistent response to radiation synovectomy. The local clinical score, as defined by the reduction in pain, pannus, joint effusion and by the increase in the range of motion, improved significantly (P = 0.01), from a median of 7 (range 4-10) to a median of 2 (range 0-9). One year after treatment, changes in the local clinical score were related to the decrease in synovial enhancement in MRI (r = 0.7, P = 0.008, n = 12). There were no persistent adverse effects, nor was there evidence for any severe radiation-induced damage to the articular cartilage. On later follow-up images, the structure of the articular cartilage remained unaltered in all but 3 patients, who had new, superficial erosions most likely attributed to an active disease with persistence of inflammation. CONCLUSION: This study suggests that radiation synovectomy with 165Dy-ferric hydroxide is effective in terms of reducing chronic synovitis without causing detectable harm to the articular cartilage, as shown by MRI.     

Radiation doses from patients undergoing yttrium-90 silicate knee radiosynovectomy

The present study was undertaken because we could not find references related to the minimal radiation doses emitted from patients treated with (90)Y-silicate colloid ((90)Y-SC) for radiosynectomy (RS). Radiation doses from 16 patients treated with about 181+/-13 MBq (90)Y-SC for RS of knee synovitis were estimated by dose rate measurements performed within 10 min after the (90)Y-SC injection with a calibrated survey dose ratemeter at 0.5 m, 1 m and 2 m distances from the treated joint. The mean dose rate values from the patients after bg subtraction were 0.6+/-0.4 microSv/h at 0.5 m, 0.1+/-0.1 microSv/h at 1 m and 0.1 +/- 0.0 microSv/h at 2 m distance. Dose rates at a distance of 0.5 m were significantly correlated (P<0.02) with the patient's weight but not with the height or the injected activity. The assumed estimated maximum whole body doses from a treated patient were 55 microSv for persons living with the patient, 2.9-3.4 microSv for the nursing staff, 0.2-1.8 microSv for the therapist physician and 0.3-0.6 microSv for the technologist, involved in the whole procedure. The above values were lower than those published with the same methodology for alternative RS radiopharmaceuticals for knee synovitis like dysprosium-165 ferric hydroxide macroaggregate ((165)Dy-FHMA) or holmium-166 ((166)Ho-FHMA), as estimated with their typical injected activities. In conclusion our results demonstrate that in (90)Y-SC knee synovectomy, the whole body radiation doses to medical and non medical personnel were as expected well below the maximum annual dose limits for the public and professionals exposed to radiation.     

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.     

Clinical efficacy of radiation synovectomy in digital joint osteoarthritis

Purpose Radiation synovectomy was developed for local treatment of rheumatoid arthritis. In this study, the long-term efficacy of radiation synovectomy was retrospectively evaluated in patients with osteoarthritis (activated arthrosis) of the digital joints using an algofunctional score.Methods Fifty-three digital joints in 29 patients (mean age 64.8 years) were treated by intra-articular injection of ¹⁶⁹Er citrate. All joints were painful despite pharmacotherapy and showed an elevated blood pool pattern in a pretherapeutic three-phase bone scan, indicative for local synovitis. The patients were asked to classify their complaints with respect to different daily manual activities on a ten-step pain scale from 1 (total disability) to 10 (lack of any impairment) prior to and after treatment, with a mean follow-up of 41 months. Local signs of osteoarthritis such as joint swelling or pain were additionally evaluated and were scored from progression of complaints to excellent improvement based on patient self-evaluation.Results All patients reported a pronounced improvement in their manual activities. The mean total score of 4.73±0.58 for all activities prior to treatment increased significantly to 6.79±0.47 after radiation synovectomy (p<0.05). The best results were obtained in the thumb base joints, whereas distal interphalangeal joints were frequently resistant to therapy.Conclusion Radiation synovectomy is highly effective in digital joint osteoarthritis with concomitant local synovitis.     

Cutaneous radiation necrosis as a complication of yttrium-90 synovectomy

Radiation synovectomy is an effective method of treatment of chronic synovitis in patients with conditions such as rheumatoid arthritis, haemophilic synovitis and pigmented villonodular synovitis. This case demonstrates one of the potential complications of this procedure in a 46 year old man treated with bilateral radiation synovectomy for haemophilic synovitis. Cutaneous radiation necrosis is a known but rare complication of this procedure and this case is reported to demonstrate this known complication and to highlight that appropriate technique is required to avoid this.     

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.     

The influence of redox status on inter-individual variability in the response of human peripheral blood lymphocytes to ionizing radiation

Purpose: Ionizing radiation (IR) can act on atomic structures, producing damage to biomolecules. Earlier investigations evaluating individual radiosensitivity in vitro were focused on cytogenetic biomarkers (chromosomal aberrations – CA and micronuclei – MN). Since IR can also cause oxidative damage by producing reactive oxygen species, the main goal of this investigation was to establish the influence of redox status on CA and MN frequency in human peripheral blood lymphocytes.

Materials and methods: Blood samples from 56 healthy donors were irradiated at doses of 0, 0.75, 1.5 and 3?Gy and then analyzed cytogenetically and biochemically.

Results: The results showed inter-individual variability in all analyzed parameters, as well as dose-dependent increases in almost all of them. Correlation analysis indicated no association between CA, MN and oxidative stress parameters. However, findings for overall response (HRR) parameters showed that donors with lower values for parameters of antioxidant status had increased levels of cytogenetic damage and higher responses to irradiation and vice versa.

Conclusion: Besides well-established cytogenetic biomarkers of radiation exposure, our results indicated promising future use for biochemical oxidative status parameters in routine radiation protection practice, since together they can provide a complete radiation response profile in cases of continuous low-dose exposure, as well as in a radiation emergency.     

Radiation synovectomy revisited

Radiation synovectomy is a potential weapon in the therapeutic armamentarium of nuclear medicine. It is an attractive alternative to surgical or chemical synovectomy for the treatment of rheumatoid arthritis. In this article the clinical results obtained with radiation synovectomy from the 1950s through 1992 are summarized and reviewed. Even after taking into account the paucity of well-controlled trials and rigorous clinical follow-up, it is clear that radiation synovectomy is efficacious in controlling the symptoms of rheumatoid arthritis. However, the procedure is not widely used because of concerns about leakage of radioactivity from the treated joint, and the resulting high doses that can be delivered to nontarget organs. New approaches to the preparation of radiolabeled particles for use in radiation synovectomy promise to minimize this leakage and thus allow the full potential of this important radiotherapy to be realized. Correspondence to: K.F. Deutsch     

Hydroxylysine excretion does not indicate collagen damage with downhill running in young men

The purpose of this study was to determine whether urinary excretion of hydroxylysine (HO-Lys) is increased following prolonged, predominantly downhill running. Such an increase would be evidence of exercise-induced collagen damage. Each of ten young men performed a treadmill running test to determine VO2peak (an approximation of VO2max) followed by 60 min of intermittent running on -10% slope. Total urine excreted from 48 h pre-exercise to 96h post-exercise was collected in 8-h samples for measurement of HO-Lys. In addition, both urinary 3-methylhistidine (3-MeHis) excretion and serum creatine kinase (SCK) activity were measured as indicators of muscle tissue damage. In no sampling period was post-exercise HO-Lys excretion altered compared with pre-exercise (e.g., pre-exercise: 82.2 +/- 9.6 mumol.24 h-1, mean +/- SE; 51.0 +/- 3.7 mumol.g creatinine-1; post-exercise: 72.9 +/- 2.0 mumol.24 h-1; 47.0 +/- 1.5 mumol.g creatinine-1). SCK activity was increased (346%) 24 h post-exercise, but not immediately, 48 h, or 72 h post-exercise. 3-MeHis excretion was not altered following exercise. There were no strong associations between HO-Lys excretion and either of the markers of muscle damage. We concluded that no evidence of exercise-induced collagen damage was provided by urinary HO-Lys excretion.     

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.     

153 Sm-柠檬酸-羟基磷灰石滑膜切除术治疗类风湿关节炎膝关节积液

目的观察^153Sm-柠檬酸-羟基磷灰石（HA）滑膜切除术治疗类风湿关节炎（RA）持续性膝关节积液的疗效和安全性.方法常规抗风湿药物治疗无效的RA患者43例,共67个持续性积液的膝关节,行^153Sm-柠檬酸-HA滑膜切除术,观察其疗效和不良反应.结果注射后24 h 8例患者关节外放射性泄漏占注射总量的百分比均＜1%.随访至治疗后3、6、12、24和36个月,总有效率分别为65.7%、85.1%、77.6%、64.2%和56.7%.随访至36个月时,治疗有效的关节复发率为33.3%.治疗有效的关节表现为肿痛缓解,积液量减少,滑膜厚度减小,关节功能活动改善.不良反应主要为一过性关节肿痛加重.结论^153Sm-柠檬酸-HA滑膜切除术治疗RA持续性膝关节积液短期、中期疗效及安全性较好.     

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.     

Radiation synovectomy with (166)Ho-ferric hydroxide: a first experience.

Radiation synovectomy (RS) is indicated when conventional pharmacologic treatment of chronic synovitis has not relieved its symptoms. The use of radionuclides that are bound to ferric hydroxide (FH) particles has been shown to be effective and safe for this procedure. (166)Ho-FH macroaggregates offer promising properties for RS but there is a lack of clinical data. We investigated the efficacy and safety of (166)Ho-FH in a prospective clinical trial in patients suffering from chronic synovitis. METHODS: Twenty-four intraarticular injections were performed in 22 patients receiving a mean activity of 1.11 GBq (range, 0.77-1.24 GBq) (166)Ho-FH. Blood activity measurements and monitoring of activity distribution were performed by whole-body gamma-camera imaging for control of leakage 3 and 24 h after injection of (166)Ho-FH. The patients were evaluated clinically before RS, 1 wk and 1 mo after the treatment, and thereafter in 3-mo intervals by assessing joint effusion, pannus, local pain, range of motion, and the patient's satisfaction. RESULTS: In 18 of 24 treatments, no leakage to nontarget organs was visible, whereas small amounts of activity could be detected in the local inguinal lymph nodes in 6 patients and to the lungs and to the liver in 1 patient (<0.1%). In all cases leakage to the lymph nodes was <1%. Leakage to the blood was negligible. Clinically, 17 patients (71%) exhibited a complete or partial response. CONCLUSION: RS with (166)Ho-FH was safe and effective in patients with chronic synovitis of different origin. Controlled clinical trials are necessary to evaluate the therapeutic efficacy and safety compared with the treatment with other radionuclides and glucocorticosteroids.     

Polymeric microspheres for radionuclide synovectomy containing neutron-activated holmium-166.

Poly-L-lactic acid (PLA) microspheres containing neutron-activated 166Ho were investigated as potential agents for radionuclide synovectomy. Stable 165Ho, complexed to acetylacetone (AcAc), was incorporated into PLA spheres by the solvent evaporation technique. Spheres prepared with the optimal mean particle size of 7.2 microns (range 2-13 microns) containing 25.4% 165Ho-AcAc (9.1% 165Ho) were irradiated in a high neutron flux to produce 31.1-36.0 mCi 166Ho. In vitro human plasma studies showed that the irradiated spheres retained 99.0 +/- 0.01% of the 166Ho at 314 hr. In-vivo retention studies were conducted by administering irradiated PLA spheres with 257-591 microCi 166Ho into the joint space of normal rabbits (n = 6). Biodistribution analysis and gamma camera analysis showed 166Ho retention in the joint space after 120 hr of 97.7% +/- 0.8% and 98.2% +/- 2.4%, respectively, with no uptake by the lymph nodes. The ease with which the PLA spheres can be made in the optimal size range for later irradiation and their ability to retain the 166Ho make them attractive agents for radionuclide synovectomy.     

Dysprosium (165Dy) hydroxide macroaggregates for radiation synovectomy--animal studies

This paper reports the development of a new chemical formulation, Dy-HMA, to utilise the advantages of dysprosium 165 in radiation synovectomy of certain forms of arthritis. Dy-HMA is a sterile suspension of dysprosium hydroxide macroaggregates (approximately 6 mg Dy/ml) in saline with the majority of particles in the 3-5 microns range. The absence of ferric hydroxide and a higher concentration of dysprosium in the formulation offer advantages over dysprosium ferric hydroxide macroaggregates, Dy-165-FHMA. Biodistribution studies in rats and rabbits with Dy-HMA show less leakage than with Dy-FHMA and considerably less leakage than with yttrium silicate colloid. Rabbits treated with intra-articular injections of Dy-HMA equivalent to 10-30 times the typical clinical dose showed no signs of any toxic effects.     

A phase I/IIa study on intra-articular injection of holmium-166-chitosan complex for the treatment of knee synovitis of rheumatoid arthritis

Previous animal studies have established that the intra-articular injection of holmium-166-chitosan complex (DW-166HC) causes effective necrosis of the inflamed synovium with litle leakage of radioactivity from the injected joint. Based on these findings, we conducted a phase I/IIa study to examine the biodistribution of DW-166HC and to assess the safety of DW-166HC for the treatment of knee synovitis in patients with rheumatoid arthritis (RA). A total of 16 patients [1 man, 15 women; median age 49 (range 36-65) years] who had RA knee synovitis refractory to disease-modifying anti-rheumatic drug treatments of > 3 months' duration were randomly assigned to three treatment groups with different radiation doses of DW-166HC: 370 MBq (n = 6), 555 MBq (n = 5) and 740 MBq (n = 5). In each treatment group, blood and urine radioactivity were analysed by beta counter and biodistribution of the injected DW-166HC was evaluated using a gamma scan camera. Clinical assessment was done according to three variables (evaluation method): knee joint pain (visual analogue scale), range of motion (goniometry) and joint swelling (circumference of knee joint). The duration of follow-up observation was 3 months. Following the intra-articular injection of DW-166HC, the blood radioactivity was little changed from the baseline measurement and the accumulated radioactivity excreted in urine was minimal. Gamma scan study indicated that most of the injected radiochemical was localized within the injected joint cavity, and the extra-articular leakage was negligible at 24 h after the injection: brain, 0.3%; lung, 0.6%; abdomen, 0.7%; and pelvis, 0.8%. Major adverse events were transient post-injection knee joint pain and swelling. These results suggest that DW-166HC might be a safe agent for radiation synovectomy, particularly for the treatment of knee synovitis of RA, and further trials in a larger patient population are warranted to evaluate the therapeutic efficacy of DW-166HC.     

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.     

The results of 394 consecutive cases of knee joint radiation synovectomy (radiosynoviorthesis) using 90 Y

The aim of this study was to assess the treatment results of 90Y radiation synovectomy for chronic exudative synovitis of knee joints. The retrospective data consist of 394 consecutive knee radiation synovectomies performed using 6 mCi (222 MBq) of 90Y. The assessment included 3-point custom pain and joint mobility scale, evaluation of joint’s circumference, binary joint’s temperature evaluation, patellar ballottement test, indications for puncture and its volume in applicable cases. 21 cases had to be forfeited due to missing data regarding follow-up. The final analysis of 373 treatment procedures performed in 253 patients yielded following results—at 6 months after treatment, 80.9% of the patients reported at least partial pain relief (including 33.3% with complete pain relief), which increased to 86.7% at one year. The pain intensity decreased over time, however, the outcomes were worse in older patients. The probability of pain recurrence was 15% at 6 months, and 28% at one year. It was highest in post-traumatic synovitis, and lowest in pigmented villonodular synovitis. The circumference of the treated knee joints decreased over the course of follow-up, however, the decrease was significantly lower in older patients. The fraction of patients with full knee joint mobility increased from 34.6 to 40.6% at 6 months and 49.2% at one year. The percentage of patients that required articular puncture decreased from 62.8% at baseline to about 35.6% at 6 months, and 32.8% at one year. Positive patellar ballottement was found in 68.5% before treatment and remained at about 40–50% during the course of follow-up. The increased temperature of the joint was reported in 51.2% at baseline and decreased to 33% at 6 months and 28.3% at one year. (1) Radiation synovectomy is a safe and effective method of treatment in patients with exudative synovitis, however, the pain recurrence rate is significantly higher in post-traumatic exudative synovitis compared to pigmented villonodular, undifferentiated, and rheumatoid arthritis. (2) Our results suggest that older patients have worse treatment results with radiation synovectomy compared to younger patients.     

Rhenium-188 sulphur colloid as a radiation synovectomy agent

Radiation synovectomy has been shown to be an effective treatment for the rheumatoid arthritic knee. In this study, we evaluated the suitability of rhenium-188 as a radiation synovectomy agent. In addition, we were successful in labelling sulphur colloid with¹⁸⁸Re. In vitro stability tests revealed that more than 95% of the¹⁸⁸Re remained in colloid form over a 3-day period. Intra-articular injection of¹⁸⁸Re sulphur colloid into arthritic rabbit joints was followed by gamma camera imaging to quantify the leakage. The mean retention percentages of¹⁸⁸Re colloid in arthritic knees were 93.7% (±1.4%), 90.8% (±1.7%) and 87.2% (±0.6%) at 1 h, 1 day and 2 days, respectively. A biodistribution study of the arthritic rabbits revealed that the highest activity outside the knees was in the liver and the kidneys. Our preliminary results indicate that 188Re sulphur colloid may be an effective radiopharmaceutical for radiation synovectomy.