Chromic phosphate-32 colloid radiosynovectomy for the treatment of haemophilic synovitis: A long-term follow-up study

Efficient production and purification of 32P radioisotope from sulfur by dry distillation: A practical approach with high radiochemical purity

The 32P radioisotope, with a half-life of 14.3 days and an energy level of 1.71 MeV, has diverse applications in medicine and research. Consequently, producing a carrier-free 32P radioisotope characterized by high radiochemical and radionuclide purity is imperative. Two primary methods for generating 32P radioisotopes exist: irradiating phosphorus through the nuclear reaction (n,γ) or irradiating sulfur through the nuclear reaction (n,p). Using sulfur as a target material provides several advantages. Besides the fact that the chemical element produced after irradiation (32P) differs from the irradiated element (32S), it also produces a32P radioisotope with a higher specific activity than using 31P as the target. The production of the radioisotope 32P from sulfur employs the dry distillation method, capitalizing on sulfur's easily sublimated nature. The volatility of sulfur when heated makes it easy to separate the resulting sulfur and radioisotope 32P without the need for additional reagents. This research aims to establish a practical method for producing the 32P radioisotope using the dry distillation technique. The dry distillation method utilizes a quartz ampoule containing a mixture of 32P and 35S radionuclides, a distillation tube wrapped with heating tape, and a condenser to collect the distilled sulfur. Sulfur, serving as the target material, undergoes irradiation in the reactor at the Central Irradiation Position (CIP) through the 32S(n,p)32P nuclear reaction with a fast neutron flux of 5.380 × 1013 n/cm2.sec. Separation is achieved through distillation at a temperature of 440 °C. The residual separation products are then dissolved in a 0.1 N HCl solution. The purification process involves using an AG50 WX8 cation exchange resin column, which is pre-conditioned with 0.1 N HCl. The resulting eluate contains the 32P radioisotope. The radiochemical purity of the 32P radioisotope is analyzed using thin-layer chromatography (TLC). In this analysis, a PEI Cellulose plate serves as the stationary phase, and a KH2PO4 solution acts as the mobile phase. This vacuum-free distillation method successfully separates the 32P radioisotope from sulfur, achieving a separation efficiency of 55.1 ± 9.9% (n = 7). The average activity produced after the purification process is 5.690E+10 Bq. Purifying the 32P radioisotope results in a radiochemical purity of 99.97% at Rf 0.7110, as orthophosphate, the radionuclide purity exceeds 99%.

Radiosynovectomy in haemophilic synovitis and arthropathy of the knee: A scoping review

INTRODUCTION

Radiosynovectomy is an established treatment for chronic synovitis in patients with haemophilia. Although its role in rheumatological diseases has diminished, it remains an accepted therapy for haemophilic synovitis.

AIM

The aim of this scoping review was to map and summarise the evidence surrounding radiosynovectomy in haemophilic knees, identify gaps in the literature and inform future research.

RESULTS

Forty-three manuscripts and abstracts were identified for this review. Evidence was limited to observational studies and Yttrium-90 was the most studied licensed radioisotope. Radiosynovectomy was associated with a reduction in bleeding frequency and pain, improvements in range of motion and a reduction in the use of factor replacement.

CONCLUSION

The literature reviewed lacks studies of sufficient methodological quality to permit systematic review and meta-analysis. Systematic review using risk of bias assessment for observational studies should be undertaken to better evaluate the efficacy and safety of radiosynovectomy. A causal relationship between RSV and key clinical outcomes remains undetermined.

Synovitis in hemophilia: preventing, detecting, and treating joint bleeds

INTRODUCTION

Most bleeding events in individuals with hemophilia occur within the ankle, knee, and elbow joints. Should the bleeding persist, the synovial membrane starts to hypertrophy and a vicious cycle of chronic hemophilic synovitis (CHS) occurs, leading to joint destruction.

AREAS COVERED

This article covers the prompt diagnosis of CHS by point-of-care ultrasonography (POC-US) and its treatment by means of several types of synovectomy.

EXPERT OPINION

It is essential to prevent, detect and treat hemophilic synovitis, because it indicates that the joint has bled and is at risk of bleeding further. Prophylaxis with standard half life (SHL) factor VIII (FVIII) concentrate is the standard of care for individuals with severe hemophilia A and can also be considered for selected patients with moderate disease. Several years of real-world experience with extended half life (EHL) FVIII, emicizumab, and other drugs in development will be needed to ascertain their final effect on bleeding and its complications. We must look for synovitis in individuals declaring joint pain and in asymptomatic patients, and POC-US is the most reasonable imaging instrument with which to carry out periodic joint screening. Radiosynovectomy, chemical synovectomy, and arthroscopic synovectomy markedly reduce bleeding events.

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.

Hemophilic arthropathy: a teaching approach devoted to hemophilia treaters in under-development countries

INTRODUCTION

Arthropathy is the characteristic injury of hemophilia, primarily occurring in the elbows, knees, and ankles. The aim of this review is a teaching approach devoted to hemophilia treaters in under-development countries.

AREAS COVERED

Current major challenges include the absence of the following therapeutic tools for all people with hemophilia (PWH) worldwide: hematological prophylaxis; well-coordinated multidisciplinary teams in specialized centers; joint aspiration of acute hemarthrosis; point-of-care ultrasonography (POC-US); exercise; treatment of synovitis by means of radiosynovectomy; treatment of mild hemophilic arthropathy with analgesics, anti-inflammatory agents, and rehabilitation medicine; intra-articular injections of corticosteroids, hyaluronic acid, platelet-rich plasma, and mesenchymal stem cells; and treatment of severe hemophilic arthropathy by surgical treatment. The future scenario in under-development countries should include all the aforementioned treatment tools plus the possibility of performing total joint arthroplasty in PWH with inhibitors; concomitant use of bypassing agents with emicizumab for PWH with inhibitors undergoing orthopedic surgery; and telemedicine.

EXPERT OPINION

Primary hematological prophylaxis is now the gold standard for the management of hemophilia. Acute hemarthrosis needs intense hematological management and articular aspiration; the articular situation should be scrutinized by POC-US. Synovitis can be controlled by radiosynovectomy. In cases of severe articular degeneration, surgical procedures might be required.