Biological dosimetry after yttrium-90 citrate colloid radiosynoviorthesis

Radiosynoviorthesis (RSO) with the β-particle-emitting nuclide yttrium-90 is an established concept for the treatment of persistent synovitis of the knee joint. The aim of this study was to investigate the biological radiation effect on the basis of a characteristic radiation parameter. Patients, methods: After RSO procedures with yttrium-90 citrate colloid and subsequent immobilisation of the knee, blood specimens of 10 patients were collected immediately before RSO and 11 to 13 days after the intervention. The yield of dicentric chromosomes in the lymphocytes was determined exclusively in metaphases of the first cell cycle in vitro. In addition, activity leakage was measured by wholebody bremsstrahlung-scintigraphy. Results: No statistically significant increase in the number of dicentric chromosomes (26 before treatment and 34 after treatment) in 20 192 cells analyzed from the 20 blood samples could be found as a result of RSO. However, the analysis of at least 1000 cells per blood sample demonstrates a tendency for a biological radiation effect in the blood of patients on the basis of this characteristic radiation parameter. Two of the 10 RSO patients had undergone a second RSO using yttrium- 90 citrate, whereby one patient displayed activity transport out of the knee joint, amounting to 6 MBq. Only for him a radiation effect (about 130 mGy per single RSO) could be calculated by biological dosimetry. Conclusion: Since in general, based on the analysis of dicentric chromosomes in at least 1000 lymphocytes per individual, detection limits for groups of persons after long-term exposures to low-LET radiation of 50-100 mGy are possible, we assume that RSO with yttrium-90 should be associated with a low whole-body radiation exposure.

[99mTc-MIBI scintigraphy of hypofunctional thyroid nodules. Comparison of planar and SPECT imaging]

99mTc-MIBI-scintigraphy allows to assess the dignity of hypofunctional thyroid nodules. A concordant pattern in MIBI- and pertechnetate-scintigraphy excludes malignancy with high accuracy. For increased MIBI-uptake histological evaluation is advised. The assessment of MIBI-isointense nodules is discussed controversially. Objective of our study was to analyse the prevalence of malignancy for isointense nodules and the diagnostic accuracy of image acquisition in SPECT-technique.

PATIENTS, METHODS

MIBI-scintigraphies were analysed retrospectively. Imaging was performed 60 min after intravenous injection of 510 MBq 99mTc-MIBI. Thyroid nodules were assessed as hypo-, iso- or hyperintense compared to the paranodular tissue.

RESULTS

83 of 225 patients underwent thyroid surgery (age 48.6 ± 12.6 years, 72% women). In 12 (14.5%) cases a papillary carcinoma was diagnosed. In planar imaging 12, 34 and 37, in tomographical imaging 16, 21 and 46 nodules, respectively, were classified as hypo-, iso- oder hyperintense. Among hypo-, iso- and hyperintense nodules in planar imaging 1, 5 and 6 carcinomas were found, resp. In tomographical imaging no, 4 and 8 carcinomas were found, respectively. Classification of iso- and hyperintense nodules as "suspicious for malignancy" showed for planar imaging a sensitivity, specificity, NPV and PPV of 91.7, 15.5, 91.7 and 15.6%, for tomographical imaging of 100, 22.5, 100 and 17.9%, respectively.

CONCLUSION

Hypofunctional thyroid nodules with iso- and hyperintense MIBI-Uptake have a comparable prevalence of malignancy. Image acquisition in SPECT-technique results in improved diagnostic sensitivity and negative predictive value.

Thyroiditis de Quervain. Are there predictive factors for long-term hormone-replacement?

BACKGROUND

Subacute thyroiditis is a usually self-limiting disease of the thyroid. However, approximately 0.5-15% of the patients require permanent thyroxine substitution. Aim was to determine predictive factors for the necessity of long-term hormone-replacement (LTH).

PATIENTS, METHODS

We retrospectively reviewed the records of 72 patients with subacute thyroiditis. Morphological and serological parameters as well as type of therapy were tested as predictive factors of consecutive hypothyroidism.

RESULTS

Mean age was 49 ± 11 years, f/m-ratio was 4.5 : 1. Thyroid pain and signs of hyperthyroidism were leading symptoms. Initial subclinical or overt hyperthyroidism was found in 20% and 37%, respectively. Within six months after onset 15% and 1.3% of the patients developed subclinical or overt hypothyroidism, respectively. At latest follow-up 26% were classified as liable to LTH. At onset the thyroid was enlarged in 64%, and at latest follow-up in 8.3%, with a significant reduction of the thyroid volume after three months. At the endpoint the thyroid volume was less in patients in the LTH group compared with the non-LTH group (41.7% vs. 57.2% of sex-adjusted upper norm, p = 0.041). Characteristic ultrasonographic features occurred in 74% of the patients in both lobes. Serological and morphological parameters as well as type of therapy were not related with the need of LTH.

CONCLUSIONS

In this study the proportion of patients who received LTH was 26%. At the endpoint these patients had a lower thyroid volume compared with euthyroid patients. No predictive factors for LTH were found.

Biological dosimetry after radiosynoviorthesis with rhenium-186 sulphide and erbium-169 citrate

Radiosynoviorthesis (RSO) with the nuclides rhenium-186 sulphide (186Re) and erbium-169 citrate (169Er) is an established concept for the treatment of persistent synovitis of medium and small sized joints. THE AIM of the present studies was to investigate the biological radiation effect based on analysing chromosome aberrations.

PATIENTS, METHODS

Immediately before and 17 to 19 days (186Re) or 45 to 50 (169Er) days after RSO with 186Re or 169Er colloid and subsequent immobilisation of the treated joint, blood samples of a total of 23 patients were collected. The yield of dicentric chromosomes in lymphocytes was determined exclusively in metaphases of the first cell cycle in vitro. In addition, for 186Re the activity leakage was measured three days after RSO by whole-body scintigraphy.

RESULTS

No statistically significant increase in the number of dicentric chromosomes (40 and 88 before and 59 and 105 after treatment with 186Re and 169Er, respectively) in a total of 47017 cells analysed from 46 blood samples could be found as a result of RSO. For 186Re an activity leakage of 3.9%±7% with a maximum of 23.4% corresponding to an effective dose of 2.8±4.5 mSv , respectively 13.8 mSv, was determined. Also in the case of the maximum leakage no significant increase of dicentric chromosomes were detected.

CONCLUSIONS

No significant biological radiation effect can be detected after RSO with 186Re and 169Er, also in cases of high leakage. Therefore, RSO can be classified as a save therapeutic procedure without a relevant radiation risk.

Evaluation of aseptic loosening of knee prostheses by quantitative bone scintigraphy

In not infected knee prostheses bone scintigraphy is a possible method to diagnose mechanical loosening, and therefore, to affect treatment regimes in symptomatic patients. However, hitherto studies showed controversial results for the reliability of bone scintigraphy in diagnosing loosened knee prostheses by using asymptomatic control groups. Therefore, the AIM of our study was to optimize the interpretation procedure and to evaluate the accuracy using results from revision surgery as standard.

METHODS

Retrospectively, we were able to examine the tibial component in 31 cemented prostheses. In this prostheses infection was excluded by histological or bacteriological examination during revision surgery. To quantify bone scintigraphy, we used medial and lateral tibial regions with a reference region from the contralateral femur.

RESULTS

To differentiate between loosened and intact prostheses we found a threshold of 5.0 for the maximum tibia to femur ratio of the both tibial regions and a threshold of 18% for the difference of the ratio of both tibial regions. Using these thresholds, values of 0.9, 1, 0.85, 1, and 0.94 were calculated for sensitivity, specificity, negative predictive value, positive predictive value, and accuracy, respectively. To get a sensitivity of 1, we found a lower threshold of 3.3 for the maximum tibia to femur ratio.

CONCLUSION

Quantitative bone scintigraphy appears to be a reliable diagnostic tool for aseptic loosening of knee prostheses with thresholds evaluated by revision surgery results being the golden standard.

Radiosynoviorthesis of medium-sized joints with rhenium-186-sulphide colloid: a review of the literature

Hypertrophy and inflammation of the synovium with various underlying pathologies - such as rheumatoid arthritis, osteoarthritis, haemophilia and spondyloarthropathy - can be treated successfully by radiosynoviorthesis (RSO). For medium-sized joints (shoulder, elbow, wrist, hip and ankle), the radionuclide of choice is rhenium-186. We review the evidence for the efficacy of this local, relatively non-invasive therapy and evaluate its benefits and risks. We conclude good evidence of rhenium-186 RSO in rheumatoid arthritis and haemophilic arthropathy. In the remaining pathologies, up to now, the therapeutic efficacy has not been confirmed by today's most stringent criteria for clinical studies. The available data support rhenium-186 RSO as a suitable second-line treatment for patients in whom other therapies (including locally injected corticoids) have failed, as long as proper attention is paid to correct administration - including post-treatment immobilization and the co-administration of corticoids.

The effect of the beta-emitting yttrium-90 citrate on the dose-response of dicentric chromosomes in human lymphocytes: a basis for biological dosimetry after radiosynoviorthesis

The production of dicentric chromosomes in human lymphocytes by beta-particles of yttrium-90 (Y-90) was studied in vitro to provide a basis of biological dosimetry after radiosynoviorthesis (RSO) of persistent synovitis by intra-articular administration of yttrium-90 citrate colloid. Since the injected colloid may leak into the lymphatic drainage exposing other parts of the body to radiation, the measurement of biological damage induced by beta-particles of Y-90 is important for the assessment of radiation risk to the patients. A linear dose-response relationship (alpha = 0.0229 +/- 0.0028 dicentric chromosomes per cell per gray) was found over the dose range of 0.2176-2.176 Gy. The absorbed doses were calculated for exposure of blood samples to Y-90 activities from 40 to 400 kBq using both Monte Carlo simulation and an analytical model. The maximum low-dose RBE, the RBE(M) which is equivalent to the ratio of the alpha coefficients of the dose-response curves, is well in line with published results obtained earlier for irradiation of blood of the same donor with heavily filtered 220 kV X-rays (3.35 mm copper), but half of the RBE(M) relative to weakly filtered 220 kV X-rays. Therefore, it can be concluded that for estimating an absorbed dose during RSO by the technique of biological dosimetry, in vitro and in vivo data for the same radiation quality are necessary.

[Radiation synovectomy of the knee joint: Evaluation of bremsstrahlung-detection by using a corpse phantom]

AIM

Multiple procedures for the quantification of activity leakage in radiation synovectomy of the knee joint have been described in the literature. We compared these procedures considering the real conditions of dispersion and absorption using a corpse phantom.

METHODS

We simulated different distributions of the activity in the knee joint and a different extra-articular spread into the inguinal lymph nodes. The activity was measured with a gamma-camera. Activity leakage was calculated by measuring the retention in the knee joint only using an anterior view, using the geometric mean of anterior and posterior views, or using the sum of anterior and posterior views. The same procedures were used to quantify the activity leakage by measuring the activity spread into the inguinal lymph nodes. In addition, the influence of scattered rays was evaluated.

RESULTS

For several procedures we found an excellent association with the real activity leakage, shown by an r(2) between 0.97 and 0.98. When the real value of the leakage is needed, e. g. in dosimetric studies, simultaneously measuring of knee activity and activity in the inguinal lymph nodes in anterior and posterior views and calculation of the geometric mean with exclusion of the scatter rays was found to be the procedure of choice.

CONCLUSION

When measuring of activity leakage is used for dosimetric calculations, the above-described procedure should be used. When the real value of the leakage is not necessary, e. g. for comparing different therapeutic modalities, several of the procedures can be considered as being equivalent.

Biological dosimetry after yttrium-90 citrate colloid radiosynoviorthesis

Radiosynoviorthesis (RSO) with the ss-particle-emitting nuclide yttrium-90 is an established concept for the treatment of persistent synovitis of the knee joint. The AIM of this study was to investigate the biological radiation effect on the basis of a characteristic radiation parameter.

PATIENTS, METHODS

After RSO procedures with yttrium-90 citrate colloid and subsequent immobilisation of the knee, blood specimens of 10 patients were collected immediately before RSO and 11 to 13 days after the intervention. The yield of dicentric chromosomes in the lymphocytes was determined exclusively in metaphases of the first cell cycle in vitro. In addition, activity leakage was measured by wholebody bremsstrahlung-scintigraphy.

RESULTS

No statistically significant increase in the number of dicentric chromosomes (26 before treatment and 34 after treatment) in 20 192 cells analyzed from the 20 blood samples could be found as a result of RSO. However, the analysis of at least 1000 cells per blood sample demonstrates a tendency for a biological radiation effect in the blood of patients on the basis of this characteristic radiation parameter. Two of the 10 RSO patients had undergone a second RSO using yttrium-90 citrate, whereby one patient displayed activity transport out of the knee joint, amounting to 6 MBq. Only for him a radiation effect (about 130 mGy per single RSO) could be calculated by biological dosimetry.

CONCLUSION

Since in general, based on the analysis of dicentric chromosomes in at least 1000 lymphocytes per individual, detection limits for groups of persons after long-term exposures to low-LET radiation of 50-100 mGy are possible, we assume that RSO with yttrium-90 should be associated with a low whole-body radiation exposure.

Radiation synovectomy of the knee joint

Aim: Multiple procedures for the quantification of activity leakage in radiation synovectomy of the knee joint have been described in the literature. We compared these procedures considering the real conditions of dispersion and absorption using a corpse phantom. Methods: We simulated different distributions of the activity in the knee joint and a different extra-articular spread into the inguinal lymph nodes. The activity was measured with a gammacamera. Activity leakage was calculated by measuring the retention in the knee joint only using an anterior view, using the geometric mean of anterior and posterior views, or using the sum of anterior and posterior views. The same procedures were used to quantify the activity leakage by measuring the activity spread into the inguinal lymph nodes. In addition, the influence of scattered rays was evaluated. Results: For several procedures we found an excellent association with the real activity leakage, shown by an r² between 0.97 and 0.98. When the real value of the leakage is needed, e. g. in dosimetric studies, simultaneously measuring of knee activity and activity in the inguinal lymph nodes in anterior and posterior views and calculation of the geometric mean with exclusion of the scatter rays was found to be the procedure of choice. Conclusion: When measuring of activity leakage is used for dosimetric calculations, the above-described procedure should be used. When the real value of the leakage is not necessary, e. g. for comparing different therapeutic modalities, several of the procedures can be considered as being equivalent.

Infektdiagnostik nach Knie-TEP-Implantation

AIM

In this study, the accuracy of antigranulocyte scintigraphy as a diagnostic means prior to revision in infected total knee replacement was compared to that of preoperative joint aspiration and laboratory parameters. The most efficient combination of all diagnostic methods was calculated and thus a diagnostic algorithm recommended. The value of PCR was compared to commonly used techniques of microbiological culturing.

METHODS

Preoperative diagnostic means for infection of 50 total knee replacements in 45 patients requiring revision surgery, were retrospectively analyzed. Inclusion criteria were the intraoperative microbiological and histological verification of infection. Sensitivity, specificity, negative and positive prediction value of C-reactive protein (CRP) and leukocytes, antigranulocyte scintigraphy with (99m)Tc-labeled antibodies, and preoperative joint aspiration were calculated. Furthermore, the accuracy of the different techniques of culturing was compared to that of the polymerase chain reaction (PCR) based on the intraoperative histological findings. Two blinded examiners evaluated specimens taken intraoperatively according to the criteria of Mirra.

RESULTS

We observed a sensitivity of 1.0, a specificity of 0.82, a positive prediction value of 0.83 and a negative prediction value of 1.0 for the antigranulocyte scintigraphy. The sensitivity of preoperative joint aspiration was 0.5, the specificity 1.0, and the positive and negative prediction values were 1.0 and 0.5. Correlated to the intraoperative histological findings the accuracy of PCR and culturing was comparable. The highest accuracy was obtained for blood culture samples.

CONCLUSION

Compared to preoperative joint aspiration the antigranulocyte scintigraphy proved to be more sensitive in the diagnosis an infected knee replacement while having a high specificity. An advantage of PCR compared to the common microbiological culturing techniques was not observed.

Stufendiagnostik bei postinfektiöser Hüft- und Knie-TEP-Implantation: Aussagekraft von Laborparametern und Antigranulozytenszintigraphie

AIM

In the case of two-stage infect revision arthroplasties of hip and knee joint, of primary resection arthroplasties and before implantation of arthroplasties after septic arthritis the accuracy of preoperative laboratory parameters and antigranulocyte scintigraphy was analysed. Furthermore, we stained the intraoperatively taken joint synovial samples with hematoxylin-eosin and also with antibodies against human neutrophil elastase in order to investigate if immunohistological examination provides further or different information.

METHOD

In 24 patients with intraoperative verification of infection we calculated sensitivity, specificity, positive and negative predictive values for laboratory tests, antigranulocyte scintigraphy and the most suitable combination of both. The joint synovial samples stained with antibodies against human neutrophil elastase were compared to those stained with hematoxylin-eosin according to the criteria of Mirra.

RESULTS

We observed the best results for the combination of C-reactive protein and antigranulocyte scintigraphy with a sensitivity of 1, a specificity of 0.92, a positive predictive value of 0.75 and a negative predictive value of 1. No additional or different information was observed by the immunohistological stained samples.

CONCLUSION

Stage diagnostic using C-reactive protein and antigranulocyte scintigraphy provides accurate information to assess the status of infection before hip and knee replacement after infect revision. Additional immunohistological staining besides the routinely taken hematoxylin-eosin staining of joint synovial samples is not recommended.

[Staged diagnosis of septic hip endoprosthesis loosening with laboratory parameters and antigranulocyte scintigraphy]

AIM

The value of serial diagnosis of septic loosening of hip endoprosthesis using laboratory parameters and antigranulocytes scintigraphy was investigated and compared to joint aspiration.

METHOD

In 35 patients with intraoperative verification of infection, we calculated sensitivity, specify and prevalence dependent positive and negative predictive values for antigranulocyte scintigraphy, laboratory tests and the most suitable combination of both. We also calculated predictive values of joint aspiration using sensitivity and specify values given in the literature.

RESULTS

From negative and positive predictive values, of the sedimetation rate and leukocyte count provided no increase of information. We found the same result for positive predictive values of C-reactive protein. For antigranulocyte scintigraphy alone, we found a distinct but still unsatisfying increase of information. Nevertheless, in both cases infection could be excluded definitely. Therefore, the combination of C-reactive protein and antigranulocyte scintigraphy was suitable and the positive predictive values of this combination were only about 5% lower than those of joint aspiration. But with joint aspiration, infection could not be excluded.

CONCLUSION

A positive result in serial diagnosis using C-reactive protein and antigranulocyte scintigraphy leads to an distinct increase in the probability of infection which is comparable to that of joint aspiration. The additional advantages of this procedure are the certain exclusion of infection and the absence of invasiveness.

[A patient with Gulf war syndrome. On discussion of an uncertain disease picture]

The Gulf War syndrome represents neurological and neuropsychological disorders in veterans of the Persian Gulf war. Until today, the various symptoms observed could not be attributed to any defined disease. As a possible cause, exposure to neurotoxic agents such as the organophosphates used during the war has been suggested by many authors. We report on a 29-year-old man who suffered from dysmnesia, disturbance of orientation, cognitive impairment, and double vision. His history revealed several front-line operations in 1990 and 1991 during the Gulf War. Physical examinations showed a complex eye-movement disturbance and a horizontal nystagmus, which was neuro-ophthalmologically confirmed. The early auditory potentials referred to a brainstem dysfunction and the cognitive disturbances correlated to changes in the late-appearing component of event-related potentials (P 300). Brain imaging with CCT, MRI, SPECT, PET, and EEG and CSF showed no pathologies. Neuropsychological tests disclosed severe cognitive impairment especially concerning memory. Three-month follow-up studies in a department of psychosomatic medicine excluded a dissociative disorder as a feature of a post-traumatic stress or a conversion disorder. This is the first case of Gulf War syndrome in Germany. We focus on an unfamiliar complication after the war. The recent literature is reviewed.

[Antigranulocyte scintigraphy of septic loosening of hip endoprosthesis: effect of different methods of analysis]

AIM

Diagnosis of infection with help of antigranulocyte scintigraphy near body stem is difficult because of contemporary visualisation of bone marrow. Therefore, we investigated, whether it is possible to improve the accuracy in diagnosing septic loosening of hip endoprosthesis by changing the analyzing methods.

METHODS

In 28 patients, the results of a visual interpretation of late scan, a visual interpretation and a quantitative interpretation of time-activity-course were compared. These results were verified by histology respectively microbiology.

RESULTS

Histological and microbiological verification found 14 septic loosening and 14 aseptic loosening of the hip prothesis. Therefore, sensitivity, specificity, negative and positive predictive value for the visual interpretation of late scan were 0.86, 0.57, 0.80 and 0.67. For visual and quantitative interpretation of time-activity-course we found 0.86, 0.79, 0.85 and 0.80 respectively 1, 0.93, 1, 0.93. For interobserver agreement we found kappa coefficients of 0.28 +/- 0.2 for visual interpretation of late scan, 0.48 +/- 0.17 for visual interpretation and 1.0 +/- 0 for quantitative interpretation of time-activity-course.

CONCLUSION

In all investigated values quantitative interpretation of time-activity-course was superior to the other analyzing methods. Therefore, antigranulocyte scintigraphy for septic loosening of hip endoprosthesis should be interpreted quantitatively.

Comparison of HIG scintigraphy and bloodpool scintigraphy using HDP in arthritic joint disease

AIM

Because of a similar tracer accumulation, we assumed to get the same information about synovitis in arthritic joint disease with HIG scintigraphy and bloodpool scintigraphy using HDP. Therefore, we compared retrospectively 23 patients.

METHODS

In HIG scintigraphy, synovitis was diagnosed according to increasing activity from early to late image. In bloodpool scintigraphy according to an increased activity in comparison to the surrounding tissues.

RESULTS

In 694 joints comparison of both scintigraphic modalities was possible, resulting in a 2 x 2 kappa coefficient of 0.93 or 0.97 by using late-phase bone scintigraphy as an anatomical marker. For intra- and interobserver agreement, 2 x 2 kappa coefficients of 0.93 and 0.88 in HIG scintigraphy, respectively 0.96 and 0.90 in blood-pool scintigraphy were calculated.

CONCLUSION

This study shows an excellent agreement in the visualization of synovitis by HIG and bloodpool scintigraphy. Because of its higher objectivity and lower cost, investigation of synovitis should be performed by bloodpool scintigraphy.

Comparison of HIG Scintigraphy and Bloodpool Scintigraphy Using HDP in Arthritic Joint Disease

Aim: Because of a similar tracer accumulation, we assumed to get the same information about synovitis in arthritic joint disease with HIG scintigraphy and bloodpool scintigraphy using HDP. Therefore, we compared retrospectively 23 patients. Methods: In HIG scintigraphy, synovitis was diagnosed according to increasing activity from early to late image. In bloodpool scintigraphy according to an increased activity in comparison to the surrounding tissues. Results: In 694 joints comparison of both scintigraphic modalities was possible, resulting in a 2 × 2 kappa coefficient of 0.93 or 0.97 by using late-phase bone scintigraphy as an anatomical marker. For intra- and interobserver agreement, 2 × 2 kappa coefficients of 0.93 and 0.88 in HIG scintigraphy, respectively 0.96 and 0.90 in blood-pool scintigraphy were calculated. Conclusion: This study shows an excellent agreement in the visualization of synovitis by HIG and bloodpool scintigraphy. Because of its higher objectivity and lower cost, investigation of synovitis should be performed by bloodpool scintigraphy.

Thyroid disorders in female patients with ankylosing spondylitis

The association between rheumatological and thyroid disorders has long been known, the most common being the association of rheumatoid arthritis and autoimmune thyroiditis. Little is known as to possible thyroid involvement in ankylosing spondylitis (AS). In 22 female patients with AS and 22 healthy age-matched control subjects parameters of thyroid gland function, rheumatic activity, as well as a subtle drug anamnesis of the rheumatic medication, and an ultrasonographic examination of the thyroid gland were determined. Thyroid function was tested by intravenous injection of 400 microg thyrotropin-releasing hormone (TRH). In parallel basal levels of reverse-T3 (rT3), calcium and anti-thyroid antibodies were estimated. In the AS-group an enlarged thyroid volume was seen in 10 cases, basal FT4, FT3 and TT3 were significantly lower, TSH and TT4 were found to be in the normal range and rT3 was significantly increased. The prevalence of anti-thyroid antibodies was significantly higher in the AS-group. The AS-patients responded as well as the controls with thyroid hormone secretion to TRH, within an observation period of 2 hours. No differences were observed in TSH response. Free serum calcium showed in both groups no significant difference. To summarize our results, female patients with AS showed a

[Activity leakage and radiation exposure in radiation synovectomy of the knee: influence of different therapeutic modalities]

In rheumatic diseases, radiation synovectomy is a reliable method. Meanwhile, radiation synovectomy is an outpatient therapy. In addition, combination with arthroscopic synovectomy is an increasing therapeutic modality. In comparison to the hitherto inpatient modality, a greater lymphatic emigration of the radionuclide and, therefore, a higher radiation exposure is possible. In 35 patients we found radionuclide emigration in 17 cases by whole body scintigraphy, resulting in a 50%-percentile with 68.27%-confidence interval of 1.8 (0.45-4.78)% of the injected yttrium-90-activity. Comparison of 3 groups with the above mentioned therapy modalities resulted in no statistical difference (p>0.05). Because of the found radionuclide emigration, a radiation dose of 0. 1 (0.05-0,18) mSv in women and 0.2 (0.1-0.38) mSv in men was calculated. For lymph nodes, liver, spleen and whole body radiation doses of 619 (154-1644) mSv, 62 (15-165) mSv, 62 (15-165) mSv and 37 (9-99) mSv were calculated. Gonadal radiation dose can be neglected and the morbidity rate for tumors because of the whole body radiation dose is low with a value of 0.4 per thousand. Therefore, radiation synovectomy can be used unlimited by patients age and independent of the therapeutic modality.

The value of renal scintigraphy during controlled diuresis in children with hydronephrosis

Dynamic renal scintigraphy (DRS) during controlled diuresis is the method of choice to diagnose the functional relevance of urinary tract obstruction in children with sonographically demonstrated hydronephrosis. However, there are no commonly accepted scintigraphic criteria for surgical intervention. On the basis of our findings, we propose four stages of washout (WO) of tracer following diuresis: in stage I, WO>50%, neither further diagnosis nor intervention is necessary; in stage II, 50%>/=WO>/=12%, repetition of DRS is advised within 3-4 months; and in stage III, 12%>WO>/=5%, DRS should be repeated within 1-2 months. Only in stage IV, WO<5%, should surgery be done immediately. This procedure reduces surgical interventions by 50% without increasing the risk of residual renal damage.

Imaging of dopamine receptors with [123I]iodobenzamide single-photon emission-computed tomography in neuroleptic malignant syndrome

With the tracer [123I]iodobenzamide ([123I]-IBZM), it is possible to image dopamine receptor occupancy with single-photon emission-computed tomography (SPECT). We report follow-up examinations with IBZM-SPECT in neuroleptic malignant syndrome (NMS) to display D2-receptor availability in the acute phase and during the course of remission. A 27-year-old man was admitted with severe akinesia, rigor, tachycardia, fever, and elevated creatine phosphokinase level (CK) after neuroleptic medication. NMS was diagnosed, and treatment was started with dantrolene, amantadine, and dopamine agonists. IBZM-SPECT examination was performed on days 6, 34, 90, 107, 131, and 201. In the acute state of NMS, there was no binding of IBZM to D2-receptors. SPECT reached almost normal values on day 131, but clinical examination still showed a mild parkinsonian syndrome. With SPECT, the D2-receptor occupancy in NMS could be successfully shown in correlation with extrapyramidal signs. IBZM-SPECT may therefore serve to monitor D2-receptor occupancy in patients at risk for NMS.

The role of magnetic resonance imaging and scintigraphy in the diagnosis of pathologic changes of the mandible after radiation therapy

A prospective study of 85 patients with oral cancer, treated with high-dose radiation therapy, was performed to assess the value of magnetic resonance imaging (MRI) and scintigraphy for diagnosis of pathologic changes in the mandible. During postradiotherapeutic monitoring, radiation osteomyelitis occurred in 12 cases, tumor recurrences infiltrating the mandible in five cases, and progressive periodontal disease in nine cases. MRI permitted early diagnosis of radiation osteomyelitis in 11 out of 12 cases; only two cases were false positive. In scintigraphy with 99mTc-HDP, all alterations of the mandible, such as osteoradionecrosis, tumor infiltration, and periodontitis, showed a high uptake, resulting in a sensitivity of up to 100%, but a low specificity of 57%. Scintigraphy permitted assessment of the extension and location of the lesions. Both methods were superior to conventional radiography and clinical examination and should be integrated into a comprehensive follow-up program after radiation therapy.

Chromosome banding in amphibia. XX. DNA replication patterns in Gastrotheca riobambae (Anura, Hylidae)

Replication banding patterns were induced in the chromosomes of Gastrotheca riobambae by treating cell cultures with 5-bromodeoxyuridine (BrdU) and deoxythymidine (dT). In particular, the time sequence of replication of the highly differentiated XY/XX sex chromosomes was meticulously analyzed throughout the S phase. In the homogametic female, BrdU/dT labeling revealed no evidence of asynchronous replication between euchromatic regions in the XX pair. Minor replication asynchronies between the two X chromosomes were restricted to the heterochromatic C-bands. These results are further proof that dosage compensation in Amphibia for X- or Z-linked genes does not occur by inactivation of one of the two (XX or ZZ) sex chromosomes in the cells of homogametic individuals. In the very large and almost completely heterochromatic Y chromosome of G. riobambae, the various C-bands comprise at least three different structural categories, resulting in a complex pattern of early- and late-replicating bands along the Y chromosome.

[Urinalysis drug control program--a concept for managing drug dependent offenders--report of experience]

The authors report on the results of a care concept for drug-addicted persons. The mechanisms of cooperation between the law enforcement executives, the drug information centres, and the Public Health administration are explained.

[Effects of projection errors on the pantographic diagnosis of TMJ dysfunction]

Extraoral recording methods are bound to produce geometric projection errors. Mirror projections of the curvatures on both sides are a particular problem in clicking joints, thus complicating diagnosis. With the aid of magnetic resonance tomography it has been demonstrated in clinical examples that misinterpretations of the recordings can be avoided by means of computer-supported measuring systems providing accurate projection error correction. Furthermore, it is important that diagnosis be based not only on the usual sagittal plane recordings but also on additional information from the horizontal and frontal planes. Magnetic resonance tomography is then used to confirm the eccentric disc luxation established with the aid of the electronic recordings.

[Etiology of eccentric-posterior and centric-anterior displacements of the articular disc]

40 patients with suspected intraarticular soft tissue displacement have been examined clinically and with the aid of electronic recording methods. The disc position has been verified by means of magnetic resonance tomography. Based on these results and on functional as well as anatomic considerations the development of various forms of articular disc displacement is discussed. Within the pathogenetic considerations particular attention must be paid to the role of dysfunctional excessive mouth opening and the loosening of the posterior cranial attachment of the disc on the base of the skull. This attachment is subjected to individual variations. An intact posterior cranial attachment of the articular disc via the superior stratum of the bilaminar zone at the base of the skull may result in an eccentric posterior displacement under existing dysfunctional loads. On the other hand, lack of repositioning forces due to a weak or loosening attachment may favor the development of centric anterior types of displacement.

Drug interactions I: detection of inorganic nitrite in organic nitrate esters under acidic conditions simulating the human stomach

Both unformulated (bulk) and formulated (drugs) organic nitrate esters (isosorbide dinitrate, nitroglycerin, and pentaerythritol tetranitrate) were studied in the presence and absence of hydrochloric acid to determine if they could be sources of nitrite (and therefore lead to nitrosamine formation) under acidic conditions similar to those found in the stomach. The presence and generation of nitrite ion was detected by a modification of the Griess reaction. Bulk isosorbide dinitrate and nitroglycerin were found to be contaminated with 13.8-121.4 mumoles of inorganic nitrite per mole of nitrate ester. In addition, in the presence of hydrochloric acid, these preparations generated 0.52-1.18 mumoles of inorganic nitrite/mole of nitrate ester/min. Unformulated nitroglycerin generated nitrite at a rate roughly twice that of isosorbide dinitrate. In contrast, no evidence for nitrite contamination or generation by pentaerythritol tetranitrate was found. Tablets and capsules of isosorbide dinitrate contained approximately 27-216 mumoles of nitrite/mole of nitrate ester and, in the presence of hydrochloric acid, generated an average of 0.55 mumole nitrite/min. For isosorbide dinitrate, this rate was similar for bulk and formulated drug. In comparison to isosorbide dinitrate, the amount of nitrite initially present in tablets and capsules of nitroglycerin varied more widely (approximately 25-2290 mumoles nitrite/mole of nitrate ester), and in this case nitrite was generated at higher rates than unformulated drug averaging approximately 4.7 mumoles nitrite/mole of nitrate ester/min. Contrary to a literature report, we found that nitrate ion is not reduced to nitrite by hydrochloric acid (pH 1-3).(ABSTRACT TRUNCATED AT 250 WORDS)