Search

SummaryThe actual number of resin microspheres is approximately 30-60 times higher than glass microspheres per 3 GBq vial. Thus, radioembolization (RE) with resin microspheres exerts an embolization effect besides the radiation effect. This embolization effect can occasionally cause early back flow of the microspheres before application of the entire calculated dose. To avoid these adverse side effects, RE has to be terminated at an earlier time point. Measurement of the residual activity in the delivery box, which includes the v-vial, tube and catheter, to calculate the achieved target dose is often challenging. The aim of the current study was to establish a post-RE measurement method comparable to the glass microspheres method without unnecessary radiation exposure to the staff and risk of contamination. Methods: Two different measurements were performed. First, total radioactivity in the shipping vial was measured in an ion chamber and then it was put in the delivery box and the radiation was measured from a 30 cm distance from the centre of the box with a dosimeter. The required radioactivity was then transferred to the v-vial, and the shipping vial was measured again. After that, the v-vial was measured from the same distance from the centre of the box with dosimeter. Results: Altogether 62 times the shipping vial with different activities were measured with a significant positive correlation between the amount of the activity measured in the iron chamber and the radiation dose, measured with dosimeter (r2 = 0.98; p < 0.001). There was also a strong positive correlation between these measurements of the v-vial (r2 = 0.98; p < 0.001). Conclusion: With measurement of the residual activity in the delivery box using a dosimeter the percentage of the whole injected activity can be easily calculated. This facilitates the calculation of the actual, achieved target and non-target dose in those cases, where therapy had to be stopped because of eminent flow reversal or obstruction.

Summary[177Lu-DOTA0, Tyr3]-octreotate (177Lu-octreotate) in peptide receptor radionuclide therapy (PRRT) offers direct intra-therapeutic dosimetry. The aim of this study was to compare tumour and non-tumour parameters and assess intra-individual variations. Patients, methods: Retrospective analysis of 53 consecutive PRRT treatment cycles (mean activity of 7.53 ± 0.46 GBq 177Lu-octreotate, intended four cycles at intervals of 10–14 weeks, standard nephroprotection) in 27 GEP NET patients. Extended planar dosimetry with serial wholebody imaging on selected, non-superimposed tumour and non-tumour regions; liver (LM), bone (BM), and other (OM) metastases. The per-cycle variation was compared with posttreatment response (CT/MRI three months post-treatment, modified SWOG criteria). Results: Residence time in tumor lesions (133–147 h) exceeded that in kidneys (93 h). Tumour-to-kidney absorbed dose ratios ranged from 14 to 28 (LM, BM, OM). Intra-individual per-cycle dose variation was insignificant for kidneys, but significant for metastases (LM, BM, and OM; p < 0.05). The mean per-cycle decrease of tumour absorbed dose (_D/A0[%]) was linked to morphologic response after PRRT. A mean decrease of >20% was predictive of a partial or minor remission in all 11 evaluable patients, while absent significant dose reduction indicated stable or progressive disease in 4/5 patients. The dose decrease was unrelated to volume effects and also observed for BM. Conclusion: Besides confirmation of a favourable tumour-to-kidney parameter relation for 177Lu-octreotate, stepwise intra-lesional comparison seems to imply a prognostic impact of tumor dosimetry: The early per-cycle change _D/A0 between treatment cycles may predict the outcome after PRRT. Larger studies are needed to confirm this finding.

Amphetamine is stored by brain tissue and permits its scintigraphic imaging, particularly with the single-photon emission computed tomography (SPECT). A total of 60 scintigraphic investigations in 54 patients were done. Investigations were done using an emission computed tomograph (rotating gamma-camera) after application of 123I-N-isopropyl-amphetamine. In 6 out of 24 patients with epilepsy a focus in agreement with EEG findings could be established despite negative cranial computed tomography (CT). In 4 out of 25 patients with cerebrovascular disease diminished perfusion was demonstrated although cranial CT was normal. In 10 out of 20 cases the extent of functional lesions demonstrated by SPECT was larger than could be assumed by cranial CT findings. Three patients with migraine and negative CT findings showed disorders of perfusion in the amphetamine-SPECT which were in agreement with the EEG. Brain SPECT using 123I-labelled amphetamines thus offers the possibility to demonstrate functional perfusion and metabolic disorders which show no morphologic correlate in the cranial CT. In addition, foci demonstrated in cranial CT can be more precisely defined in their functional extent using the SPECT.

Eleven patients with Alzheimer type dementia were investigated by single-photon-emission computed tomography (SPECT) using 99mTc-hexamethylpropylene-aminoxim (HM-PAO). Nine had a typical, symmetrically reduced enrichment in the parieto-temporo-occipital area. In three of these nine patients a similar pattern was recorded additionally in the frontal, in the remaining two in the temporal or parietal region. In a semi-quantitative evaluation radioactivity concentrations in the cerebrum and cerebellum were compared. It demonstrated that there was in relation to the cerebellum a reduced concentration in seven of the eight studied cerebral regions. The relative blood flow of the parieto-temporo-occipital region was most markedly affected and in patients with Alzheimer type dementia was reduced by 25% below that of normal subjects. The results indicate that cerebral SPECT with HM-PAO is a reasonable method of investigation to confirm the diagnosis of "Alzheimer type dementia" and exclude other cerebral disease, especially if pathognomonic findings are to be obtained.

SummaryAim: Dosimetry in 131I-lipiodol therapy for hepatocellular carcinoma (HCC) in the hitherto largest existing patient cohort. Patients, methods: 38 courses of intra-arterial 131I-lipiodol therapy with a total activity up to 6.7 GBq were performed in 18 patients with HCC. Liver and tumour volume were measured by computed tomography (CT) and 131I activity by scintigraphy on day 3, 6, 14, 28 and 42 after injection. Lipiodol deposition in tumour nodules as shown by CT rendered definite attachment to scintigraphic data possible. The radiation dose in tumour nodules, liver and lungs was calculated according to the MIRD concept and the tumour dose related to pre-therapeutic tumour volume, response and survival. Results: Mean tumour dose was 23.6 ± 3.6 Gy (14.2 ± 2.1 mGy/MBq) with maximal 162 Gy (90.1 mGy/MBq) after one and 274 Gy after three courses. The dose to nontumourous liver was 1.9 ± 0.2 Gy (1.2 ± 0.1 mGy/MBq) and the mean dose ratio of tumour / nontumourous liver 11.1 ± 1.7 (max. 82). The pulmonary dose was 25.9 ± 1.8 mGy (16.3 ± 1.2 μGy/MBq) and therefore much lower. There was a reciprocal relation between tumour dose and pretherapeutic tumour volume. Tumour dose had no effect on response or survival. Conclusion: High radiation doses are particularly in small tumour nodes achievable but not necessarily related to tumour response. The dose of non-tumourous liver and lungs is much lower.

SummaryAim: To evaluate the efficacy and tolerance of iodine- 131-lipiodol (131I-lipiodol) for hepatocellular carcinoma (HCC) in German long term patients and comparison with medically treated controls. Patients, Methods: 38 courses of intra-arterial 131I-lipiodol therapy with a total activity up to 6.7 GBq were performed in 18 patients with HCC (6 with portal vein thrombosis). Liver and tumour volume and lipiodol deposition were measured by computed tomography and 131I activity by scintigraphy. Therapeutic efficacy was determined by tumour volume change and matched-pairs analysis in comparison to medically (i.e. tamoxifen or medical support) treated patients. Results: Tumour volume decreased in 20/32 index nodules (63%) after the first course. Repeated therapy frequently resulted in further tumour reduction. Overall response to treatment was partial in 11 nodules, minor response in 4 nodules, and disease was stable in 12 and progressive in 5. Significant response was associated with pretherapeutic nodule volume up to 150 ml (diameter of 6.6 cm). Survival rate after 3, 6, 9, 12, 24 and 36 months was 78, 61, 50, 39, 17, and 6%. Matched-pairs analysis of survival revealed 131I-lipiodol to be superior to medical treatment. The most important side effect was a pancreatitis-like syndrome whereas overall tolerance was good. Conclusion: The long term results confirm that HCC therapy with 131I-lipiodol is effective and probably superior to medical treatment. Tumour nodules of up to 6 cm diameter are well suited for this therapy even in the presence of portal vein thrombosis.

Zusammenfassung Ziel: Die effiziente, medikamentöse Behandlung von Patienten mit schmerzhaften, disseminierten Knochemmetastasen stellt ein therapeutisches Problem dar. Die systemische Radionuklidtherapie kommt als Alternative in Frage. In der vorliegenden Studie wurde die Effektivität von Rhenium-186 HEDP zur Schmerztherapie bei disseminierten Knochenmetastasen evaluiert. Methoden: 30 Patienten, die wegen schmerzhafter Knochenmetastasen analgetisch behandelt wurden, erhielten -teilweise mehrfach- Injektionen von jeweils 1295 MBq 186Re HEDP zur Schmerzbehandlung. Ergebnisse: Bei 70% der Patienten ließ sich eine Schmerzreduktion erreichen. Die Dauer des Ansprechens auf die Therapie betrug im Mittel 4 Wochen (1 Wo-2,5 Mon). Die wesentlichen Nebenwirkungen bestanden in einem geringen Abfall der Thrombozyten (durchschnittl. 30000/ul) und einer kurzzeitigen Verstärkung der Schmerzsymptomatik (Flare-Effekt). Schlußfolgerung: Bei Patienten mit schmerzhaften, disseminierten Knochenmetastasen kann die Schmerztherapie mit Rhenium-186 HEDP komplementär zur medikamentösen Therapie eingesetzt werden.

ZusammenfassungDie striatale Dopamin-D2-Rezeptoranreicherung von 123J-IBZM wurde bei 32 Patienten (18 ohne und 14 mit neuroleptischer Therapie) semiquantitativ unter Anwendung verschiedener ROI-Techniken ausgewertet. Ziel der Studie war es, die von verschiedenen Untersuchern gefundenen unterschiedlichen Quotienten (Striatum/Kortex) unter dem Aspekt der angewandten ROI-Technik zu untersuchen. Es konnte gezeigt werden, daß bei Verwendung des gleichen SPECT-Systems keine größeren Unterschiede zwischen Rechteck-ROI und manuell erstellten ROI gleicher Größe auftreten. Eine hochsignifikante Trennung zwischen behandelten und unbehandelten Patienten ergab sich für alle untersuchten Auswerteverfahren. Der ermittelte Quotient wird wesentlich durch das Auflösungsvermögen der Kamera und nur relativ geringfügig durch die verwendete ROI-Technik bestimmt. Die Quotienten verschiedener Arbeitsgruppen sind quantitativ nicht miteinander vergleichbar.

Summary Purpose: This investigation was performed to compare the hemodynamic results of the transjugular intrahepatic portosystemic shunt, a new interventional treatment for portal hypertension, with those observed after the established surgical shunt interventions. Methods: We examined 22 patients with portal hypertension due to liver cirrhosis before and after elective TIPS by liver perfusion scintigraphy. The relative portal perfusion was determined before and after the shunt procedure. Additionally, we measured the portal pressure gradient (PPG: portal-central venous pressure, mmHg). Results: Prior to TIPS, the relative portal perfusion was significantly reduced to 22 ± 9.1%. After the intervention we calculated values of 23.1 ± 10,7% in the TIPS-group (p = 0.67; not significant). In spite of unchanged portal perfusion, the portal pressure was significantly (p

ZusammenfassungBei 31 Patienten mit Apoplexie (n = 30) bzw. PRIND (n = 1) wurde eine Hirn-SPECT mit 123J-markierten Amphetaminen durchgeführt. Hierbei fand sich bei 14 (= 45%) Patienten eine gekreuzte zerebellare Diaschisis. In allen Fällen lag eine zwischen 1 Woche und 7 Jahren bestehende Hemiplegie vor. Demgegenüber bestand bei den Patienten ohne gekreuzte zerebellare Diaschisis mit einer Ausnahme keine Hemiplegie. Das Phänomen einer solchen Diaschisis ist am ehesten darauf zurückzuführen, daß bei Hirninfarkt bzw. -blutung die kontralaterale Körperhälfte gelähmt ist und damit die entsprechende Kleinhirnhemisphäre weniger periphere Reize über spino-zerebellare Bahnen erhält.

Derivatives of propylene-amine-oxime (PnAO) have been synthesized which form a neutral lipid-soluble complex with 99mTc and can be supplied as freezedried kits. The complexes cross the intact blood-brain barrier. This report shows the brain uptake, early kinetics and biodistribution in normal adult baboons of 5 99m Tc-PnAO derivatives and 2 isomers of one of the tested derivatives (HM-PAO). The brain uptake of the favoured dl-isomer of HM-PAO reaches its maximum of 4.3% (whole brain/whole body) 1 min p. i. and a clearance of less than 8% was observed 23 min p. i.

Bei neun Patienten mit Verdacht auf psychogene Anfalle und drei Patienten mit bekannter Epilepsie wurde vor und wahrend eines zerebralen Anfalls eine HMPAO-SPECT durchgefuhrt. Bei den Patienten, bei denen sich der Verdacht auf psychogene Anfalle bestatigte, wurden keine - oder nur diskrete - Anderungen der regionalen Durchblutung gefunden. Bei den Patienten mit Epilepsie zeigten sich interiktal zum Teil unauffallige Befunde, iktal waren bei allen Patienten deutliche umschriebene Mehrdurchblutungen nachzuweisen. Die HMPAO-SPECT ist zwar in der raumlichen Auflosung der PET unterlegen, bietet in der Epilepsiediagnostik aber den Vorteil, das das Radio-pharmakon wahrend eines Anfalls injiziert und die SPECT zu einem spateren Zeitpunkt durchgefuhrt werden kann.

New developments in radiopharmacology of 123l-labeled metabolic tracers and single-photon emission computerized tomography (SPECT) allow now-a-days the assessment of parameters of cardiac energy metabolism in well-defined areas of the heart muscle. This article will present a brief outline of the basic pathophysiological principles used in the application of 123l-labeled phenyl fatty acids for the evaluation of CAD. First clinical results suggest an important application of cardiac fatty acid metabolic imaging to the detection, localisation and conceivable quantitation of myocardial ischemia, myocardial infarction and assessment of tissue viability. In addition to the diagnostic applications in CAD, cardiac fatty acid metabolic imaging may provide new perspectives to pathophysiological investigations of the coupling of local flow and substrate utilisation in vivo and the effect of therapeutic interventions.

Extensive diagnostic measures are necessary to clarify the indication for surgery in patients suffering from epilepsy that is refractory to treatment. Within the overall framework of neuropsychological diagnosis we conducted the Wada test, injecting 200 mg (or 3 mg/kg body weight) of sodium amytal on different days, in each case into the left or right internal carotid artery. This results in a 3-5 minute anaesthesia of the relevant hemisphere. By means of a neuropsychological short test it is possible to determine the performance of the non-blocked hemisphere. The extent of the blocking is also determined by simultaneous i.v. injection of HM-PAO (hexamethyl propylene amine oxime) labelled with 99m Tc, the uptake of which by various cerebral regions is visualised via SPECT. The Wada test supplies information on the lateralisation of cognitive functions (speech, memory etc.) whereas the SPECT examination enables additional determinations not only of processes that must be characterised as diaschisis, but also on the extent of blocking of a hemisphere. The results supply clues to expected postoperative cognitive deficits and thus enable a differentiated assessment of the indication for surgery. This is discussed on the basis of two clinical cases.