Radiosynovectomy in the therapeutic management of arthritis

The effect of radiation synovectomy with phosphorus-32 on the pain and swelling in 31 RA patients with resistant monoarthritis of the knee

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by symmetric polyarthritis. RA is routinely treated by various systemic drugs; on the other hand, administration of intra-articular corticosteroids or different types of synovectomies can be used in case of systemic medication's failure. Chemical, radio isotopic, and surgical synovectomies are being used as therapeutic options for chronic synovitis to improve joint function. Chemical synovectomy is not well tolerated, and the long-term response is relatively low. Surgical synovectomy has a better success rate, but it recommends higher expenses. In radiation synovectomy, radioactive labeled particles are applied directly in the articular cavity, followed by homogeneous distribution in joint. Next, the radioactive particles are transported in the depth of synovia and phagocytized by inflammatory cells. Finally, the radiation leads to fibrosis and sclerosis of formerly inflamed synovial membrane; thus, it stops the inflammation and reduces the symptoms. It has a success rate of 40-100% and its effect can be similar to surgical synovectomy.

MATERIALS AND METHODS

Thirty-one patients with resistant monoarthritis of the knee were enrolled in this study. One millicurie of phosphorus-32 was injected into patients' knee via US guide. Saline was injected afterwards to prevent leakage. Direct pressure was performed after removing the needle and the knee was flexed slowly to ensure homogenous distribution and fixed with a splint for 1 to 2 weeks. Patients were followed up after 2 weeks, 1 month, 2 months, and 6 months. The following variables were assessed by the treating rheumatologist: patients' pain, joint tenderness, effusion, and ROM. At the time of injection and after the first week, patients were investigated for any complication including infection, necrosis, pain, and swelling. The effect of clinical characteristics and demographic data on existing complications and the changes of pain, joint tenderness, effusion, and ROM was assessed.

RESULTS

Thirty-one patients with the mean age of 54.5 ± 12.2 years and the mean disease duration of 12 ± 6.5 years were enrolled in this study. Mean DAS-28 ESR score for our patients was 4 ± 0.7. The pain, effusion, and reduced ROM were decreased significantly after all follow-up intervals. Knee tenderness was not affected in the first 2 weeks, but it was reduced significantly after 1, 2, and 6 months. No serious complications like infection and necrosis were reported through our study. 51.6% and 54.8% of our patients reported pain and swelling in the administration site. Furthermore, 19.4% and 16.1% of patients reported deterioration of pain and effusion in the first week of injection.

CONCLUSION

In our study, we demonstrated that pain, tenderness, effusion, and ROM are improved after radiation synovectomy with phosphorus-32. We also showed that there was no serious adverse effect like infection and necrosis. However, more than half of our patients experienced pain and swelling of injection site at the time of administration. Key points • We demonstrated the efficacy of radiation synovectomy as a medication for monoarthritis. • The results of our study can lead to a bigger clinical trial to assess the benefits and adverse effects of radiation synovectomy in comparison to treatment with local or systemic corticosteroids.

A Novel Activatable Nanoradiosensitizer for Second Near-Infrared Fluorescence Imaging-Guided Safe-Dose Synergetic Chemo-Radiotherapy of Rheumatoid Arthritis

The precise theranostics of rheumatoid arthritis (RA) remains a formidable challenge in clinical practice. Exploring novel applications of contemporary therapeutic approaches like chemo-radiotherapy is promising as a highly effective strategy for RA. Herein, a novel activatable nanoradiosensitizer-40 (denoted as IRnR-40) is developed, based on encapsulating the clinically approved drugs cisplatin (DDP) and indocyanine green (ICG) within a gelatin shell to achieve second near-infrared fluorescence (NIR-II FL) imaging-guided safe-dose synergetic chemo-radiotherapy. The high concentration of matrix metalloproteinase-9 (MMP-9) in the RA microenvironment plays a pivotal role in triggering the responsive degradation of IRnR-40, leading to the rapid release of functional molecules DDP and ICG. The released ICG serves the dual purpose of illuminating the inflamed joints to facilitate accurate target volume delineation for guiding radiotherapy, as well as acting as a real-time reporter for quantifying the release of DDP to monitor efficacy. Meanwhile, the released DDP achieves highly effective synergistic chemotherapy and radiosensitization for RA via the dual reactive oxygen species (ROS)-mediated mitochondrial apoptotic pathway. To sum up, this activatable nanoradiosensitizer IRnR-40 is believed to be the first attempt to achieve efficient NIR-II FL imaging-guided safe-dose chemo-radiotherapy for RA, which provides a new paradigm for precise theranostics of refractory benign diseases.

Formulation and In-vivo Characterization of 177Lu-tin-colloid as a Radiosynovectomy Agent

INTRODUCTION

Arthritis is an inflammatory disorder that affects one or more joints of the body for various reasons, including autoimmune disorders, trauma, or infection. In many cases, traditional long-term treatment with various drug combinations (NSAIDs, diseasemodifying antirheumatic drugs, systemic corticosteroids, etc.) can provide relief, but many joints require additional local treatment. Radiosynovectomy (RSV) is an alternative method to current treatment options. Both the global supply shortage of 90Y in recent years and the increasing use of 177Lu-labeled radiopharmaceuticals in the field of nuclear medicine have made it possible to develop 177Lu-labeled microparticles and test them in small groups as RSV agents. This study aimed to develop the 177Lu labeled tin colloid formulation and demonstrate its invivo characterization.

MATERIALS AND METHODS

Particle size, shape, and labelling efficiency of the four formulations developed were determined. The formula with the highest labelling efficiency was selected for further studies. The quality of the formulation was evaluated based on radionuclidic, radiochemical, and microbial purity. In-vitro stability was evaluated by determining the labelling efficiency. In-vitro stability was tested in PBS and synovial fluid. The biological characterization was assessed using SPECT/CT after injecting the formulation into the normal knee joints of the rabbits.

RESULTS

Aggregated colloidal particles were spherical with a particle size of <5 μm. Labelling efficiency and radiochemical purity were >95 and 97.65% (Rf=0.2), respectively. The formulation was stable in vitro for up to 72 hours, both in PBS and synovial fluid. The formulation was homogeneously distributed in the joint at 0 and 1 hour after injection, and radioactivity- related involvement and inguinal lymph node involvement due to possible leakage were not detected in the late period. No pyrogenic/allergic side effects were observed during this period.

CONCLUSION

177Lu-tin-colloid was successfully prepared under optimized reaction conditions with high binding efficiency and radiochemical purity. The radiolabeled colloid was found to be stable in-vitro both in PBS and synovial fluid at room temperature. Serial PCET/CT images revealed that the activity was completely retained within the synovial cavity, with no activity leakage out of the joint until 48 hours after the injection. With the support of the results from further clinical studies, it may be possible for the formulation to enter clinical use.

[Pain reduction by radiosynoviorthesis in rheumatism-induced synovitis of the elbow : Results of a retrospective multicenter data analysis]

BACKGROUND

Radiosynoviorthesis (RSO) is a nuclear medical local treatment modality for inflammatory joint diseases. It is indicated in patients with rheumatoid arthritis (RA) in joints with persistent synovitis despite adequate pharmacotherapy. Arthritis of the elbow joint occurs in up to 2/3 of patients with RA. Intra-articular radiotherapy using the beta emitter [186Re] rhenium sulfide leads to sclerosis of the inflamed synovial membrane with subsequent pain alleviation. The clinical efficacy in cubital arthritis, however, has so far only been described in small monocentric studies.

OBJECTIVE

The degree of pain alleviation by RSO was analyzed in patients with rheumatoid cubital arthritis, treated in several nuclear medical practices specialized in RSO.

MATERIAL AND METHODS

The subjective pain intensity before and after RSO was documented in a total of 107 patients with rheumatic cubital arthritis using a 10-step numeric rating scale (NRS). A difference of ≥ -2 is rated as a significant improvement. Follow-up examinations were done after a mean interval of 14 months after RSO (at least 3 months, maximum 50 months).

RESULTS

The mean NRS value was 7.3 ± 2.1 before RSO and 2.8 ± 2.2 after RSO. A significant pain alleviation was seen in 78.5% of all patients treated. The subgroup analysis also showed a significant improvement in the pain symptoms in all groups depending on the time interval between the RSO and the control examination. A significant pain progression was not observed. The degree of pain relief was independent of the time of follow-up.

CONCLUSION

Using RSO for local treatment of rheumatoid cubital arthritis leads to a significant and long-lasting pain relief in more than ¾ of the treated patients.

Radiosynovectomy for the Treatment of Chronic Hemophilic Synovitis: An Old Technique, but Still Very Effective

A radiosynovectomy (RS) should be indicated when recurrent articular bleeds related to chronic hemophilia synovitis (CHS) exist, established by clinical examination, and confirmed by imaging techniques that cannot be constrained with hematological prophylaxis. RS can be performed at any point in life, mainly in adolescents (>13−14 years) and adults. Intraarticular injection (IAI) of a radioactive material in children might be arduous since we need child collaboration which might include general anesthesia. RS is our initial option for management of CHS. For the knee joint we prescribe Yttrium-90, while for the elbow and ankle we prescribe Rhenium-186 (1 to 3 IAIs every 6 months). The procedure is greatly cost efficient when compared to surgical synovectomy. Chemical synovectomy with rifampicin has been reported to be efficacious, inexpensive, simple, and especially practical in developing countries where radioactive materials are not easily available. Rifampicin seems to be more efficacious when it is utilized in small joints (elbows and ankles), than when utilized in bigger ones (knees). When RS and/or chemical synovectomy fail, arthroscopic synovectomy (or open synovectomy in some cases) should be indicated. For us, surgery must be performed after the failure of 3 RSs with 6-month interims. RS is an effective and minimally invasive intervention for treatment of repeated articular bleeds due to CHS. Although it has been published that the risk of cancer does not increase, and that the amount of radioactive material used in RS is insignificant, the issue of chromosomal and/or deoxyribonucleic acid (DNA) changes remains a concern and continued surveillance is critical. As child and adulthood prophylaxis becomes more global, RS might become obsolete in the long-term.

Radiosynoviorthesis: almost seventy years of experience but still somewhat fameless

Radiosynoviorthesis (RSO) or radiation synovectomy has been practiced for more than half a century, but in many parts of the world, it is still relatively unknown and not used to its full potential in the standard care for chronic, persistent or recurrent synovitis. The working mechanism of RSO is simple yet elegant. Radiopharmaceutical particles are, after injection in the affected synovial joint, gobbled up by phagocytizing subsynovial inflammatory cells. As a consequence, the synovium will be irradiated locally resulting in synovial cell necrosis and inhibition of cell proliferation, which eventually leads to a decrease in the inflammatory response in the joint cavity. In this review RSO is once again brought to the attention and common indications for RSO are discussed. Also, appropriate activities of the administrated radiopharmaceuticals and coadministrated glucocorticoids are provided. Furthermore, a detailed database-assisted chronological overview of published literature of RSO in inflammatory and non-inflammatory diseases, like rheumatoid arthritis, psoriatic arthritis, osteoarthritis and osteochrondomatosis, hemophilic hemarthrosis and pigmented villonodular synovitis (PVNS) is provided. Based upon the published literature an indication of level of evidence of RSO is discussed. There is evidence that RSO is effective in persistent synovitis in patients with a variety of causes for synovitis, although the effectiveness seems to decrease over time. In these patients, RSO may not be used to its full potential in many parts of the world. Results in of RSO in hemophilia patients with hemarthrosis are favourable, however the evidence for the effectiveness of RSO in these patients is less firm and mainly based on case series. The evidence for the efficacy of RSO as adjuvant therapy in PVNS is, at best, of very low quality.

Outcomes of arthroscopic management for pigmented villonodular synovitis of the hip

INTRODUCTION

Early synovectomy is considered as the main treatment of pigmented villonodular synovitis (PVNS) of the hip in young patients with preserved cartilage. The purpose of the study is to evaluate outcomes of arthroscopic management for PVNS of the hip.

METHODS

Patients who underwent primary hip arthroscopy for the treatment of histology-confirmed PVNS by the senior author between January 2012 and December 2016 were retrospectively reviewed. We excluded patients who had less than 1-year follow-up or had undergone primary surgeries with other surgeons and then received revision hip arthroscopic procedures by the senior author. The recurrence of PVNS and postoperative condition of affected hip were assessed by follow-up magnetic resonance imaging (MRI). Patient-reported outcomes of modified Harris hip score (mHHS) and 12-item International Hip Outcome Tool (iHOT-12) were collected at latest follow-up.

RESULTS

Nine patients (2 males, 7 females) with a mean age of 24.3 ± 11.2 years (range 14-44 years) were included in this study. Localized PVNS was observed in four patients, and diffuse PVNS was observed in five patients. No patient presented with advanced osteochondral destruction. Five patients received single adjuvant radiosynoviorthesis. No patient had evidence of recurrence based on follow-up MRI. Patient-reported outcomes were obtained in eight patients at mean 55.8 ± 26.1 months (range 24-84 months) after the index surgery. The mean mHHS was 94.6 ± 4.9 (range 84.7-100) and the mean iHOT-12 was 93.3 ± 20.2 (range 50-120). No patient needed secondary surgery during the follow-up period.

CONCLUSION

Arthroscopic subtotal synovectomy can offer favorable short to mid-term outcomes in the treatment of hip PVNS in case of no advanced osteochondral damage at presentation.

Cutting edge rare earth radiometals: prospects for cancer theranostics

Background

With recent advances in novel approaches to cancer therapy and imaging, the application of theranostic techniques in personalised medicine has emerged as a very promising avenue of research inquiry in recent years. Interest has been directed towards the theranostic potential of Rare Earth radiometals due to their closely related chemical properties which allow for their facile and interchangeable incorporation into identical bifunctional chelators or targeting biomolecules for use in a diverse range of cancer imaging and therapeutic applications without additional modification, i.e. a “one-size-fits-all” approach. This review will focus on recent progress and innovations in the area of Rare Earth radionuclides for theranostic applications by providing a detailed snapshot of their current state of production by means of nuclear reactions, subsequent promising theranostic capabilities in the clinic, as well as a discussion of factors that have impacted upon their progress through the theranostic drug development pipeline.

Main body

In light of this interest, a great deal of research has also been focussed towards certain under-utilised Rare Earth radionuclides with diverse and favourable decay characteristics which span the broad spectrum of most cancer imaging and therapeutic applications, with potential nuclides suitable for α-therapy (¹⁴⁹Tb), β⁻-therapy (⁴⁷Sc, ¹⁶¹Tb, ¹⁶⁶Ho, ¹⁵³Sm, ¹⁶⁹Er, ¹⁴⁹Pm, ¹⁴³Pr, ¹⁷⁰Tm), Auger electron (AE) therapy (¹⁶¹Tb, ¹³⁵La, ¹⁶⁵Er), positron emission tomography (⁴³Sc, ⁴⁴Sc, ¹⁴⁹Tb, ¹⁵²Tb, ¹³²La, ¹³³La), and single photon emission computed tomography (⁴⁷Sc, ¹⁵⁵Tb, ¹⁵²Tb, ¹⁶¹Tb, ¹⁶⁶Ho, ¹⁵³Sm, ¹⁴⁹Pm, ¹⁷⁰Tm). For a number of the aforementioned radionuclides, their progression from ‘bench to bedside’ has been hamstrung by lack of availability due to production and purification methods requiring further optimisation.

Conclusions

In order to exploit the potential of these radionuclides, reliable and economical production and purification methods that provide the desired radionuclides in high yield and purity are required. With more reactors around the world being decommissioned in future, solutions to radionuclide production issues will likely be found in a greater focus on linear accelerator and cyclotron infrastructure and production methods, as well as mass separation methods. Recent progress towards the optimisation of these and other radionuclide production and purification methods has increased the feasibility of utilising Rare Earth radiometals in both preclinical and clinical settings, thereby placing them at the forefront of radiometals research for cancer theranostics.

A review of advances in the last decade on targeted cancer therapy using 177Lu: focusing on 177Lu produced by the direct neutron activation route

Lutetium-177 [T½ = 6.76 d; Eβ (max) = 0.497 MeV; maximum tissue range ~2.5 mm; 208 keV γ-ray] is one of the most important theranostic radioisotope used for the management of various oncological and non-oncological disorders. The present review chronicles the advancement in the last decade in 177Lu-radiopharmacy with a focus on 177Lu produced via direct 176Lu (n, γ) 177Lu nuclear reaction in medium flux research reactors. The specific nuances of 177Lu production by various routes are described and their pros and cons are discussed. Lutetium, is the last element in the lanthanide series. Its chemistry plays a vital role in the preparation of a wide variety of radiopharmaceuticals which demonstrate appreciable in vivo stability. Traditional bifunctional chelators (BFCs) that are used for 177Lu-labeling are discussed and the upcoming ones are highlighted. Research efforts that resulted in the growth of various 177Lu-based radiopharmaceuticals in preclinical and clinical settings are provided. This review also summarizes the results of clinical studies with potent 177Lu-based radiopharmaceuticals that have been prepared using medium specific activity 177Lu produced by direct neutron activation route in research reactors. Overall, the review amply demonstrates the practicality of the medium specific activity 177Lu towards formulation of various clinically useful radiopharmaceuticals, especially for the benefit of millions of cancer patients in developing countries with limited reactor facilities.

[Conservative treatment options for symptomatic thumb trapeziometacarpal joint osteoarthritis]

BACKGROUND

There are numerous non-surgical treatment options for basal thumb osteoarthritis (OA).

OBJECTIVES

Aetiology, clinical appearance and diagnosis of basal thumb OA, explanation of the individual non-surgical treatment options, presentation of the current state of studies.

MATERIAL AND METHODS

Search for case analyses, studies, systematic reviews and meta-analyses using PubMed and LIVIVO.

RESULTS

Intraarticular injections have no more than short-term success with the risk of infection, which should not be underestimated. Radiotherapy seems to be an effective treatment, but little research has been done on this. Physiotherapy and splinting treatment promise long-term improvement of clinical symptoms and hand function.

CONCLUSION

Basal thumb OA is a common and serious condition, which in the case of continuous pain should be diagnosed and treated adequately. A multi-modal therapeutic regimen with avoidance of repetitive intra-articular injections seems to provide the best long-term results.

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.

[The Baker's cyst - a blunt sword of Damokles in radiosynoviorthesis (RSO)?]

The existence of a popliteal Baker's cyst was regarded as a contraindication for radiosynoviorthesis of the knee joint since decades. A so-called "ventile mechanism" was discussed leading to a significant concentration of the intraarticularly applied, high energy beta emitting radiopharmaceutical yttrium-90-colloid in the cyst. This cyst arises from a bursa beneath the tendon of the medial head of the gastrocnemius muscle, normally communicating with the knee joint space. Since the cyst wall is much thinner than the knee joint capsule, a radiogenic rupture of the cyst was feared, leading to severe radiogenic necroses of the surrounding soft tissue. Due to this potential hazard, knee joint ultrasound is mandatory prior to radiosynoviorthesis to check for any popliteal cysts. New studies however decline the risk of a radiogenic cyst rupture after an appropriately performed radiosynoviorthesis of the knee joint.In case of a preexistent cyst rupture, the risk of a radiogenic tissue damage remains an issue and magnetic resonance imaging (MRI) is the method of choice to exclude this potential hazard. However, MRI sometimes leads to equivocal results. Scintigraphy of the knee joint after intraarticular application of Tc-99m-nanocolloid offers the possibility to check for the integrity of the Baker's cyst in these patients to be sure that radiosynoviorthesis will not lead to a relevant extraarticular leakage with soft tissue necroses. This study describes the procedure of intracavitary distribution scintigraphy by means of representative case reports.

Mesenchymal Stem Cell-Based Therapy for Rheumatoid Arthritis

Mesenchymal stem cells (MSCs) have great potential to differentiate into various types of cells, including but not limited to, adipocytes, chondrocytes and osteoblasts. In addition to their progenitor characteristics, MSCs hold unique immunomodulatory properties that provide new opportunities in the treatment of autoimmune diseases, and can serve as a promising tool in stem cell-based therapy. Rheumatoid arthritis (RA) is a chronic systemic autoimmune disorder that deteriorates quality and function of the synovium membrane, resulting in chronic inflammation, pain and progressive cartilage and bone destruction. The mechanism of RA pathogenesis is associated with dysregulation of innate and adaptive immunity. Current conventional treatments by steroid drugs, antirheumatic drugs and biological agents are being applied in clinical practice. However, long-term use of these drugs causes side effects, and some RA patients may acquire resistance to these drugs. In this regard, recently investigated MSC-based therapy is considered as a promising approach in RA treatment. In this study, we review conventional and modern treatment approaches, such as MSC-based therapy through the understanding of the link between MSCs and the innate and adaptive immune systems. Moreover, we discuss recent achievements in preclinical and clinical studies as well as various strategies for the enhancement of MSC immunoregulatory properties.

The EANM guideline for radiosynoviorthesis

Purpose

Radiosynoviorthesis (RSO) using the intraarticular application of beta-particle emitting radiocolloids has for decades been used for the local treatment of inflammatory joint diseases. The injected radiopharmaceuticals are phagocytized by the superficial macrophages of the synovial membrane, resulting in sclerosis and fibrosis of the formerly inflamed tissue, finally leading to reduced joint effusion and alleviation of joint pain.

Methods

The European Association of Nuclear Medicine (EANM) has written and approved these guidelines in tight collaboration with an international team of clinical experts, including rheumatologists. Besides clinical and procedural aspects, different national legislative issues, dosimetric considerations, possible complications, and side effects are addressed.

Conclusion

These guidelines will assist nuclear medicine physicians in performing radiosynoviorthesis. Since there are differences regarding the radiopharmaceuticals approved for RSO and the official indications between several European countries, this guideline can only give a framework that must be adopted individually.

The use of radiosynovectomy in patients with juvenile idiopathic arthritis. Assessment of treatment efficacy and safety

Objectives

The aim of the study was to evaluate the usefulness of knee joint radiosynovectomy (RS) in patients suffering from juvenile idiopathic arthritis (JIA).

Material and methods

One hundred RS procedures performed in 58 patients with JIA in average age 10.4 years were evaluated.

Results

After 6 weeks, a decrease in the number of cases with joint pain from 90.3% to 29%, with joint oedema from 100% to 74.5%, with joint exudate from 100% to 60.6%, with gait disorders from 19.4% to 3.2%, with joint mobility disorders from 51.1% to 26.6% in the RS cases was observed. A reduction of the score in the Colorado scale from 10.9 to 4.66, in the pain visual analogue scale (VAS) from 50 to 10, in the illness VAS assessed by the patient/parent from 69.9 to 32.4, in the illness VAS assessed by the physician from 68.8 to 36.9 was observed. Six months after the RS procedure, a reduction in the number of cases with joint pain from 89.5% prior to the procedure to 29.5%, with oedema from 100% to 58.3%, with exudate from 100% to 46.9%, with gait disorders from 20% to 2.1%, with joint motility disorders from 51.1% to 26.1% was achieved. The score in the Colorado scale was reduced from 10.9 to 4.04, in the pain VAS from 40 to 0, in the illness VAS assessed by the patient/parent from 69.7 to 27.9, in the illness VAS assessed by the physician from 68.8 to 32.4. In ultrasound examinations, the greatest improvement compared to the initial condition was recorded in the 6^th month after the RS. Radiosynovectomy was positively evaluated by parents and patients in 34 anonymous surveys. Early and late observations (average 1473 days) did not show lesions at the isotope injection site, and no neoplastic lesions were observed.

Conclusions

Radiosynovectomy is a valuable therapeutic option for local treatment in patients with JIA.

Low-dose radiation therapy for osteoarthritis and enthesopathies: a review of current data

BACKGROUND

Osteoarthritis (OA), the most common degenerative joint disease, is associated with severe functional limitation and impairment of quality of life. Numerous reports have documented the clinical efficacy of low-dose radiotherapy (LD-RT) in the management of various inflammatory disorders, including OA. In this paper, we assessed the clinical literature involving the use of LD-RT in the treatment of OA, its dose-response features, possible underlying mechanistic features, and optimal therapeutic dose range.

METHODS

We carried out a systematic review based on the guidelines of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statements and evaluated articles meeting the inclusion criteria for this review.

RESULTS

A total of 361 articles were identified from databases, such as Scopus, PubMed, Embase, and Science Direct out of which 224 articles were duplicates and were discarded. Of the remaining 137 articles, 74 articles were un-related, 27 articles were review articles, eight were conference abstracts, three were letters, two were editorials, two were notes, and one was a book chapter. Finally, 20 articles met all the inclusion criteria and were included in this systematic review.

DISCUSSION

Several single-arm retrospective/prospective studies showed advantages for LD-RT in the management of OA in terms of pain relief, improvement of mobility and function, and showed minimal side effects. Mechanistic considerations involve positive subcellular effects mediated by the activation of a nuclear factor erythroid 2-related transcription factor (Nrf2) mediated antioxidant response. Further research on both the short- and long-term effects of LD-RT on OA and other inflammatory disorders is recommended.

Prospective Clinical Evaluation of Intra-Articular Injection of Tin-117m (117mSn) Radiosynoviorthesis Agent for Management of Naturally Occurring Elbow Osteoarthritis in Dogs: A Pilot Study

Purpose

To evaluate the clinical effects of an intra-articular injection of ^117mSn-colloid for management of canine grade 1 or 2 elbow osteoarthritis (OA).

Patients and Methods

This was a prospective study in 23 dogs with grade 1 or 2 elbow OA. An orthopedic examination and elbow radiographs were performed to confirm the presence of OA. Dogs were randomly assigned to receive unilateral intra-articular (IA) injection of low-dose (LD: 1.0mCi, n =8), medium-dose (MD: 1.75mCi, n =6), or high-dose (HD: 2.5mCi, n =9) of ^117mSn-colloid. The primary outcome measure was peak vertical force (PVF) from force-plate gait analysis and secondary outcome measures included the Canine Brief Pain Inventory score (CBPI) and elbow goniometry. The CBPI was evaluated at pretreatment and then monthly post treatment for 1 year, and goniometry and PVF were evaluated at pretreatment, and at 1, 3, 6, 9 and 12 months post treatment.

Results

PVF improved at 3, and 9 months compared to pretreatment values in the HD group. CBPI scores improved at most of the time points in all dose groups. There was no significant difference in elbow goniometry between treated and untreated elbows. There were no self-reports of any adverse effects of the injection by the owners and none were noted by the examining veterinarian at the time of regularly scheduled re-evaluations.

Conclusion

^117mSn IA injection was free of any obvious adverse effects, improved CBPI scores, and increased weight bearing in limbs with elbow OA providing preliminary evidence that ^117mSn may be beneficial in the management of elbow OA in dogs. Although ^17mSn appeared to be effective for management of elbow OA in these dogs, this pilot study has inherent limitations; therefore, future studies with larger numbers and with placebo group are needed.

Production of Mass-Separated Erbium-169 Towards the First Preclinical in vitro Investigations

The β--particle-emitting erbium-169 is a potential radionuclide toward therapy of metastasized cancer diseases. It can be produced in nuclear research reactors, irradiating isotopically-enriched 168Er2O3. This path, however, is not suitable for receptor-targeted radionuclide therapy, where high specific molar activities are required. In this study, an electromagnetic isotope separation technique was applied after neutron irradiation to boost the specific activity by separating 169Er from 168Er targets. The separation efficiency increased up to 0.5% using resonant laser ionization. A subsequent chemical purification process was developed as well as activity standardization of the radionuclidically pure 169Er. The quality of the 169Er product permitted radiolabeling and pre-clinical studies. A preliminary in vitro experiment was accomplished, using a 169Er-PSMA-617, to show the potential of 169Er to reduce tumor cell viability.

A Review on Rheumatoid Arthritis Interventions and Current Developments

Rheumatoid arthritis is a chronic autoimmune disorder characterized by inflammation, swelling, and joint destruction primarily affecting the peripheral joints. In recent years, RA has become an alarming concern affecting more than 1.5% of the population worldwide. The majority of the drugs in clinical trials for rheumatoid arthritis are immunomodulatory. The development of novel drugs for RA is impending and scientists are exploring new strategies through various innovative approaches for RA drug development. Treat-to-target and window of opportunity hypothesis are the new approaches that are used to treat, improve outcomes, and prevent long-term use of ineffective therapy, respectively. Novel therapeutic agents (e.g. GM-CSF inhibitors, Matrix metalloproteinase inhibitors) and delivery systems (e.g., Liposomes, Superparamagnetic iron oxide nano particles (SPIONs)) are under investigation for more target based therapy with reduced side effects and toxicity. The new drug discovery and repositioning of previously FDA-approved drugs are also being considered for chronic inflammatory disorder. The review encompasses a vast array of information, including genetics, etiology, clinical symptoms, current treatment, and newer therapeutics approaches, focused on the development of RA interventions. The introduction of the bioinformatics-based approach in RA has also been significantly discussed in the review. This review provides a general understanding of the challenges and uncertainties in the treatment of RA and summarizes the evolving scenario as well as innovative approaches taken into consideration for drug development in rheumatoid arthritis.

Medicinal inorganic chemistry: an updated review on the status of metallodrugs and prominent metallodrug candidates

Metallodrugs correspond to a small portion of all available drugs in the market and, yet, some of them are among the most used and important drugs in modern medicine. However, medicinal inorganic chemistry remains an underestimated area within medicinal chemistry and the main reason is the mislead association of metals to toxic agents. Thus, in this review, the potential of medicinal inorganic chemistry in drug designing is highlighted through a description of the current status of metallodrugs and metallodrug candidates in advanced clinical trials. The broad spectrum of application of metal-based drugs in medicine for both therapy and diagnosis is addressed by the extensive list of examples presented herein.

90Y Radiosynovectomy in Persistent Synovitis Caused by Knee Replacement: Long-Term Outcome

INTRODUCTION

After knee replacement, therapy resistant, persistent synovitis is a common issue, which causes effusion and pain, and leads to loosing. It has been hypothesized that radiosynovectomy (RSO) is useful in these patients.

MATERIALS AND METHODS

A cohort of 55 patients with 57 knee replacements and persistent synovitis underwent RSO using 4.9 ± 0.24 mCi (182 ± 9 MBq) of Y-citrate. The number of RSOs ranged from 1 to 4. Bone scans before and 3 months after every RSO were performed. Long-term follow-up ranged from 0.8 to 7.6 years with a mean of 23.2 months. For qualitative analysis, an established 4 steps scoring was used. For quantification, the uptake was determined within the Tc-MDP scintigraphy blood pool phase before and after therapy.

RESULTS

Long-term response was in 27% with excellent, 24% good, 30% weak, and 20% no response. The duration of response was 12.0 ± 12.0 months (maximum, 54 months). In patients with repeated treatment, the effect after the first therapy was lesser than in patients who received a single treatment in total. However, 3 months after the last RSO, patients with repeated treatment showed a similar effectiveness than single treated patients. At the end of long-term follow-up, patients with repeated RSOs had a higher effectiveness at similar duration response. In bone scan, 65% of patients showed a reduction of uptake. When comparing subjective and objective response, 78% of patients showed a concordance in both symptoms and scintigraphy. Pilot histological analysis revealed that the synovitis is triggered by small plastic particles.

CONCLUSIONS

We concluded that RSO is an effective therapy in patients with knee replacement and persistent synovitis with high long-term response. Repeated treatment leads to a stronger long-time response.

Energy Conversion-Based Nanotherapy for Rheumatoid Arthritis Treatment

Rheumatoid arthritis (RA) is characterized by synovial hyperplasia and cartilage/bone destruction, which results in a high disability rate on human health and a huge burden on social economy. At present, traditional therapies based on drug therapy still cannot cure RA, in accompany with the potential serious side effects. Based on the development of nanobiotechnology and nanomedicine, energy conversion-based nanotherapy has demonstrated distinctive potential and performance in RA treatment. This strategy employs specific nanoparticles with intrinsic physiochemical properties to target lesions with the following activation by diverse external stimuli, such as light, ultrasound, microwave, and radiation. These nanoagents subsequently produce therapeutic effects or release therapeutic factors to promote necrotic apoptosis of RA inflammatory cells, reduce the concentration of related inflammatory factors, relieve the symptoms of RA, which are expected to ultimately improve the life quality of RA patients. This review highlights and discusses the versatile biomedical applications of energy conversion-based nanotherapy in efficient RA treatment, in together with the deep clarification of the facing challenges and further prospects on the final clinical translations of these energy conversion-based nanotherapies against RA.

Radiopharmaceutical therapy in cancer: clinical advances and challenges

Radiopharmaceutical therapy (RPT) is emerging as a safe and effective targeted approach to treating many types of cancer. In RPT, radiation is systemically or locally delivered using pharmaceuticals that either bind preferentially to cancer cells or accumulate by physiological mechanisms. Almost all radionuclides used in RPT emit photons that can be imaged, enabling non-invasive visualization of the biodistribution of the therapeutic agent. Compared with almost all other systemic cancer treatment options, RPT has shown efficacy with minimal toxicity. With the recent FDA approval of several RPT agents, the remarkable potential of this treatment is now being recognized. This Review covers the fundamental properties, clinical development and associated challenges of RPT.

Radiopharmaceutical therapy is emerging as a safe and effective approach for the treatment of cancer, offering several advantages over existing therapeutic strategies. Here, Sgouros and colleagues provide an overview of the fundamental properties of radiopharmaceutical therapy, discuss agents in use and in clinical development and highlight the associated translational challenges.

Radiosynoviorthesis after Surgery in the Treatment of Patients with Ankle Pigmented Villonodular Synovitis: A Case Series

Pigmented villonodular synovitis (PVNS) of the ankle is a very rare, locally aggressive, proliferative disorder. Although surgical excision represents the standard curative treatment, the PVNS relapse rate is high. We present our study of five young athletes (range 20–36 years) with a histopathological diagnosis of PVNS of the ankle, who were treated by surgery and adjuvant radiosynoviorthesis (RSO). The operation involved either arthroscopic (four patients) or open (one patient) debridement, followed by intraarticular RSO with the radiopharmaceutical erbium-169 (¹⁶⁹Er). They were evaluated with the Foot Function Index (FFI) and a visual analog scale (VAS) for pain. At a median follow up period of 47 months (range 36–54 months), all five patients reported marked pain relief with improvements in their daily activities. In particular, the median FFI decreased from 77% (range 71.0%–84.5%) pre-treatment, to 0.5% (range 0%–6%) after treatment. The median VAS score decreased from 4 (range 3–7) to 0 (range 0–1), respectively. Throughout the follow-up period, there were no major complications regarding either therapeutic intervention (arthroscopic or open debridement, RSO). Based on these results, it can be concluded that adjuvant RSO with ¹⁶⁹Er following surgical excision is effective and safe in the treatment of PVNS of the ankle.

Yttrium-90 Synovectomy in Hemophilic Arthropathy: An Institutional Experience for 15 Years

OBJECTIVE

The objective of this study is to assess the efficacy of Yttrium-90 (Y-90) radiation synovectomy in decreasing the recurrent bleeding episodes in hemophilic joints.

SUBJECTS AND METHODS

A retrospective analysis of patients who had Y-90 synovectomy from January 2001 to January 2016 was done. Among them, patients with minimum follow-up of 6 months were selected. The response in terms of decrease in the number of bleeding episodes was evaluated.

RESULTS

A total of 167 patients (243 joints) with hemophilia had radiation synovectomy over 15 years. Those with a minimum follow-up of 6 months were 155 joints (115 patients). The age ranged from 5 to 43 years and included 113 male and two female patients. Data for 11 joints were unavailable as these patients were lost to follow-up. The assessment of response for the remaining 144 joints was done based on the data available for different follow-up periods. They were divided into the following - 7 months to 2 years (89 joints), 3-5 years (6 joints), 6-10 years (39 joints), and above 11 years (10 joints). Overall, 37.4% of the joints had complete response, 56% had partial response, and 6% of the joints had no response.

CONCLUSION

Radiation synovectomy is a noninvasive and effective modality which decreases the bleeding episodes in hemophiliac joints and improves the quality of life remarkably.

All-Trans Retinoic Acid Inhibits Migration and Invasiveness of Rheumatoid Fibroblast-Like Synoviocytes

Fibroblast-like synoviocytes (FLSs) are pivotal in inflammation and joint damage of rheumatoid arthritis (RA). They acquire an active and aggressive phenotype, displaying increased migration and invasiveness and contributing to perpetuate synovial inflammation and destruction of cartilage and bone. The main current therapies of RA are focused against inflammatory factors and immune cells; however, a significant percentage of patients do not successfully respond. Combined treatments with drugs that control inflammation and that reverse the pathogenic phenotype of FLS could improve the prognosis of these patients. An unexplored area includes the retinoic acid, the main biologic retinoid, which is a candidate drug for many diseases but has reached clinical use only for a few. Here, we explored the effect of all-trans retinoic acid (ATRA) on the aggressive phenotype of FLS from patients with RA. RA FLSs were treated with ATRA, tumor necrosis factor (TNF), or TNF+ATRA, and cell migration and invasion were analyzed. In addition, a microarray analysis of expression, followed by gene-set analysis and quantitative polymerase chain reaction validation, was performed. We showed that ATRA induced a notable decrease in FLS migration and invasion that was accompanied by complex changes in gene expression. At supraphysiological doses, many of these effects were overridden or reverted by the concomitant presence of TNF. In conclusion, these results have demonstrated the therapeutic potential of retinoic acid on RA FLS provided TNF could be counterbalanced, either with high ATRA doses or with TNF inhibitors. SIGNIFICANCE STATEMENT: All-trans retinoic acid (ATRA) reduced the rheumatoid arthritis (RA) fibroblast-like synoviocyte migration and invasiveness and down-regulated gene expression of cell motility and migration genes. At supraphysiological doses, some of these effects were reverted by tumor necrosis factor. Therefore, ATRA could be an RA drug candidate that would require high doses or combined treatment with anti-inflammatory drugs.

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

OBJECTIVE

The aim of this study was to assess the treatment results of ⁹⁰Y radiation synovectomy for chronic exudative synovitis of knee joints.

METHODS

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.

RESULTS

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.

CONCLUSIONS

(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.

ICRP Publication 140: Radiological Protection in Therapy with Radiopharmaceuticals

Radiopharmaceuticals are increasingly used for the treatment of various cancers with novel radionuclides, compounds, tracer molecules, and administration techniques. The goal of radiation therapy, including therapy with radiopharmaceuticals, is to optimise the relationship between tumour control probability and potential complications in normal organs and tissues. Essential to this optimisation is the ability to quantify the radiation doses delivered to both tumours and normal tissues. This publication provides an overview of therapeutic procedures and a framework for calculating radiation doses for various treatment approaches. In radiopharmaceutical therapy, the absorbed dose to an organ or tissue is governed by radiopharmaceutical uptake, retention in and clearance from the various organs and tissues of the body, together with radionuclide physical half-life. Biokinetic parameters are determined by direct measurements made using techniques that vary in complexity. For treatment planning, absorbed dose calculations are usually performed prior to therapy using a trace-labelled diagnostic administration, or retrospective dosimetry may be performed on the basis of the activity already administered following each therapeutic administration. Uncertainty analyses provide additional information about sources of bias and random variation and their magnitudes; these analyses show the reliability and quality of absorbed dose calculations. Effective dose can provide an approximate measure of lifetime risk of detriment attributable to the stochastic effects of radiation exposure, principally cancer, but effective dose does not predict future cancer incidence for an individual and does not apply to short-term deterministic effects associated with radiopharmaceutical therapy. Accident prevention in radiation therapy should be an integral part of the design of facilities, equipment, and administration procedures. Minimisation of staff exposures includes consideration of equipment design, proper shielding and handling of sources, and personal protective equipment and tools, as well as education and training to promote awareness and engagement in radiological protection. The decision to hold or release a patient after radiopharmaceutical therapy should account for potential radiation dose to members of the public and carers that may result from residual radioactivity in the patient. In these situations, specific radiological protection guidance should be provided to patients and carers.

Design, synthesis and characterization of hydroxyapatite-chitosan nanocomposite radiolabelled with 153Sm as radiopharmaceutical for use in radiosynovectomy

The aim of the present study was to introduction of hydroxyapatite/chitosan nanocomposite as a new radiosynovectomy agent with excellent properties. In this work, the nanocomposite was prepared through a reliable method and characterized using different techniques to elucidate its chemical structure and physiochemical properties. The prepared nanocomposite was successfully radiolabeled with 153Sm under optimal conditions and with high radiolabelling yield (99 %). The radiochemical purity of the prepared radiopharmaceutical was found to be >99 % as determined by ITLC technique. In vitro stability studies in saline solution and in human serum showed that the radiolabeled nanocomposite retained its stability for at least 6 days. The biodistribution and imaging studies in wild-type rats revealed high retention of the agent into the synovial joints of the knee even at 96 h post-injection, thereby indicating excellent in vivo stability of 153Sm labeled hydroxyapatite-chitosan nanocomposite. Therefore, the prepared radiopharmaceutical would be a potential therapeutic agent for use in radiosynovectomy procedure.

Intraarticular injection of a Tin-117 m radiosynoviorthesis agent in normal canine elbows causes no adverse effects

This longitudinal prospective exploratory study used serial measurements in five dogs to evaluate safety and retention of a tin-117 m (^117m Sn) colloid after intra-articular injection in normal elbow joints. Each dog was deemed healthy based on physical examination, laboratory results, and radiographic evaluation of both elbows. While anesthetized, each received an MRI of both elbows, followed by fluorine-18 fluorodeoxyglucose positron emission tomography scans of both elbow joints and associated lymph nodes. Joint fluid (0.5-1.0 mL) was withdrawn aseptically from the left elbow joint, followed by intra-articular injection of ^117m Sn colloid (92.5 MBq; 1-1.5 ml). Post-injection assessments included blood counts, serum chemistry panels, urinalyses, radiographs, joint fluid analyses, MRI/positron emission tomography scans, scintigraphy, and biodistribution scans. On day 45-47, each dog was euthanized and a complete postmortem examination was performed. Tissue samples were submitted for histopathology and radioisotope retention studies. Left elbow joints were decalcified and sectioned for future autoradiography. Scintigraphy, 1 day after injection, indicated slight radioisotope escape from the joint to regional lymph nodes. Serial blood, urine, feces, and organ counts indicated >99.1% of the ^117m Sn activity was retained in the joint for 45-47 days. Radiation output levels were below patient release levels the day following injection. Maximum standard uptake value for the injected joint decreased. Joint fluid cytology was unchanged. No dog exhibited lameness during the study. Absence of joint damage and lack of systemic effects after injection of the ^117m Sn colloid in normal canine elbow joints indicate that this agent may be safely used for radiosynoviorthesis in dogs with osteoarthritis.

Updated Treatment for Calcium Pyrophosphate Deposition Disease: An Insight

Calcium pyrophosphate disease (CPPD) is caused by the deposition of calcium pyrophosphate (CPP) crystals in the joint tissues, particularly fibrocartilage and hyaline cartilage. CPP crystals trigger inflammation, causing local articular tissue damage. Our review article below covers different aspects of CPPD. It discusses how CPPD can manifest as different kinds of arthritis, which may be symptomatic or asymptomatic. The metabolic and endocrine disease associations and routine investigations used in the diagnostic workup are briefly reviewed. Conventional and newer therapies for the treatment of CPPD are outlined. Overall, this extensive review would provide an updated insight to clinicians for evidence-based treatment of CPPD.

[The knee joint in rheumatoid arthritis-current orthopaedic surgical treatment options]

The knee joint is often involved in rheumatoid arthritis. Despite ever-improving medical antirheumatic therapies, surgical treatment continues to play an important role in optimal multidisciplinary care. The aim of the present work is to process current orthopedic surgical therapy procedures on the knee joint according to disease stage. In the early phase, joint-preserving arthroscopic procedures for synovectomy are used. In advanced joint destruction, joint function can be restored by total knee arthroplasty. Of central importance for optimal patient care are individual treatment and good interdisciplinary coordination of all involved specialist groups.

Beta burns following radionuclide synovectomy

Radionuclide synovectomy (RSV) is a form of minimally invasive treatment of persistent joint inflammation. The procedure has a high safety profile and the occurrence of serious adverse events, such as full-thickness skin radiation necrosis, is rare. Less severe radiation events, while more common, are usually benign and self-limiting. We present two cases of low-grade beta burns that developed after RSV, despite proper injection technique. The potential long-term risk of such exposure is also discussed, with reference to historical radiation incidents. While low-grade beta burns after RSV usually pose little danger to the patient, any clinician involved in radionuclide treatment of arthritis should be aware of their existence and management.

The Tumor-Like Phenotype of Rheumatoid Synovium: Molecular Profiling and Prospects for Precision Medicine

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by destructive hyperplasia of the synovium. Fibroblast-like synoviocytes (FLS) are a major component of synovial pannus and actively participate in the pathologic progression of RA. How rheumatoid FLS acquire and sustain such a uniquely aggressive phenotype remains poorly understood. We describe the current state of knowledge of the molecular alterations in rheumatoid FLS at the genomic, epigenomic, transcriptomic, proteomic, and metabolomic levels, which offers a means to reconstruct the pathways leading to rheumatoid pannus. Such data provide new pathologic insight and suggest means to more sensitively assess disease activity and response to therapy, as well as support new avenues for therapeutic development.

Dosimetry perspectives in radiation synovectomy

Rheumatoid arthritis (RA) is a chronic inflammatory disease that can potentially damage the synovial joints. One of the effective treatment modality for RA is radiation synovectomy (RSV) where properly selected radionuclide is injected into the joint space, enabling controlled destruction of diseased synovial membrane via radiation exposure. Radiation dosimetry in RSV appears challenging due to the heterogeneous nature of synovial membrane, nonuniform distribution and leakage of radionuclide from the synovial cavity. This article reviews the dosimetric perspective pertaining to RSV. Specifically, characteristics of radionuclide for RSV and radiation dose to target and non-target (i.e., articular cartilage, bone, bloodstream, gonads, etc.) tissues of patient have been discussed. The personal dose H_p(0.07) to the hands of medical staff (i.e., radiochemist, therapist physician, nurse) may be considerably high due to handling of high specific activities (∼500 MBq/ml for Y-90); such doses are typically measured using thermoluminescence dosimeters (TLD) ring dosimeters and ranges from 1 to 21.5, 0.1 to 40 and 0.1 to 5 µSv/MBq for the radiochemist, therapist physician and the nurse, respectively. Methods to minimize radiation doses to the patient, medical staff and public are elaborated. Contamination risks and precautionary measures are also reported.

Rheumatoid Arthritis: A Brief Overview of the Treatment

Rheumatoid arthritis (RA) is a chronic, inflammatory, systemic autoimmune disease, affecting the joints with varying severity among patients. The risk factors include age, gender, genetics, and environmental exposure (cigarette smoking, air pollutants, and occupational). Many complications can follow, such as permanent joint damage requiring arthroplasty, rheumatoid vasculitis, and Felty syndrome requiring splenectomy if it remains unaddressed. As there is no cure for RA, the treatment goals are to reduce the pain and stop/slow further damage. Here, we present a brief summary of various past and present treatment modalities to address the complications associated with RA.

Formulation and characterization of lutetium-177-labeled stannous (tin) colloid for radiosynovectomy

OBJECTIVE

Easy large-scale production, easy availability, cost-effectiveness, long half-life, and favorable radiation characteristics have made lutetium-177 (Lu) a preferred radionuclide for use in therapy. Lutetium-177-labeled stannous (Lu-Sn) colloid particles were formulated for application in radiosynovectomy, followed by in-vitro and in-vivo characterization.

METHODS

Stannous chloride (SnCl2) solution and Lu were heated together, the pH was adjusted, and the particles were recovered by centrifugation. The heating time and amount of SnCl2 were varied to optimize the labeling protocol. The labeling efficiency (LE) and radiochemical purity (RCP) of the product were determined. The size and shape of the particles were determined by means of electron microscopy. In-vitro stability was tested in PBS and synovial fluid, and in-vivo stability was tested in humans.

RESULTS

LE and RCP were greater than 95% and ∼99% (Rf=0-0.1), respectively. Aggregated colloidal particles were spherical (mean size: 241±47 nm). The product was stable in vitro for up to 7 days in PBS as well as in synovial fluid. Injection of the product into the infected knee joint of a patient resulted in its homogenous distribution in the intra-articular space, as seen on the scan. No leakage of activity was seen outside the knee joint even 7 days after injection, indicating good tracer binding and in-vivo stability.

CONCLUSION

Lu-Sn colloid was successfully prepared with a high LE (>95%) and high RCP (99%) under optimized reaction conditions. Because of the numerous benefits of Lu and the ease of preparation of tin colloid particles, Lu-Sn colloid particles are significantly superior to its currently available counterparts for use in radiosynovectomy.

Persistent cutaneous ulcers after Yttrium-90 synovectomy, an unusual complication: two case reports and a review of the literature

Development of persistent deep cutaneous ulceration is a rare and serious complication of radiosynovectomy, an extended procedure used in the treatment of chronic synovitis. Cutaneous radiation necrosis is a rare complication of synovectomy, probably as a result of radiocolloid para-articular injection. This rare phenomenon should be suspected when an ulcer adjacent to an articulation appears several days or even months after a radiation synovectomy. It can turn into a challenging diagnosis for rheumatologists, orthopaedists and dermatologists, especially in those cases with a late development of the skin lesions. Recognition of this potential side effect is important in order to establish a proper therapeutic strategy and avoid unnecessary treatments. Surgical excision appears to be the treatment of choice. We report two patients with knee osteoarthritis treated with intra-articular injection of Yttrium-90 who developed persistent cutaneous ulcers secondary to radiation necrosis.

Radionuclide synovectomy - essentials for rheumatologists

Radionuclide synovectomy is a minimally invasive method of treating persistent joint inflammation. It involves intra-articular injection of radioactive colloids which induce necrosis and fibrosis of hypertrophic synovial membrane. The most common indication for radiosynovectomy is rheumatoid arthritis, although patients with seronegative spondyloarthropathies, unclassified arthritis, haemophilic arthropathy and other less common arthropathies can also benefit from this method. Radiosynovectomy is safe, well tolerated and efficacious. About 70–80% of patients respond well to the therapy. However, the therapeutic effects are considerably worse in patients with co-existent osteoarthritis and advanced joint degeneration. Despite its advantages, radionuclide synovectomy is not performed as often as it could be, so greater knowledge and understanding of this method are needed. The authors present the most important facts about radiosynovectomy that may help rheumatologists in their daily clinical practice.