Pain Outcomes in Patients with Metastatic Castration-Resistant Prostate Cancer Treated with 223Ra: PARABO, a Prospective, Noninterventional Study.

223Ra, a targeted α-therapy, is approved for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC) who have bone metastases. In the phase 3 ALSYMPCA study, 223Ra prolonged survival and improved quality of life versus placebo. Our real-world study, PARABO, investigated pain and bone pain-related quality of life in patients with mCRPC and symptomatic bone metastases receiving 223Ra in clinical practice. Methods: PARABO was a prospective, observational, noninterventional single-arm study conducted in nuclear medicine centers across Germany (NCT02398526). The primary endpoint was a clinically meaningful pain response (≥2-point improvement from baseline for the worst-pain item score in the Brief Pain Inventory-Short Form). Results: The analysis included 354 patients, who received a median of 6 223Ra injections (range, 1-6). Sixty-seven percent (236/354) received 5-6 injections, and 33% (118/354) received 1-4 injections. Of 216 patients with a baseline worst-pain score of more than 1, 59% (128) had a clinically meaningful pain response during treatment. Corresponding rates were 67% (range, 98/146) with 5-6 223Ra injections versus 43% (range, 30/70) with 1-4 injections, 60% (range, 60/100) in patients with no more than 20 lesions versus 59% (range, 65/111) in those with more than 20 lesions, and 65% (range, 69/106) in patients without prior or concomitant opioid use versus 54% (range, 59/110) in those with prior or concomitant opioid use. Mean subscale scores (pain severity and pain interference) on the Brief Pain Inventory-Short Form improved during treatment. Conclusion: 223Ra reduced pain in patients with mCRPC and symptomatic bone metastases, particularly in patients who received 5-6 injections. The extent of metastatic disease did not impact pain response.

Efficacy of radiosynovectomy in rheumatoid arthritis.

In this retrospective study, we evaluated the effect of radiosynovectomy of patients with rheumatoid arthritis. Radiosynovectomy was performed in 577 joints of 137 rheumatoid patients. We applied 185 MBq yttrium-90 in knees (n = 58), 74-111 MBq rhenium-186 colloids in ankle (n = 50), wrists (n = 43) and shoulders (n = 35), and 15 to 37 MBq in finger (n = 298) and toe joints (n = 46). The effect of radiosynovectomy was scored in 4 subjective categories: excellent response (no symptoms); good response (significant reduction of symptoms); moderate response (slight decrease); and bad response (no change or worsening), of pain and/or swelling in treated joint 3 months after the procedure. Excellent or good response was observed in 57% of treated knees, 63% of shoulders, 60% of wrists, 64% of ankles, 54% of thumb bases, 55% of MCP's, 54% of PIP's, 53% of DIP's, and 54% of MTP's. Side effects associated to the RSO, i.e., swelling or transient increase of pain, were recorded in 7% of the patients that resolved within 1 month. No patient had any non-reversible skin alteration after treatment, only slight erythema was observed in 5 patients. Radiosynovectomy is effective and safe in the treatment of rheumatoid arthritis.

Tc-99m-PSMA-SPECT/CT Is Superior to Tc-99m-MDP-SPECT/CT in the Staging of Prostatic Cancer with Osseous Metastases after External Beam Radiotherapy.

In the reported patient with advanced prostate cancer, a bone scan showed a false positive finding in thoracic vertebrae bone metastasis after external beam radiotherapy 2 months ago. An additional Tc-99m-prostate-specific membrane antigen scan showed a negative finding, although nonirradiated iliac bone metastasis was concordantly positive in both scans. The decrease in prostate-specific antigen-level from 156.6 ng/mL to 2.3 ng/mL indicates a strong effect of treatment, hence supporting false positivity in bone scan by flare phenomenon.

Radiosynovectomy is effective in thumb basal joint arthritis.

OBJECTIVE: Radiosynovectomy (RSO) describes the internal low-dose radiotherapy of the synovia via intra-articular administration of small radioactive particles. Since the introduction of biologics, the main aetiology of arthritic joints for RSO changed to mostly osteoarthritis with concordant change in typically affected joints. Thus, the effect of RSO in thumb basal joint arthritis (BJTh) with focus on osteoarthritis needs to be explored. DESIGN: From 2017 to 2020, 219 BJTh were treated in 125 patients, 17 patients with rheumatoid arthritis (RA) and 108 patients with osteoarthritis (OA). The therapeutic effect was assessed using a four-step subjective scoring. RESULTS: 20% of the treated joints were symptom free, 48% had a very good response, 16% slight and 16% no response. RSO was performed in 71 patients singularly and in 54 patients repetitively. The mean response duration was 6.8 months with a maximum of 48 months. 35% of patients had post-therapeutic pain relief followed by relapse after 3 months. Response duration showed no significant difference the between first and repetitive therapy, primary responder and primary non-responder and RA and OA. CONCLUSION: In thumb basal joint arthritis, RSO leads to response rates from 66 to 79%, mean response duration from 6 to 12 months and individual response duration 48 months. The present results are in line with previously published response rates in smaller joints. In respect to 35% of patients with relapse within 3 months post-therapy, we recommend a primary follow-up after 3-4 months.

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.

Radiosynoviorthesis (RSO): influencing factors and therapy monitoring.

OBJECTIVE: To evaluate the effectiveness of radiosynoviorthesis (RSO) in relation to joint type and underlying disease by both self-assessment of patients and scintigraphic assessment to determine conditions under which RSO might be preferable to the sole intra-articular corticoid injection. METHODS: Radiosynoviorthesis was performed on 136 patients for 424 joints [242 small, 130 medium-sized, and 52 large joints; 313 with rheumatoid arthritis (RA) and 111 with osteoarthritis (OA)]. The success of RSO was evaluated after 12 months by patients' estimation, and in 35 patients for 157 joints additionally by two-phase bone scintigraphy. The relative change in the scintigraphic uptake was compared with the patients' estimation. RESULTS: The subjectively estimated success rates for the small, medium-sized, and large joints were 89% (215/242), 86% (112/130), and 79% (41/52), and for RA and OA 89% (280/313) and 79% (88/111), respectively. The scintigraphically determined response rates for small and medium-sized joints were 81% (86/106) and 69% (35/51), respectively. There was a mismatch between patients' assessment and scintigraphic assessments in 18% (28/157) with 6 false-negative and 22 false-positive estimations using scintigraphy as the standard of reference. CONCLUSIONS: The success of RSO is higher in patients with RA than in patients with OA. For the finger, ankle, and wrist joints in RA, RSO is so promising that we would like to advocate its preference over the sole intraarticular corticoid injection. Perfusion bone scintigraphy can be used for therapy monitoring and earlier switching to RSO by showing that other therapies have failed.

188Re-HEDP therapy in the therapy of painful bone metastases.

For bone-targeted radionuclide therapy (BTRT), different commercial radiopharmaceuticals are available such as strontium-89, 186Rhenium-hydroxyethylidene diphosphonate (186Re-HEDP), Samarium-153-ethylenediamine tetramethylene phosphonic acid, and radium-223. Unfortunately, the commercial available radiopharmaceuticals are very expensive (from 1,200 to 36,000€ per patient in Europe). The 188W/188Re generator is an ideal source for the long-term (4-6 months) continuous availability of 188Re suitable for the preparation of radiopharmaceuticals for different radionuclide therapies. Labeling at HEDP, it can use cost-effective for BTRT, if enough patients are available for therapy. And so, 188Re-HEDP is the ideal candidate in developing countries which high population to replace the other agents. Two German groups documented a response rate of 80% without any severe side effects and similar bone marrow toxicity compared to the other compounds for 188Re-HEDP. Using 188Re-HEDP in repeated treatments, a prolonged overall survival of repeated to single application was observed (from 4.5 months for single to 15.7 months using ≥≥3 applications).

99mTc-Hynic-TOC imaging in the diagnostic of neuroendocrine tumors.

The aim of this study was to assess the potential of 99mTc-Hynic-TOC imaging in the primary diagnosis and follow-up of midgut neuroendocrine tumors (NETs). In comparison to 111In-octreotide, 99mTc-Hynic-TOC has a higher imaging quality and leads to a lower radiation absorption in patients. 99mTc-Hynic-TOC was used for assessing primary diagnosis (n = 14) and during follow-up (n = 17) in patients with NETs. The scintigraphic findings were compared with computed tomography scans and follow-up. In 31 patients, 34 somatostatin receptor scans using 99mTc-Hynic-TOC were performed. The primary diagnoses were midgut NET. The scintigraphy was true positive in 17 patients, true negative in 9, false negative in 4, and false positive in 1. From these data, a sensitivity of 81%, specificity of 90%, positive predictive value of 94%, and negative predictive value of 69% were calculated. In summary, 99mTc-TOC represents a useful radiotracer in imaging SSTR-expressing tumor lesions with slightly higher sensitivity, higher imaging quality, and lower radiation exposure for patients compared to 111In-octreotide. A 1-day double-acquisition protocol should be used to reduce false-positive findings of the gut.

Radiosynoviorthesis of acromioclavicular joint using 169Er-citrate: prospective evaluation of efficacy.

BACKGROUND: There is a clinical need for therapeutic alternative in patients with persisting painful arthritis of AC-joint and failure of previous treatments. However, no radiopharmaceutical is currently explicitly approved for radiosynoviorthesis of acromioclavicular joint. The aim of our study was to prospectively assess the efficacy and safety of radiosynoviorthesis of acromioclavicular joint using erbium-169 citrate. MATERIAL AND METHODS: Radiosynoviorthesis of acromioclavicular joint was performed in 51 consecutive patients (18 males, 33 females) mean age 64.3 (range 43.8-82.6, median 63.6) years with clinically confirmed arthritis of 85 acromioclavicular joints. The efficacy of RSO was reported by patients according to 10-step visual analogue scale of pain (VAS) (0 = no pain, 10 = most severe pain) at 6 months after radiosynoviorthesis and by ranking the global therapeutic effect of RSO in 4 categories (1 = the best effect, 4 = no change). To assess the variation of blood perfusion in treated joints, the efficacy of RSO was also evaluated by variation of target (acromioclavicular joint)/non-target (soft tissue) uptake ratio (T/NTR) of metylendiphosphonate (99mTc) measured as number of counts over region of interest on blood pool phase of two-phase bone scintigraphy performed before and 6 months after RSO. RESULTS: Radiosynoviorthesis was followed by significant decrease in VAS, mean - 3.1 (-47%). Excellent, good, moderate and bad response was observed in 57 (67%), 25 (29%), 1 (1%) and in 2 (2%) of acromioclavicular joints respectively. A significant correlation between decrease of T/NTR and variation of VAS in % (ρ = 0.532, p < 0.0001) and between T/NTR and subjective evaluation of therapeutic effect in scale 1-4 (ρ = 0.388, p = 0.0002) was observed. However, it was not possible to identify the cut-off value of relative decrease in T/NTR showing sufficient sensitivity and specificity to detect the therapeutic response. CONCLUSION: Results of this prospective study permit to conclude a good efficacy and safety of radiosynoviorthesis using erbium-169 citrate in a series of patients with arthritis of acromioclavicular joint in whom previous line(s) of treatment did not lead to satisfactory pain relief.

Feasibility of high activity rhenium-188-microsphere in hepatic radioembolization.

BACKGROUND: This paper describes the feasibility of intra-arterial high-activity administration of (188)Re-microspheres. METHODS: Patients with unresectable colorectal liver metastases or hepatocellular cancer (HCC) received single treatments with (188)Re-microspheres. The administered activity was calculated to give a liver dose of 100 Gy. From post-therapeutic scans and urine sampling, the dose to the liver, metastases and bladder was calculated. Toxicity was assessed up to 3 months after administration by means of the Common Terminology Criteria for Adverse Events v3.0 (Trotti et al. CTCAE v3.0: development of a comprehensive grading system for the adverse effects of cancer treatment. Semin Radiat Oncol 2003;13(3):176-81). Response was evaluated on CT. RESULTS: 13.6 +/- 4.7 GBq (188)Re-microspheres was administered selective in the feeding artery of the tumour to 10 patients (3 x HCC and 7 x colorectal liver metastases). There was a low urinary excretion rate of 8.9 +/- 3.8% of administered activity within 96 h. The absorbed dose to the tumour, normal liver (excluding the tumour) and bladder was 10.24 +/- 5.02 Gy/GBq (128 +/- 47 Gy), 3.94 +/- 2.52 Gy/GBq (50 +/- 33 Gy) and 0.27 +/- 0.20 Gy/GBq (2.4 +/- 1.9 Gy), respectively. There was an acceptable rate of toxicity in 30% of grades I and II, respectively, and 10% with grade III. There was reversible in the most patients within 14 days after treatment. The response was assessed on CT: two patients had a partial response (PR), five patients had stable disease and three patients had disease progression. CONCLUSION: Treatment of colorectal liver metastases or HCC using high activities of (188)Re-microspheres was well tolerated and a PR was seen in 2 of 10 patients. The treatment represents a therapeutic option in these patients.

A comparative study of 188Re-HEDP, 186Re-HEDP, 153Sm-EDTMP and 89Sr in the treatment of painful skeletal metastases.

AIM: The surface bone-seeking radiopharmaceuticals 188Re-HEDP, 186Re-HEDP and 153Sm-EDTMP, and the volume seeker 89Sr were investigated to determine the efficacy and toxicity in pain palliation of bone metastases. METHOD: The effect of treatment with 188Re-HEDP, 186Re-HEDP, 153Sm-EDTMP and 89Sr on pain symptoms, quality of life, and bone marrow function were studied. In total, 79 patients (18 with breast cancer and 61 with prostate cancer) were treated (31 patients with 188Re-HEDP, 15 patients each with 186Re-HEDP and 153Sm-EDTMP, and 18 patients with 89Sr). All patients were interviewed using standardized sets of questions before and after therapy weekly for 12 weeks. Blood counts were taken weekly for 6 weeks and after 12 weeks. RESULTS: In total, 73% of patients reported pain relief (77% after 188Re-HEDP, 67% after 186Re-HEDP 73% after 153Sm-EDTMP, and 72% after 89Sr). Fifteen percent of patients could discontinue their analgesics and were pain-free. Pain showed a decrease from 3.6+/-1.7 to a maximum of 2.2+/-1.8 at visual analogue scale in 10 steps (P<0.01). Patients described an improvement on the Karnofsky performance scale from 70+/-10% to 78+/-14% 12 weeks after treatment (P=0.15). There were eight patients with a thrombocytopenia grade I, two patients with grade II and one with grade III. The maximum nadir of platelet and leukocyte counts were observed between the 2nd to 5th week after treatment and was reversible within 12 weeks. There were no significant differences in pain palliation, Karnofsky performance status (KPS) and bone marrow toxicity between the different radionuclides (P=0.087-0.449). CONCLUSION: All radiopharmaceuticals were effective in pain palliation, without induction of severe side effects or significant differences in therapeutic efficacy or toxicity.

Can renal doppler sonography replace diuretic radionuclide renography in infants with hydronephrosis?

Reliable differentiation between obstructive and non-obstructive hydronephrosis is decisive for the further therapeutic management in infants. The results of renal Doppler sonography were compared with diuretic radionuclide renography and with the follow-up results in 33 patients (range: 21 to 98 days). In Doppler sonography, a resistive index (RI) of > 0.9 was considered to be abnormal in the sense of an obstruction. In diuretic renography, a T1/2 value (time until a 50% decrease in activity in the kidneys was observed after injection of furosemide) of >20 min was appraised as obstructive hydronephrosis. In six patients an obstructive (T1/2 >20 min) and in 27 patients a non-obstructive (T1/2 <20 min) hydronephrosis was found. All patients with obstruction in diuretic renography showed an abnormal RI (>0.9) in Doppler sonography. In addition, all patients with surgery and obstruction in diuretic radionuclide renography showed an improvement in hydronephrosis. However, seven patients had a false-positive result in Doppler sonography. All patients with non-obstruction in diuretic radionuclide renography showed no worsening of hydronephrosis without surgery in the follow-up. We found a RI of 0.84 +/- 0.07 in the non-obstructive group and of 0.96 +/- 0.05 (p = 0.018) in the obstructive group. Doppler sonography showed discrepant results compared to diuretic radionuclide renography and therefore cannot replace this method.

From palliative therapy to prolongation of survival: (223)RaCl2 in the treatment of bone metastases.

Patients with hormone-refractory prostate cancer often have multiple bone metastases. The resulting bone pain is associated with reduced life quality, increased cost of therapy and impairment of overall survival. Trials with bone-targeting ß-emitters have mostly showed an effect on alleviation of bone pain along with prolongation in survival, documented in only a limited number of patients. A randomized phase III trial (ALSYMPCA) using the α-emitter (223)RaCl2 (Xofigo®) showed for the first time, a longer overall survival of 3.6 months in treated patients as a sign of an antitumor effect. The time to first skeletal-related events was also significantly longer in the therapy group compared with placebo. Because of the short range of α-emitter, the bone marrow toxicity of radium therapy is low, and so this radionuclide could also be a candidate for combination with chemotherapy. The elimination of (223)RaCl2 is mainly through the gastrointestinal tract and side effects are mainly in this area. The procedure is similar to treatment with other bone-seeking agents and consists of six administrations of 50 kBq/kg bodyweight Xofigo®, repeated every 4 weeks. At present Xofigo® is only approved for hormone-refractory prostate cancer.

The benefit of bone-seeking radiopharmaceuticals in the treatment of metastatic bone pain.

PURPOSE: The surface bone-seeking radiopharmaceuticals rhenium-188-HEDP (188Re-HEDP) and samarium-153-EDTMP (153Sm-EDTMP) were investigated to determine the efficacy and toxicity in pain palliation in bone metastases. METHOD: The effect of treatment with 188Re-HEDP and 153Sm-EDTMP on pain symptoms, life quality, and bone marrow function were obtained in 46 patients with prostate and breast cancer. There were 31 patients treated with 188Re-HEDP (3194+/-387 MBq) and 15 patients with 153Sm-EDTMP (2940+/-545 MBq). The 188Re-HEDP group included 6 patients and 25 patients, and the 153Sm-EDTMP group 6 patients and 9 patients with breast and prostate cancer, respectively. All patients had an interview using standardized sets of questions before and after therapy for 12 weeks. Blood counts were taken weekly for 6 weeks and after 12 weeks. RESULTS: After treatment with 188Re-HEDP, 77% of patients reported pain relief and 73% after 153Sm-EDTMP. Sixteen percent of the patients treated with 188Re-HEDP and 13% of those given 153Sm-EDTMP could discontinue their analgesics and were pain free. Patients described an improvement on the Karnofsky performance scale from 73+/-7 to 85+/-8% 12 weeks after 188Re-HEDP (p<0.05) and from 68+/-9 to 74+/-9% after 153Sm-EDTMP (p=0.217). Only 3 patients post-188Re-HEDP and 2 patients post-153Sm-EDTMP showed a thrombocytopenia below 100 x 10(3)/microl. The maximum nadir of platelet and leukocyte counts were observed between the second to fourth week after treatment in both and was reversible within 12 weeks. There were no significant differences in pain palliation, Karnofsky performance scale and bone marrow toxicity between the lower beta energy 153Sm-EDTMP and the higher beta energy 188Re-HEDP (p=0.098-0.442). CONCLUSION: Both radiopharmaceuticals were effective in pain palliation, without induction of severe side effects or significant differences in therapeutic efficacy or toxicity.

Systemic radionuclide therapy in pain palliation.

Several radiopharmaceuticals were investigated to determine their efficacy and toxicity in the palliation of painful bone metastases. Data on the influence of rhenium-188 hydroxyethylidene diphosphonate (188Re-HEDP), rhenium-186 hydroxyethylidene diphosphonate (186Re-HEDP), and strontium-89 (89Sr) on pain symptoms, quality of life, and bone-marrow function were obtained in 64 patients with breast and prostate cancer. Thirty-one patients were treated with 188Re-HEDP (3194 +/- 387 MBq), 15 patients with 186Re-HEDP (1358 +/- 158 MBq), and 18 patients with 89Sr (152 +/- 19 MBq). The 188Re-HEDP group included six breast cancer patients and 25 prostate cancer patients; the 186Re-HEDP group included three breast cancer patients and 12 prostate cancer patients; and the 89Sr group included three breast cancer patients and 15 prostate cancer patients. All subjects participated in an interview using a standardized sets of questions before and after the 12-week term of therapy. Blood counts were taken weekly for six weeks and after 12 weeks. Results showed that 77 percent of patients reported pain relief after treatment with 188Re-HEDP, 67 percent after treatment with 186Re-HEDP, and 72 percent after treatment with 89Sr. Sixteen percent of patients treated with 188Re-HEDP, 13 percent treated with 186Re-HEDP, and 17 percent treated with 89Sr were able to discontinue their analgesics and were pain-free. Patients described an improvement on Karnofsky performance status (KPS) from 73 +/- 7 percent to 85 +/- 8 percent 12 weeks after 188Re-HEDP (p < 0. 05), from 72 +/- 13 percent to 79 +/- 12 percent after 186Re-HEDP (p = 0.251), and from 62 +/- 14 percent to 69 +/- 16 percent after 89Sr (p = 0.415). Only three patients undergoing 188Re-HEDP therapy, one undergoing 186Re-HEDP therapy, and three undergoing 89Sr therapy had thrombocytopenia (platelet count below 100 x 10(3)/microl) following treatment. The maximum nadir of platelet and leukocyte counts was observed between the second and fifth week after treatment for all radionuclides and was reversible within 12 weeks. The nadir was earlier for 188Re-HEDP with a shorter physical half-life compared with 89Sr. There were no significant differences in bone marrow toxicity (p = 0.123-0.421). Results of this study indicate that all evaluated radiopharmaceuticals were effective in pain palliation without induction of severe side effects. The increase in KPS after 188Re-HEDP was the only statistically significant finding (p = 0.001).

Radiation protection in radiosynovectomy of the knee.

Radiosynovectomy is a widely available therapeutic option that involves radiopharmaceutical injections into joints to treat rheumatoid arthritis. However, data on the beta-radiation dose equivalents for the staff performing such treatments are limited. The aim of this study was to determine the personal dose equivalents H(P)(0.07) to the skin of the hands of the treating physician under several exposure scenarios. An activity of 185 MBq (90)Y was used. Thermoluminescence detectors were attached at the finger tip of the thumb, forefinger, and middle finger of the treating physician. Measurements of beta-exposures were made during treatment of 70 knees with (90)Y under the following exposure scenarios: group 1, the radiosynovectomy was performed with syringe shield with Perspex (Plexiglas, Röhm GmbH, Germany) (thickness of 5 mm); group 2, additionally a manipulator was used for fixation of the needle; group 3, radiation-resistant gloves were added to the measures in groups 1 and 2. For group 1, the highest beta doses were measured at the forefinger (22.1 microSv MBq(-1)) (22,100 microrem/27 microCi) and thumb with 16.5 microSv MBq(-1) (16,000 microrem/27 microCi) at the left hand, which holds the needle (right-handed physician). In group 2, the radiation doses were reduced to 0.6 microSv MBq(-1) (60 microrem/27 microCi) at the left forefinger and 0.5 microSv MBq(-1) (50 microrem/27 microCi) at the left thumb. The use of a manipulator and special radiation resistant gloves reduced the radiation dose to 0.4 microSv MBq(-1) (40 microrem/27 microCi) at the left forefinger and to 0.3 microSv MBq(-1) (30 microrem/27 microCi) at the left thumb in group 3. It was concluded that while performing radiosynovectomy without a manipulator for fixation of the needle, the dose measured at the left forefinger could exceed the German limit of 500 mSv (50 rem) per year for the official dosimetry at the skin. Using holding forceps allows compliance with the legal limit and could considerably reduce the beta dose. The use of radiation-resistant gloves reduced the beta dose at the skin only slightly.

Dosimetry of 188Re-hydroxyethylidene diphosphonate in human prostate cancer skeletal metastases.

UNLABELLED: 188Re-Hydroxyethylidene diphosphonate ((188)Re-HEDP) was used in previous studies for the palliative treatment of metastatic bone pain. However, the kinetic and radiation-absorbed doses have not been well documented. Therefore, the aim of this study was to gather dosimetric data for (188)Re-HEDP. METHODS: Thirteen prostate cancer patients with skeletal involvement were treated with 2,700-3,459 MBq (mean dose, 3,120 MBq) (188)Re-HEDP. Patients underwent whole-body scans 3, 20, and 28 h after therapy. The effective half-life, residence time, and radiation-absorbed dose values were calculated for the whole body, bone marrow, kidneys, and bladder as well as for 29 bone metastases. The urinary excretion rate was determined in 6 urine samples of each patient collected over 48 h at 8-h intervals beginning immediately after the administration of (188)Re-HEDP. After injection of (188)Re-HEDP, blood samples were taken weekly for 6 wk, and platelet and leukocyte counts were performed. RESULTS: The mean effective half-life was 15.9 +/- 3.5 h in bone metastases, 10.9 +/- 2.1 h in the bone marrow, 11.6 +/- 2.1 h in the whole body, 12.7 +/- 2.2 h in the kidneys, and 7.7 +/- 3.4 h in the bladder. The following radiation-absorbed doses were calculated: 3.83 +/- 2.01 mGy/MBq for bone metastases, 0.61 +/- 0.21 mGy/MBq for the bone marrow, 0.07 +/- 0.02 mGy/MBq for the whole body, 0.71 +/- 0.22 mGy/MBq for the kidneys, and 0.99 +/- 0.18 mGy/MBq for the bladder. (188)Re-HEDP showed a rapid urinary excretion within the first 8 h after therapy, with 41% of the (188)Re-HEDP administered being excreted. Forty-eight hours after therapy, the excretion rate was 60% +/- 12%. Only 1 patient showed a decrease of platelet count below 100 x 10(9) counts/L. None of the patients presented with a decrease of leukocyte count below 3.0 x 10(9) counts/L. CONCLUSION: (188)Re-HEDP is an effective radiopharmaceutical used in the palliative treatment of metastatic bone pain. The radiation-absorbed dose is acceptable for bone pain palliation with low doses for the normal bone marrow and the whole body.

Dose-dependent histological alterations in the rat lung following intravenous application of Re-188-labeled microspheres.

PURPOSE: The objective of this study was to determine the dose-effect correlation of pneumopathy after application of Rhenium-188 microspheres (Re-188 MS) in an animal model using histological changes as an end-point. METHODS AND MATERIALS: Wistar rats received an intravenous injection of Re-188 MS yielding doses that ranged from ˜ 2 to ˜ 55 Gy. Lungs were removed after ˜ 25 weeks and prepared for histology. Sections were evaluated using a semi-quantitative 5-tiered score. Dose groups of 10 Gy intervals were statistically analyzed using the Chi-square test with respect to grade and extent of connective tissue accumulation, thickness of vessel walls and accumulation of alveolar macrophages (AM). RESULTS: There was a statistically significant increase in connective tissue content and extent in all dose groups compared to control lungs and at least between each other dose group. The steepest increase in connective tissue was at doses higher than 40 Gy. Starting from that dose, a statistically significant increase of AM accumulation and vessel wall thickness occurred. CONCLUSIONS: There was a clear dose-effect correlation between radiation dose and histological changes. These findings allow an estimation of potential normal tissue damage especially during tumor treatments of liver lesions with radioactive particles in patients with significant liver-to-lung shunts.