Sinoviortesis con radioisótopos en hemofilia: Experiencia de un centro en Chile / Radionuclide synoviorthesis in hemophilia: experience in 107 patients

Background: In patients with hemophilia, radionuclide synoviorthesis, or the intra-articular injection of a radionuclide to decrease the synovial hypertrophy tissue, aims to decrease or avoid hemarthrosis. Aim: To evaluate the effectiveness of radionuclide synoviorthesis in hemophilia. Material and Methods: Observational retrospective study of the evolution of 107 male patients aged 3 to 54 years who were subjected to radionuclide synoviorthesis between 2007 and 2015. Results: Of 164 treated joints, in 65% treatment was successful, (defined as zero to two hemarthroses and absence of synovitis during the follow up period), in 17% it was partially successful (defined as two or less hemarthroses, but persistence of the synovitis) and failed in 18% of the procedures. No important complications were recorded. Conclusions: Radionuclide synoviorthesis has an overall 82% success rate, is minimally invasive, can be used at any age and is inexpensive We recommend its implementation in Chilean hemophilia treatment centers.

Radiosinovectomía de muñeca guiada por ultrasonido: experiencia de un caso clínico y revisión del tema / Ultrasound-guided wrist radiosynovectomy: case report and topic review

Radiosynovectomy is a local form of radiotherapy used as second-line treatment in the management of inflammatory and non-inflammatory arthropathies with unsatisfactory response to local or systemic corticosteroid therapy. Its efficacy is similar to that of surgical synovectomy, with the advantages of being a low-cost and minimally- invasive treatment that requires a shorter recovery time. Its efficacy is greater in the treatment of inflammatory arthritis characterized by synovitis, such as rheumatoid arthritis and juvenile chronic arthritis with mono/oligoarticular involvement, especially in upper extremity joints. A number of isotopes can be used in colloidal suspensions. Rhenium-186-sulphide colloid is currently indicated for the treatment of medium-sized joints. The ultrasound-guided injection is suitable for small joints, such as wrist. For proper and safe use and administration of this technique the collaboration of a trained and experienced radiologist is critical to successful treatment.

La radiosinovectomía es una forma local de radioterapia utilizada como tratamiento de segunda línea en el manejo de artropatías inflamatorias y no inflamatorias con respuesta insatisfactoria a la terapia sistémica o local con corticoesteroides. Tiene una eficacia similar a la sinovectomía quirúrgica, con las ventajas de ser un tratamiento de menor costo, menos cruento y con menor tiempo de convalecencia. Su eficacia es mayor en artropatías inflamatorias caracterizadas por sinovitis, como la artritis reumatoide y artritis crónica juvenil, con compromiso mono u oligoarticular y en articulaciones de extremidades superiores. Existen múltiples isótopos que se pueden utilizar en suspensiones coloidales, siendo el sulfuro coloidal de renio-186 el utilizado para la articulación radiocarpiana. Una técnica de administración adecuada es fundamental para el éxito del tratamiento, siendo la inyección con guía ultrasonográfica adecuada para articulaciones de volumen pequeño, instancia en la que la colaboración del médico radiólogo entrenado es fundamental.

Assessment of ¹⁸⁸Re marked anti MHC class II antibody by peripheral blood mononuclear cells stimulated by donor alloantigen / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Previous studies showed that anti MHC-II monoclone antibody (MAb) only had partial inhibiting effect of alloreactive mixed lymphocyte reaction (MLR) in vitro and it was unsteady and non-persistent. The aim of this research was to determine whether radioactive isotope (188)Re marked MHC-II antibody could benefit the allograft acceptance in transplantation as compared to normal MHC-II antibody.</p><p><b>METHODS</b>188Re was incorporated to 2E9/13F (ab')(2) which is against swine MHC class II antigen (MAb-(188)Re). Porcine peripheral blood mononuclear (PBMC) cells were examined for proliferation and cytokine mRNA expression after stimulation with MHC-II MAb or MAb-(188)Re.</p><p><b>RESULTS</b>The proliferative response of recipient PBMCs in mixed lymphocyte reaction (MLR) to donor alloantigen showed that the stimulation index of MAb-(188)Re group was significantly lower than the MHC-II MAb group and control (P < 0.05). mRNA expression of interleukin 2, interferon Υ and tumor necrosis factor α (type 1 cytokines) was lower in MAb-(188)Re group than the MHC-II MAb group, while interleukin 10 (type 2 cytokines) was higher in MAb-(188)Re group in the first 24 hours.</p><p><b>CONCLUSION</b>MAb-(188)Re could help the graft acceptance by inhibiting T cell proliferation, lowering the expression of type 1 cytokines and elevating the type 2 cytokines produced by PBMC.</p>

Curative effect of stereotactic 186Re endocavitary irradiation on cystic craniopharyngioma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the treatment results of stereotactic (186)Re intracavitary irradiation in the patients with craniopharyngioma.</p><p><b>METHODS</b>Nineteen patients were treated with stereotactic (186)Re intracavitary irradiation, including 12 males and 7 females (average age, 37.2 years). Among them 12 patients had a solitary cyst, whereas 7 patients with mixed structure (e.g., a large cyst with a small solid portion). The mean volume of the cystic portion of the tumor before irradiation was 8390 mm(3).</p><p><b>RESULTS</b>The patients were followed up for 6 months to 3 years. The retraction of the cyst was complete in 7 patients, cyst volume decreased more than 50% in 5 patients and less than 50% in 7 cases. Among the 8 patients with visual acuity deficit before irradiation, 5 were improved. No hypopituitarism occurred in patients with normal pituitary function before treatment. One of the 4 patients with hypopituitarism was improved, 3 of the 5 patients with diabetes insipidus was improved.</p><p><b>CONCLUSION</b>Stereotactic (186)Re endocavitary irradiation for the treatment of cystic craniopharyngioma is a safe and effective procedure.</p>

Intracoronary radionuclide therapy with liquid 188Re-filled balloons; radiopharmaceutical and dosimetric studies

Percutaneous transluminal coronary angioplasty associated with radioactive liquid-filled balloons has demostrated to be useful to inhibit the growth of neointimal tissue. The present study pursued optimizing the relation risk/benefit during a procedure of brachytherapy with 188Re associated to angioplasty. Since the possibility of balloon rupture exists, to increase the security during the treatment different agents such as 188Re-DTPA, 188Re-Citrate and 188Re-EC vs 188ReO4 were evaluated. Dosimetric studies using Mirdose 3, after iv injection to Wistar rats, evaluation of a number of safety requirements in order to estimate radiation dose delivered to operating personnel and absorbed doses estimated by Monte Carlo method (PENELOPE). It is a safe procedure, both for the patient and the working staff; in case of ballon rupture the use of the above mentioned radiopharmaceuticals increases its security. 188Re beta emitor achieves a local dosis, diminishing the dose in healthy tissue.

188Re-labeled herceptin inhibits proliferation of breast cancer cell line SKBR-3 in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory effects of (188)Re-labeled herceptin on the proliferation in vitro of breast carcinoma cell line (SKBR-3) overexpressing HER-2/neu proto-oncogene.</p><p><b>METHODS</b>Herceptin was radiolabeled with (188)Re through a direct labeling method. SKBR-3 cells were cultured with (188)Re-Herceptin at different radioactivity doses (3.7x10(4), 18.5x10(4), 37x10(4), 55.5x10(4) and 74x10(4) Bq/ml) or with (188)Re-nmIgG and (188)ReO(4)(-) for comparison. The cell proliferation inhibition was determined with MTT colorimetric assay.</p><p><b>RESULTS</b>(188)Re-Herceptin could markedly inhibit the growth of SKBR-3 cells in a radioactivity dose-dependent fashion, while the effect of (188)Re-nmIgG and (188)ReO(4)(-) showed rather poor inhibitory effect in vitro. The 50% inhibition doses (IC(50)) of (188)Re-Herceptin, (188)Re-nmIgG and (188)ReO(4)(-) were 76.1x10(4) Bq/L, 139.2x10(4) Bq/L and 175x10(4) Bq/L, respectively.</p><p><b>CONCLUSION</b>(188)Re-Herceptin can effectively inhibit the growth of in vitro cultured breast cancer cells overexpressing HER-2/neu, and shows much potential for clinical use in beast cancer radioimmunotherapy.</p>

Efficacy of 188Re-herceptin radioimmunotherapy in nude mouse model of nasopharyngeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the effect of radioimmunotherapy with (188)Re-labeled herceptin in nude mice bearing nasopharyngeal carcinoma expressing HER2/neu proto-oncogene and explore the feasibility of (188)Re-herceptin for use as a chemical therapeutic and radioimmunotherapeutic agent.</p><p><b>METHODS</b>A direct radiolabeling method was used to prepare (188)Re-Herceptin. Thirty-two nude mice bearing nasopharyngeal carcinoma were randomized into 4 groups (n=8) to receive single intravenous injection of (188)Re-Herceptin, intratumoral injection of (188)Re-Herceptin, (188)Re-nmIgG and (188)Re, respectively, all at the equivalent dose of 11.1 MBq (50 microl). Another 5 tumor-bearing mice received only intratumoral injection of 50 microl normal saline to serve as the control group. Two days after the injections, 3 mice were selected from each group (except for the control group) for biodistribution observation, and the rest mice were monitored for 4 consecutive weeks for tumor volume changes. Pathological examination of the tumor tissues was also performed.</p><p><b>RESULTS</b>The radioactivity uptake in the tumor was significantly greater whereas normal organ uptake significantly lower in the nude mice receiving intratumoral (188)Re-Herceptin injection than in those with intravenous (188)Re-Herceptin injection (11.53%ID/g vs 2.79%ID/g at 48 h). Intratumoral (188)Re-Herceptin injection caused greater inhibition of tumor growth at the 4th week as compared to the intravenous administration.</p><p><b>CONCLUSION</b>Intratumoral (188)Re-Herceptin administration can significantly inhibit the development of nasopharyngeal carcinoma in mice, and may potentially serve as a new clinical option of regional therapy for treating nasopharyngeal carcinoma overexpressing HER2/neu.</p>

Clinical value of combined therapy with 188Re-HEDP and pamidronate in breast cancer with bone metastasis / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To evaluate the clinical therapeutic value of (188)Re-HEDP combined with pamidronate in breast cancer with bone metastasis.</p><p><b>METHODS</b>Forty-eight patients with breast cancer with multi-bone metastases were randomly divided into three groups:15 patients received (188)Re-HEDP (group A), 15 patients received pamidronate (group B) and 18 patients were treated by (188)Re-HEDP plus pamidronate (group C).</p><p><b>RESULTS</b>The overall pain relief rate was 73.3%, 80.0%, 100.0% in groups A, B and C. The response rate of bone metastasis was 40.0%, 33.3%, 66.7% in groups A, B and C respectively. The therapeutic effect of group C was better than those of groups A and B (P < 0.05), without any significance in the difference (P > 0.05).</p><p><b>CONCLUSION</b>The therapeutic effect of (188)Re-HEDP combined with pamidronate for breast cancer with bone metastasis is remarkable in bone pain relief and bone metastasis control, which is better than either (188)Re-HEDP or pamidronate alone.</p>

Tratamiento de lesiones hepáticas tumorales con RENIO188- LIPIODOL. Experiencia en Colombia / Treatment of liver cancer injuries with RENIO188- LIPIODOL. Experience in Colombia

Objetivo: Evaluar pacientes con lesiones tumorales hepáticas, no quirúrgicas, a quienes se les administro Renio 188 -Lipiodol vía transarterial, como alternativa terapéutica.Método: Once pacientes con cáncer de hígado no operable se trataron con dosis entre 170 y 4181 MBq de Renio 188 Lipiodol a través de la arteria hepática. Los pacientes fueron evaluados clínicamente, con test hematológicos, de función hepática y TAC hepático periódicamente.Resultados: El tratamiento con Renio 188 Lipiodol fue bien tolerado . Tres pacientes desarrollaron fiebre leve y un paciente Neumonitis Intersticial que resolvió completamente. En el TAC de control siete pacientes evidenciaron reducción significativa del tamaño de la lesión , 1 sin cambios, 1 progresión y 2 no se han evaluado.Conclusiones: Renio 188 Lipiodol es un tratamiento seguro, la técnica de preparación fácilmente reproducible y se constituye en una alternativa terapéutica para este tipo de pacientes.

Long-term clinical outcomes of newly implanted stents during intracoronary radiation / 대한내과학회지

BACKGROUND: New stent implantation during intracoronary brachytherapy is discouraged due to the high risk of late thrombosis. However, new stent implantation is inevitable in some cases due to the inadequate ballooning or major dissections. Long-term follow-up results of newly implanted stents during brachytherapy are not well-known. We performed this study to evaluate the long-term clinical outcomes of newly implanted stents during intracoronary brachytherapy. METHODS: In the Seoul national university Post-Angioplasty RhEnium irradiation (SPARE) trial, patients were treated with conventional catheter-based technique and then randomized to either beta- radiation (RG) or control group (CG). Radiation was performed with 188 -rhenium-filled conventional balloon catheter system. From 1999 to 2001, new stent implantation was performed in 58 and 56 patients in RG and CG, respectively. Clinical and angiographic follow up data were analyzed. RESULTS: In RG, short-term angiographic restenosis rate was lower than CG (28.6% vs 53%, p=0.03). In RG, late thrombosis was found in 3 patients. However, there was no late thrombosis in CG. Two year major cardiac event rates were not different between the 2 groups (RG: 25.9% vs CG: 28.3%). Independent predictors for major cardiac event in RG were major dissections (>or=type C) after stent implantation (beta=70, p=0.01) and longer administration of dual antiplatelets (aspirin+clopidogrel/ ticlopidine, >6 months, beta=0.07, p=0.04). CONCLUSION: Stenting during intracoronary brachytherapy seems to be ineffective in reducing long-term event rates. When new stent implantation is inevitable during brachytherapy, extreme attention is required not to make a dissection and long-term dual antiplatelet treatment should be followed after stent implantation.

Intratumoral Injection of (188)Re labeled Cationic Polyethylenimine Conjugates: A Preliminary Report

(188)Re(Rhenium) is easily obtained from an in-house (188)W/(188)Re generator that is similar to the current (99)Mo/(99m)Tc generator, making it very convenient for clinical use. This characteristic makes this radionuclide a promising candidate as a therapeutic agent. Polyethylenimine (PEI) is a cationic polymer and has been used as a gene delivery vector. Positively charged materials interact with cellular blood components, vascular endothelium, and plasma proteins. In this study, the authors investigated whether intratumoral injection of (188)Re labeled transferrin (Tf)-PEI conjugates exert the effect of radionuclide therapy against the tumor cells. When the diameters of the Ramos lymphoma (human Burkitt's lymphoma) xenografted tumors reached approximately 1 cm, 3 kinds of (188)Re bound compounds (HYNIC-PEI-Tf, HYNIC-PEI, (188)Re perrhenate) were injected directly into the tumors. There were increases in the retention of (188)Re inside the tumor when PEI was incorporated with (188)Re compared to the use of free 188Re. The (188)Re HYNIC-Tf-PEI showed the most retention inside the tumor (retention rate=approximately 97%). H&E stain of isolated tumor tissues showed that (188)Re labeled HYNIC-PEI-Tf caused extensive tumor necrosis. These results support (188)Re HYNIC-PEI-Tf as being a useful radiopharmaceutical agent to treat tumors when delievered by intratumoral injection.

Long-Term Follow-Up Results of Intracoronary Beta-Radiation Therapy with a Rhenium-188 Diethylene Triamine Penta-Acetic Acid-Filled Balloon

BACKGROUND AND OBJECTIVES: Intracoronary irradiation has emerged as a successful intervention for the treatment of restenosis. However, the radiation process is complex, difficult and hard to perform. On the contrary, intracoronary radiation therapy using a 188Re-DTPA-filled balloon system is simple and inexpensive. The short-term follow-up results of this system have been reported, but the long-term results remain to be elucidated. The object of this study is to evaluate the short and long-term follow-up results of intracoronary radiation using a 188ReDTPA-filled balloon system in restenotic lesions. SUBJECTS AND METHODS: Thirty-eight patients, with restenotic lesion after previous percutaneous coronary intervention, were selected from the SPARE trial (Seoul National University Post-Angioplasty RhEnium irradiation trial). There were 27 cases in the irradiation group, with 11 in the control group. Irradiation was performed in the restenotic lesions after successful interventions. The results of 6-month angiographic and 6-month and 3-year clinical follow-up data were compared between the two groups. RESULTS: A 6-month angiographic follow-up was performed in 33 patients (87%), 25 in the radiation group and 8 in control. Binary restenosis developed in 1 of 25 (4%) and 4 of 8 (50%) in the radiation and control groups, respectively (p=0.008). At the 6-month clinical follow-up, there were no significant differences in the event rates between the two groups. At the 3-year clinical follow-up, there was a significant difference in the target vessel revascularization: 2 of 27 (7.4%) and 5 of 11 (45.4%) in the radiation and control groups, respectively (p=0.017). There were no deaths or myocardial infarctions. CONCLUSION: Radiation therapy using a 188ReDTPA-filled balloon system is feasible, and may be effective in improving the long-term outcomes in restenotic lesions.

Angioplastia transluminal coronaria asociada a radiación con 188Re. Primer caso de radiación intracoronaria en Uruguay / Transluminal coronary angioplasty associated with 188Re radiation. First case of intracoronary radiation in Uruguay

La restenosis luego de una angioplastia transluminal coronaria exitosa es uno de los problemas más preocupantes en el área de la cardiología intervencionista. Uno de los métodos que se han desarrollado para la prevención y el tratamiento de esta restenosis es la radiación intracoronaria. Se reporta el primer caso tratado en Uruguay con radiación intracoronaria mediante la aplicación de un balón con 188Re. Entre las ventajas que tendría este método sobre otros de radiación intracoronaria se destacan su bajo costo y la facilidad de su aplicación, sin requerir dispositivos costosos ni infraestructura sofisticada de radioprotección. La experiencia acumulada con esta nueva técnica muestra que es un procedimiento factible y seguro. Debe aguardarse más información acerca de la eficacia del mismo en la evolución alejada.

Study of radiation synovectomy using (188)Re-Sulfide in hemophilic arthritis / 中华血液学杂志

<p><b>OBJECTIVE</b>To study the effectiveness of radiation synovectomy with (188)Re-sulfide.</p><p><b>METHODS</b>Twenty rabbit models of joint synovitis were injected intra-articularly with different doses of (188)Re-sulfide from 7.4 to 37.0 MBq. By pathological examination, the effects of (188)Re-sulfide on synovium and cartilage were evaluated. Clinically, 10 joints of 7 cases of hemophilic arthritis with (188)Re-sulfide radiation synovectomy were performed. MRI was taken before and after the synovectomy to evaluate the treatment effects.</p><p><b>RESULTS</b>In rabbit models, when (188)Re-sulfide dose larger than 14.8 MBq, the radiation effect on synovitis was remarkable, including thinning the thickened synovium and reducing the inflammatory cells. When radio-activity dose increased to 37.0 MBq, pathological damage was noted in cartilage. Clinical trial demonstrated that radiation synovectomy by (188)Re-sulfide could reduce the frequencies of intra-articular hemorrhage. MRI showed that edema and villi reduced.</p><p><b>CONCLUSIONS</b>Radiation synovectomy using (188)Re-sulfide is effective on synovitis in hemophilic arthritis.</p>

Evaluation of efficacy and toxicity of 186RE-HEDP in palliation of breast cancer painful bone metastases

This study included 20 female, breast cancer patients with painful bone metastases, presented to Radiation Oncology Department and Nuclear Medicine Unit, Assiut University Hospital, Faculty of Medicine, Assiut University in the period from July 1999 to April 2001. Their mean age was 46.7 years [range 32-61 years]. They were evaluated consecutively, for the efficacy of 186Re-hydroxyethylidene diphosphonate [HEDP] on pain from bone metastases and the toxicity of this agent. 30 mCi of 186Re-HEDP was intravenously administered for each patient, after performing a baseline bone scan with 99mTc-MDP, followed by 24-hour bone scan with the injected rhenium agent. All patients were followed up bi-weekly in the first month then monthly by clinical and laboratory assessment up to three months. Bone scan with 99mTc-MDP was repeated on day 45 and day 90 for evaluation of bone metastases. The results revealed that 19 patients were evaluated for response [one patient was excluded due to acute evolution of her disease and receiving chemotherapy during the period of response assessment]. An objective response was observed in 78.9% of patients with a mean duration of 58 days, nine patients [47.4%] were relieved of pain during the second week and another six patients [31.5%] enjoyed pain relief during the third week; while, the rest of patients [21.1%] continued complaining of pain, three patients [15.7%] without increase intensity, and one patient [5.3%] with increased pain intensity. No major adverse effects were observed. Marrow toxicity did not exceed grade II for white blood cells and grade III for platelets using National Cancer Institute criteria. In conclusion, 186Re-HEDP provides safe symptomatic relief of pain for bone metastases of breast cancer with correctable minimal adverse effects

Radiotherapy with (186)Re-lipiodol II for primary liver cancer patients / 中华外科杂志

<p><b>OBJECTIVE</b>To analyze the biodistribution of (186)Re-lipiodol (RL) in patients with primary liver cancer (PLC) after hepatic arterial injection in attempt to assess the potential of RL as a radiopharmaceutical for the treatment of PLC.</p><p><b>METHODS</b>RL was synthesized from (186)Rhenium and Lipiodol by a series of physical and chemical procedures. Doses of RL ranged from 1 110 MBq to 2 220 MBq per patient depending on the volume of tumor. Quantitative gamma camera imaging (ECT) and gamma counting of serum and urine were used to obtain data for dosimetry estimation. Serum tumor marker (AFP) level and shrinkage of tumor were used to evaluate the therapeutic efficacy of RL.</p><p><b>RESULTS</b>In the hepatic tumor, RL was selectively retained and radioactivity was very high throughout this study. The ratio of tumor concentration to the normal liver tissue concentration (T/NT ratio) was 10 - 14 at 48 hours after injection of RL. The main side effects of this therapy were transient fever and anorexia. No unacceptable toxicity was observed. In 100% of the patients, the therapy resulted in a significant decrease of AFP level and reduction of tumor volume.</p><p><b>CONCLUSION</b>The biodistribution and imaging results demonstrated RL localized selectively in tumor, and that RL may be a potential internal radiopharmaceutical agent for the treatment of primary liver cancer.</p>

Treatment of metastaic bone pain with rhenium-188 hydroxyethylidene diphosphonate

This study was designed to evaluate the safety and effectiveness of rhenium-188 hydroxyethylidene diphosphonate [188Re-HEDP] in patients with skeletal metastases. Thirty-two patient volunteers with cancer metastasized to bone were included in this study. All patients underwent bone scanning with technetium-99m methylene diphosphonate 2 days before the administration of 188Re-HEDP. A dose of 1,110 MBq [30 mCi] of 188Re-HEDP was injected intravenously and whole body dynamic scans were obtained 1, 2, 3, and 5 days later. Blood and urine samples were collected daily for 5 days and then weekly for 4 weeks. The biokinetic data were obtained and the radiation doses were calculated. The reactions, toxicity and pain relief were corrected. No acute reaction or toxicity was evident. Leukopenia was found only in 1 patient with skeletal metastases from prostate cancer. The baseline white blood cell count of 4.3 ' 109/l [normal range 4.0-10.0] declined to a value of 3.0 ' 109/l 1 week after receiving 1,110 MBq [30 mCi] of 188Re-HEDP. The white blood cell count had returned to the baseline category by 4 weeks after injection. No patient was found to be thrombocytopenic. The hemoglobin concentration remained at the baseline level for 6 weeks. The excretion rate of 188Re-HEDP in the urine was 62% of the administered activity during the first 2 days. Twenty-eight of the 32 patients [87.5%] were able to reduce their analgesic intake. Twenty of the 32 patients [62.5%] had a significant improvement in the quality of life while 8 patients [25%] had a minor improvement. Most of the patients experienced an improvement in the quality of life without induction of serious bone marrow reduction with this treatment regime. It is therefore concluded that the use of 188Re-HEDP for treatment of skeletal metastasis appears to be feasible

Evalution of efficacy and toxicity of treatment using rhenium-186 HEDP in metastatic bone disease

To assess the efficacy and toxicity of rhenium-186 HEDP in treating metastases. Patients: Twenty-six patients with bone pain from metastatic cancer were treated with 35 mCi of 186Re HEDP administered intravenously in the outpatient clinic. Patients were followed with pain diaries, records of medication, morbidity, sleep patterns, serial bone scans and a Karnofsky index. Twenty-five patients with complete records were evaluated. Patients were grouped according to the extent of bone metastases as seen in the bone scans. Sixteen patients [64%] showed clinical responses of which 4 became completely pain-free. Pain relief typically began 10-20 days after 186Re HEDP was administered, while maximum benefit was normally achieved by 6 weeks. Relief of pain was maintained for 4-15 months [mean 6 months]. No immediate adverse reactions were observed following the administration of 186Re HEDP. Only a mild transient fall in platelet levels was noted, which normalized by 6 weeks. 186RE HEDP appears as a safe, convenient and an effective palliative for pain secondary to bone metastases in cancer patients