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Objectives: Today, acute cardiac rejection is detected by endomyocardial biopsy, which harbours many risks. Thus, there is a necessity for less invasive methods. Since interleukin-2 (IL2) is over-expressed in acute graft rejection, we use radioactive DNA-fragments complementary to the mRNA of IL2 to detect graft rejection scintigraphically. Methods: In a rat model of acute graft rejection, the oligonucleotide sequence complementary to the mRNA of IL2 is labelled with 99m-Technetium and injected intravenously. Scintigraphic and Geiger-counter activity of the transplants are evaluated and correlated with the current rejection classification of the International Society for Heart and Lung Transplantation (ISHLT). Results: From the fourth postoperative day onwards, the scintigraphic images show a significant increase of radioactivity (p < 0.05) in the rejectedorgans thanin theacceptedgrafts. Whilescintigraphyis not significantlycorrelated with thestandardrejectionsclassification ofthe ISHLT,thereissignificantcorrelationbetweentheISHLTclassificationandradioactivityintheGeiger-counteranalysis.Conclusions:Radioactively labelled anti-sense-oligonucleotides against mRNA of IL2 may be a promising approach for the detection of acute transplant rejection in vivo. # 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

The reaction of pyridine with ditechnetium decacarbonyl [Tc2(CO)10] (1) leads to a novel ortho-pyridyl-ditechnetium hydrido complex, [Tc2(mu-H)(mu-NC5H4)(NC5H5)2(CO)6] (2) and its precursor [Tc2(mu-CO)2(NC5H5)2(CO)6] (3). At ambient temperature 1 was found to react slowly with pyridine to afford the substitution product 3 after 120 h. However, heating the reaction mixture to reflux exclusively leads to the pyridine-ortho-metalated complex 2 in only 30 min. Similarly, complex 3 can be converted completely into 2 upon heating in pyridine for 30 min. Both compounds 2 and 3 were characterized by NMR spectroscopy and X-ray analysis. Both compounds 2 and 3 show a complex dynamic behavior in solution that was investigated by one-dimensional and two-dimensional NMR spectroscopy. Both compounds 2 and 3 show isomerization in solution according to the relative position of the non-bridging pyridine ligands. For 2 the existence of three isomers was shown at equilibrium conditions, 2a (56%) with trans-diaxial, 2b (38%) with cis-diaxial, and 2c (6%) with axial-equatorial arrangement of the non-bridging pyridines. For 3 an equilibrium was detected between two isomers, 3a (67%) with a cis-diaxial and 3b (33%) with a trans-diaxial arrangement of the pyridines.

Our aim was to use PET/MRI to evaluate and compare the uptake of 18F-FDG, 3-deoxy-3-18F-fluorothymidine (18F-FLT), and 18F-fluorethylcholine (18F-FEC) in human pancreatic tumor cell lines after xenotransplantation into SCID mice and to correlate tumor uptake with gene expression of membrane transporters and rate-limiting enzymes for tracer uptake and tracer retention. Methods: Four weeks after orthotopic inoculation of human pancreatic carcinoma cells (PancTuI, Colo357, and BxPC3) into SCID mice, combined imaging was performed with a small-animal PET scanner and a 3-T MRI scanner using a dedicated mouse coil. Tumor-to-liver uptake ratios (TLRs) of the tracers were compared with gene expression profiles of the tumor cell lines and both normal pancreatic tissue and pancreatic tumor tissue based on gene microarray analysis and quantitative polymerase chain reaction. Results:18F-FLT showed the highest tumor uptake, with a mean TLR of 2.3, allowing correct visualization of all 12 pancreatic tumors. 18F-FDG detected only 4 of 8 tumors and had low uptake in tumors, with a mean TLR of 1.1 in visible tumors. 18F-FEC did not show any tumor uptake. Gene array analysis revealed that both hexokinase 1 as the rate-limiting enzyme for 18F-FDG trapping and pancreas-specific glucose transporter 2 were significantly downregulated whereas thymidine kinase 1, responsible for 18F-FLT trapping, was significantly upregulated in the tumor cell lines, compared with normal pancreatic duct cells and pancreatic tumor tissue. Relevant genes involved in the uptake of 18F-FEC were predominantly unaffected or downregulated in the tumor cell lines. Conclusion: In comparison to 18F-FDG and 18F-FEC, 18F-FLT was the PET tracer with the highest and most consistent uptake in various human pancreatic tumor cell lines in SCID mice. The imaging results could be explained by gene expression patterns of membrane transporters and enzymes for tracer uptake and retention as measured by gene array analysis and quantitative polymerase chain reaction in the respective cell lines. Thus, standard molecular techniques provided the basis to help explain model-specific tracer uptake patterns in xenotransplanted human tumor cell lines in mice as observed by PET.

SummaryAim: Radiosynoviorthesis using intraarticular injection of beta-emitting radiocolloids is increasingly performed throughout Europe in patients with inflammatory joint disease. It is a cost-effective and safe treatment, local complications are very rare with only eight cases mentioned in the literature so far. No recommendations for therapy of tissue necrosis, infection or thromboembolism after radiosynoviorthesis are available. Methods: Using a standardized questionary, 260 nuclear medicine physicians and 20 medical liability insurances were asked for the kind and frequency of complications after radiosynoviorthesis between 1998 and 2003. The survey was terminated after nine months with a response of only 25.7%. Results: A total of 53 severe complications were documented (28 necroses, 12 thromboses, 13 joint infections). Eight other complications were seen but difficult to correlate directly with radiosynoviorthesis. Tissue necroses from yttrium-90 were successfully treated by surgical excision and closure of the defect. Rhenium-186-induced ulcers healed by hyperbaric oxygen therapy in two cases. Lesions from erbium-169 showed restoration by conservative treatment. Thromboembolic events happened after radiosynoviorthesis in joints of the lower limb only, mostly treated by conventional anticoagulation. Intraarticular infections showed restoration after intraarticular antibiotics in the majority of cases. Conclusion: Severe complications after radiosynoviorthesis seem to be rare. However, because of the low return rate, a reliable frequency cannot be calculated. Nevertheless, important advices regarding treatment concepts can be taken from our data.

Summary Aim of this study was to prove the clinical value of nuclear medicine procedures to detect the sentinel lymph node (SLN) for SLN biopsy. Methods: In 132 patients with breast cancer we performed lymph scintigraphy of the breast as well as both pre- and intraoperative gamma probe measurements correlating the results with the findings of histopathology. Results: SLN were detectable in 62 of 110 patients according to a sensitivity of 56% when scanning was performed only at 1-2 h p.i. while the sensitivity increased to 86% (19 of 22 pts.) if sequential images were acquired up to 2 h p.i. One or more SLN were identified by a handheld gamma probe transcutaneously prior to surgery in 96% (113 of 118 pts.) of the patients who showed up with no clinically suspected lymph node metastases. Intraoperatively, in additionally 2 patients the SLN could be found resulting in a sensitivity of 97% (115 of 118 pts.). In only 3 patients with clinically no tumor spread to axillary lymph nodes no SLN could be identified by the probe. Skip lesions, i.e. lymph node metastases in patients with tumorfree SLN, occured in 2 cases: due to SLN biopsy in these patients lymph node staging was false negative compared to conventional staging by means of axillary lymph node dissection. Conclusion: The results demonstrate a high preoperative detection rate of SLN in patients with breast cancer using lymph scintigraphy and gamma probe measurements. Thus, nuclear medicine is capable of providing the basic requirements for SLN biopsy in the daily routine.

Summary Aim of this study was to validate a recently introduced new and easy-to-perform method for quantifying bone uptake of Tc-99m-labelled diphosphonate in a routine clinical setting and to establish a normal data base for bone uptake depending on age and gender. Methods: In 49 women (14-79 years) and 47 men (6-89 years) with normal bone scans as well as in 49 women (33-81 years) and 37 men (27-88 years) with metastatic bone disease whole-body bone scans were acquired at 3 min and 3-4 hours p.i. to calculate bone uptake after correction for both urinary excretion and soft tissue retention. Results: Bone uptake values of various age-related subgroups showed no significant differences between men and women (p >0.05 ). Furthermore, no differences could be proven between age-matched subgroups of normals and patients with less than 10 metastatic bone lesions, while patients with wide-spread bone metastases revealed significantly increased uptake values. In both men and women highest bone uptake was obtained (p

Summary Aim of this study was to assess the radiation exposure for the personnel in the operating room and in the pathology laboratories caused by radioguided SLN localization in breast cancer. Methods: In 15 patients dose rates were measured at various distances from the breast and tumor specimens during operation and pathological work-up at 3-5 h after peritumoral injection of 30 MBq Tc-99m-nanocolloid. Results: The dose rates were 84.1 ± 46.4 μGy/h at 2.5 cm, 3.57 ± 2.14 μGy/h at 30 cm, 0.87 ± 0.51 μGy/h at 100 cm, and 0.40 ± 0.20 μGy/h at 150 cm in the operating room and 44.4 ± 27.8 μGy/h at 2.5 cm, and 1.66 ± 1.34 μGy/h at 30 cm in the pathology laboratories. From these data the radiation exposure was calculated for 250 operations per year assuming a mean exposure time of 30 min for the surgical team members and of 10 min for the pathology staff. Under these conditions the finger dose is 10.5 mGy for the surgeon, and 5.55 mGy for the pathologist. The wholebody doses are 0.45 mSv, 0.11 mSv, 0.05 mSv, and 0.21 mSv for the surgeon, the operating room nurse, the anesthetist, and the pathologist, respectively. Conclusion: Since the radiation risk to staff members is low, a classification of the personnel in the operating room and in the pathology laboratories as occupational radiation exposed workers is not necessary.

PURPOSE Salivary gland impairment is a well-recognized side effect following high-dose radioiodine treatment (HD-RIT). Since differentiated thyroid cancer has a good prognosis, reduction of long-term side effects is important. Therefore, the effect of amifostine was studied in HD-RIT. PATIENTS AND METHODS Parenchymal function was assessed by quantitative salivary gland scintigraphy performed prospectively in 50 patients with differentiated thyroid cancer before and 3 months after HD-RIT with either 3 GBq iodine ((131)I) (n=21) or 6 GBq (131)I (n=29) in a double-blind, placebo-controlled study. Twenty-five patients were treated with 500 mg/m2 amifostine intravenously before HD-RIT and 25 patients served as controls, who received physiologic saline solution. Xerostomia was graded according to World Health Organization (WHO) criteria. RESULTS Before HD-RIT in 25 control patients, uptake of technetium-99m (99mTc)-pertechnetate was 0.45%+/-0.16% and 0.42%+/-0.16% in parotid and submandibular glands, respectively. Three months after HD-RIT, parenchymal function was significantly (P < .001) reduced by 40.2%+/-14.1% and 39.9%+/-15.3% in parotid and submandibular glands, respectively. Nine control patients developed grade I and two grade II xerostomia. In 25 amifostine-treated patients, uptake of 99mTc-pertechnetate was 0.46%+/-0.16% and 0.43%+/-0.17% in parotid and submandibular glands, respectively. Three months after HD-RIT, parenchymal function of salivary glands was not significantly altered (P=.691) and xerostomia did not occur in any of these patients. CONCLUSION Parenchymal damage in salivary glands caused by HD-RIT can significantly be reduced by amifostine, which may improve the quality of life of patients with differentiated thyroid cancer.

BACKGROUND Lymphoscintigraphy has been used since the early 1960s to demonstrate lymphatic drainage of head and neck tumors, but did not prove satisfactory. With the increasing importance of highly sophisticated neck dissection procedures, lymphoscintigraphy may have greater diagnostic impact. This assumes that lymphoscintigraphy will allow an accurate correlation of lymphatic drainage with anatomic structures. In this paper, we report on a method of lymphoscintigraphy with simultaneous body contouring. METHODS Double-tracer lymphoscintigraphy was performed in 78 patients with squamous cell carcinoma. Patients received 100 MBq 99mTc-colloid in 0.1-0.2 ml in 3-4 peritumoral localizations. Ten patients were injected during surgery. Two milliliters of perchlorate solution were given orally in order to block the thyroid. Twenty minutes later patients received 50 MBq 99mTc-pertechnetate i.v. for body contouring. Planar images were obtained over 5 min each at 30 min and 4-6 h after injection from anterior, right lateral and left lateral using a LFOV-gamma camera. RESULTS The thyroid was not visualized in any of the patients. In 28 of 78 patients (36%), the injection site was the only focal activity seen. In 50 of 78 patients (64%), lymph drainage was observed. Thirty-six of 78 patients (46%) showed unilateral lymphatic drainage, and 14 of 78 (18%) showed bilateral drainage. In all 50 patients showing lymphatic drainage, lymph nodes could be easily assigned to the six cervical lymph node compartments described. CONCLUSIONS Double-tracer lymphoscintigraphy enables an accurate correlation of cervical lymph nodes and anatomic structures of the head and neck region. These findings suggest that the impact of these studies on the preoperative planning for neck dissection should be reevaluated.

Up to now there has been no routinely used and easy-to-perform method for the quantification of bone uptake. Therefore, we have evaluated the clinical practicability of a new and simple method for the measurement of bone uptake based upon conventional three-phase bone scanning. In 13 patients with normal bone scans, whole-body scintigrams were obtained at 3 min and 1, 2, 3, 4, 5, 6 and 24 h after injection of 600 MBq technetium-99m hydroxymethylene diphosphonate (HMDP). Using a conventional region of interest technique, fitted time-activity curves of soft tissue and urinary excretion were established, and bone uptake was calculated from these data as the total whole-body activity minus both soft tissue activity and urinary excretion. Subsequently, the new method was tested in routine patient management: 32 healthy patients and five patients with different types of metabolic bone disease were investigated, measurements being performed only at 3 min and 3–4 h p.i. during conventional three-phase bone scanning. In the multi-imaged patient subset, soft tissue activity decreased exponentially, reaching a plateau after 6 h with a residual activity of about 14% of initial total whole-body activity. Bone uptake reached quite a stable plateau of about 27% as early as 3 h p.i., with no significant changes up to 24 h. Healthy patients of the two-scan group showed no differences in bone uptake (mean uptake values were 24.1% in women and 26.9% in men), whereas in patients with metabolic bone disease bone uptake was significantly higher, with a mean of 48% (P

BACKGROUND Since its introduction in 1965 salivary gland scintigraphy has been an established method to simultaneously investigate excretion function in major salivary glands. In order to elucidate parenchymal function of salivary glands, several authors described various quantitative and semiquantitative methods. However, no standardized protocol for quantitative salivary gland scintigraphy has been established so far. METHODS Therefore, in this paper we report on a standardized and validated acquisition protocol for salivary gland scintigraphy using 99mTc-pertechnetate. RESULTS A normal data base for both parenchymal and excretion function is given in detail. In addition, the diagnostic value of salivary gland scintigraphy is reviewed in various clinical settings, such as mild parenchymal damage in beginning Sjogren's syndrome, proof of functional obstruction in sialolithiasis with and without parenchymal damage, and parenchymal damage following radioiodine treatment. In a second part, applications of salivary gland scintigraphy in current clinical research are described, and radiation protection of salivary glands in rabbits and patients treated with high doses of I-131 are discussed. CONCLUSIONS Salivary gland scintigraphy is a study that is easily performed and well tolerated by the patient. It yields quantitative parameters for parenchymal function and excretion fraction.

The aim of this study was to evaluate 201Tl whole-body imaging in the detection of metastases prior to surgery in patients with malignant melanoma. Whole-body imaging was performed in 30 patients with known or suspected metastases 5 and 30 min after administration of 150 MBq 201Tl. The imaging results were compared with the histopathological findings in each patient on a lesion-by-lesion basis. Of the 39 metastases proven histopathologically, 34 were detected by 201Tl imaging (sensitivity = 87%), including 4 in-transit metastases and one inguinal lymph node metastasis which were unknown prior to investigation. Due to these additional findings on 201Tl imaging, scheduled surgical therapy was changed in three patients. 201Tl imaging was false-negative in four lymph node metastases and one skin lesion, and there were two false-positive 201Tl scans with tracer accumulation in inflammatory sites. The mean target-to-background ratio on the true-positive scans was 1.72 +/- 0.37 and 1.67 +/- 0.41 (P > 0.05) at 5 and 30 min post-injection respectively. In conclusion, 201Tl whole-body imaging appears sensitive and simple to perform in the detection of metastases prior to surgery in melanoma patients.

Zusammenfassung Ziel: Mit einer standardisierten, quantitativen Sialoszintigraphie (qSZ) sollte geprüft werden, ob auch durch relativ niedrige, im Rahmen gutartiger Schilddrüsenerkrankungen applizierte Aktivitäten von Radiojod subtile Speicheldrüsenschäden meßbar sind. Zusätzlich wurde die Prävalenz von Sialopathien bei Schilddrüsenpatienten ermittelt. Methoden: Im Rahmen der Schilddrüsenszintigraphie wurde eine qSZ nach i.v Injektion von 36-126 MBq 99mTc-Pertechnetat durchgeführt. Referenzbereiche für den 99mTc-Uptake und die Exkretionsfraktion nach Stimulation wurden an 312 Speicheldrüsengesunden ermittelt. 144 Patienten wurden vor und 3 Monate nach einer Radiojodtherapie untersucht. Bei weiteren 674 Schilddrüsenpatienten wurden die Ergebnisse der qSZ zur Erfassung der Prävalenz von Speicheldrüsenschäden ausgewertet. Ergebnisse: Im Referenzkollektiv betrug der Uptake 0,45 ± 0,14% bzw. 0,39 ± 0,12% und die Exkretionsfraktion 49,5 ± 10,6% bzw. 39,1 ± 9,2% in den GH. parotides bzw. submandibulares. Trotz intratherapeutischer Gabe von Sialogoga war eine signifikante und mit der Aktivität korrelierende Einschränkung der Parenchymfunktion von 14-90% nach Applikation von 0,4 bis 24 GBq 1-131 meßbar. Die Prävalenz prätherapeutischer Sialopathien betrug an singulären Speicheldrüsen 77/674 = 11,4%, die der globalen Speicheldrüseninsuffizienzen lag bei 52/674 = 7,7%. Schlußfolgerung: Die im Rahmen der Schilddrüsenszintigraphie durchführbare qSZ ist ein einfach durchzuführendes Verfahren ohne zusätzliche Strahlenbelastung. Sie sollte zur Dokumentation der Speicheldrüsenfunktion vor jeder Radiojodtherapie durchgeführt und zum Ausschluß bzw. zur Quantifizierung einer schon bei niedrigen 131I-Aktivitäten nachweisbaren Parenchymschädigung nach

This study was undertaken to quantify salivary gland parenchymal damage after radioiodine treatment with a standard protective regimen of ascorbic acid. Altogether, 106 patients underwent quantitative salivary gland scintigraphy with 99Tcm-pertechnetate prior to and 3 months after radioiodine therapy. Parenchymal function was quantified by calculating 99Tcm-pertechnetate uptake 13 min post-injection. Patients received 131I doses ranging from 400 MBq to 24 GBq (cumulative). Among the patients who received large doses of 131I, severe parenchymal destruction could be visually analysed as well as quantitatively evaluated. In contrast, after low-dose radioiodine treatment, mild parenchymal impairment was demonstrated by quantitative evaluation only. In conclusion, standardized quantitative salivary gland scintigraphy is essential for the reliable detection of mild parenchymal malfunction. Despite the standard protection regimen using ascorbic acid as a sialogogue, radioiodine therapy induces loss of salivary gland parenchymal function even with low doses of 131I.

Hemimandibular elongation is characterized by persistent unilateral growth, resulting in unilateral overgrowth of the mandible. The surgical treatment strategy depends on condylar growth activity, which cannot be assessed by conventional radiological procedures. Therefore, this study was undertaken to evaluate the usefulness of bone scanning in hemimandibular elongation. Twenty-seven patients underwent bone scanning prior to surgery. Growth activity was quantified by calculating the L/R ratio. In the case of more pronounced right-sided growth producing a L/R ratio of less than 1, inverse values were used. Corrective osteotomy was performed in the patients with a L/R1.10, whereas patients with a L/R1.10 underwent condylectomy. Twenty-three patients had a L/R ratio1.10 and were followed up for 3 years. In 16 patients, a corrective osteotomy was performed without any relapse post-operatively. Four patients showed marked unilateral increased uptake. In one patient, a pre-operative bone scan was not considered, and corrective osteotomy was performed with subsequent recurrence of unilateral overgrowth of the mandible. The final patient underwent condylectomy without relapse. In two patients, it was decided to repeat the bone scan after a follow-up period of 12 months. In conclusion, bone scanning has significant clinical value in pre-operative decision-making in hemimandibular elongation by guiding surgical strategy with respect to condylar growth activity.

The aim of this study was to evaluate somatostatin receptor scintigraphy (SRS) in patients with meningioma proven or suspected on magnetic resonance imaging (MRI). Prior to surgery, 47 patients were investigated up to 24 h following the injection of 200 MBq 111 In-octreotide. Tracer uptake was compared with the histological presence of meningioma. Histology revealed 43 meningiomas, 3 neurinomas and 1 ependymoma. A true-positive SRS result was obtained in 36 patients, in 13 of whom a tumour volume of < 10 ml was noted. A false-negative SRS result was obtained in seven patients, all of whom had a tumour volume of < 10 ml. Whereas MRI alone was decisive in 38 of 47 patients, it could only provide a differential diagnosis in the remaining 9 patients. A positive SRS result confirmed meningioma in five of these patients, and a negative SRS result excluded meningioma in the other four. Therefore, cases of SRS-negative meningioma do exist. Nevertheless, significant clinical benefit can be obtained from functional imaging with 111 In-octreotide in patients with an inconclusive MRI result, as large meningiomas can be excluded by scintigraphy alone, whereas meningiomas of any size may be confirmed in combination with specific MRI results.

The aim of this study was to evaluate somatostatin receptor scintigraphy (SRS) in the staging of patients with small cell lung cancer. Prior to chemotherapy, 20 patients were investigated up to 24 h following an injection of 200 MBq 111In-octreotide. Following chemotherapy and restaging, four patients were re-evaluated. Primary tumour was detected in 18 of 23 studies, which exhibited increasing target-to-back-ground ratios over time. Lymph node metastases and distant metastases were detected in 7 of 27 and 8 of 31 sites, respectively. Thus, the overall sensitivity for detecting metastases was less than 26%. SRS did not result in any upstaging of patients. We conclude that in patients with small cell lung cancer, functional imaging by SRS has no impact on clinical decision making.

The aim of this study was to examine patients with long-standing Graves' ophthalmopathy using 111In-octreotide scintigraphy. Sixteen patients with inactive ophthalmopathy of up to 114 months duration and 14 normals were investigated for 48 h following an injection of 200 MBq 111In-octreotide. No significant tracer accumulation in the orbital region could be identified in any of the patients with long-standing Graves' ophthalmopathy. The orbit to brain (O/B) ratios after 24 and 48 h were 2.39 +/- 0.36 and 2.15 +/- 0.44 versus 2.17 +/- 0.33 and 2.20 +/- 0.37 for the patients and normals, respectively (N.S.). 111In-octreotide accumulation in ophthalmopathy described in the literature may thus be a passing event limited to its active stage, which is consistent with the concept of imaging a lymphocytic infiltration. In this study, the lack of accumulation of 111In-octreotide in the orbital region during the inactive stage demonstrates an absence of somatostatin receptors in orbital tissue itself. Thus, in patients with inactive Graves' ophthalmopathy, there is no basis for a diagnostic approach with somatostatin.

ZusammenfassungEs wird ein einfaches und kostengünstiges Lösungskonzept zur kompletten digitalen Verwaltung einer nuklearmedizinischen Klinik vorgestellt. Die Ausgangssituation war durch fünf unterschiedliche Gammakamerafabrikate vorgegeben, wovon eines bereits mit einem auf Macintosh-PC-Basis arbeitenden Rechner, ICON, ausgestattet war. Die verbleibenden vier Geräte wurden ebenfalls an ICON-PCs adaptiert und in ein Macintosh-LAN, bestehend aus weiteren 15 PCs, integriert, so daß die gesamte Bildakquisition, -Verarbeitung, Befundung, Dokumentation und Archivierung über eine einheitliche, benutzerfreundliche Oberfläche komplikationslos möglich ist. Die Patientendatenverwaltung erfolgt auf demselben LAN über ein kommerziell erhältliches Datenbanksystem, an das ein selbstentwickeltes Bild- und Dokumenten-Archiv angebunden worden ist. Das System erlaubt ein völlig aktenfreies Patienten-, Daten- und Bildmanagement zu vergleichsweise moderaten Kosten von etwa 11 × 104 DM neben den Aufwendungen für die neuen Kamerarechner.

Intracavitary treatment of patients with chronic otitis media or sinusitis by application of 186Re-colloids into the middle ear or the paranasal sinuses, called RTSO, is effective and well tolerated. Clinical improvement is supported by objective data from audiometry, endoscopy, and CT. The method of local irradiation of an inflamed mucosa by β-emitting radionuclides can thus be extended from RSO to otherwise therapy-resistant patients with chronic otitis media and paranasal sinusitis. Compared with other intracavitary treatments, such as irradiation of intracranial cystic tumors, RTSO exerts much less radiation load and does not show any severe side effects. RTSO may overcome the disadvantages of insufficient radiation dose and high invasiveness as seen in former treatment methods using simple X-ray therapy or different applicator tubes.

BACKGROUND: The specificity in discriminating pancreatitis is limited in the positron emission tomography (PET) using Fluorine-18-fluorodeoxyglucose. Furthermore, PET is not widely available compared to the single photon emission computed tomography (SPECT). Since amino acids play a minor role in metabolism of inflammatory cells, the potential of the SPECT tracer, 3-[123I]iodo-L-α-methyltyrosine (123I-IMT), for detecting pancreatic cancer was examined in xenotransplantation models of human pancreatic carcinoma in mice. METHODS: 123I-IMT was injected to eight mice inoculated with subcutaneous or orthotopic pancreatic tumors. Fused high-resolution-micro-SPECT (Hi-SPECT) and magnetic resonance imaging were performed. The gene expression level of L amino acid transport-system 1 (LAT1) was analyzed and correlated with tumor uptake of 123 I-IMT. RESULTS: A high uptake of 123I-IMT was detected in all tumor-bearing mice. The median tumor-to-background ratio (T/B) was 12.1 (2.0-13.2) for orthotopic and 8.4 (1.8-11.1) for subcutaneous xenotransplantation, respectively. Accordingly, the LAT1 expression in transplanted Colo357 cells was increased compared to non-malignant controls. CONCLUSIONS: Our mouse model could show a high 123I-IMT uptake in pancreatic cancer. Fused MRI scans facilitate precise evaluation of uptake in the specific regions of interest. Further studies are required to confirm these findings in tumors derived from other human pancreatic cancer cells. Since amino acids play a minor role in the metabolism of inflammatory cells, the potential for application of 123I-IMT to distinguish pancreatic tumor from inflammatory pancreatitis warrants further investigation.

ZusammenfassungUm ein Verfahren zur Digitalisierung von Analogszintigrammen zu entwickeln, wurden 40 Ganzkörper-Skelettszintigramme simultan in analogem sowie in primär digitalem Format erstellt. Die Analogszintigramme wurden dann mittels dreier verschiedener Techniken sekundär digitalisiert: 300-dpi-Flachbett-Scanning, hochauflösendes Kamera-Scanning und Videokamera-Erfassung. Als optimale Variante erwies sich die Bilderfassung mit handelsüblichem Camcorder, Lichtkasten und PC mit Bilderfassungs-Hard- und Software. Bei der visuellen Interpretation der primär bzw. sekundär digitalisierten Szintigramme fand sich kein Unterschied zwischen beiden Bildformaten. Zusätzlich wurden in beide Bildformatgruppen 126 äquivalente individuelle ROIs gelegt und der relative Radioaktivitätsanteil an der Gesamtkörperaktivität verglichen. Es fand sich eine lineare Korrelation für beide Bildformate. Die sekundäre Digitalisierung von Analogbildern ist eine einfache, zuverlässige, praxisgerechte und kostengünstige Methode zur Bildarchivierung und erlaubt eine sekundäre digitale Quantifizierung.

In this paper an extension of the normalized mutual information is proposed to register standalone obtained low dose CT with already superimposed lung inhalation SPECT and perfusion SPECT images. In order to validate our method, superimposed inhalation SPECT, perfusion SPECT and low dose CT image triples were collected obtained by a hybrid SPECT/CT camera at the same time. A known transformation was applied to the low dose CT to simulate a misalignment, followed by an optimal transformation search performing our extended normalized mutual information-based (eNMI) method. For comparison and evaluation, the low dose CT was also registered to both inhalation and perfusion images one-by-one applying a dual-normalized mutual information-based (dNMI) method. Comparative results have shown that our eNMI method worked with minimal registration error and number of iterations, hence it can be successfully applied to stand alone performed low dose CT - SPECT registrations. I. INTRODUCTION

A method is proposed to process ECD brain SPECT images representing epileptic hot spots inside the brain. For validation 35 ictal —interictal patient image data were processed. The images were registered by a normalized mutual information method, then the separation of the suspicious and normal brain areas were performed by two threshold-based segmentations. Normalization between the images was performed by local normal brain mean values. Based on the validation made by two medical physicians, minimal human intervention in the segmentation parameters was necessary to detect all epileptic spots and minimize the number of false spots inside the brain.

Radiation synovectomy was developed for local treatment of rheumatoid arthritis. In this study, the long-term efficacy of radiation synovectomy was retrospectively evaluated in patients with osteoarthritis (activated arthrosis) of the digital joints using an algofunctional score.Fifty-three digital joints in 29 patients (mean age 64.8 years) were treated by intra-articular injection of 169Er citrate. All joints were painful despite pharmacotherapy and showed an elevated blood pool pattern in a pretherapeutic three-phase bone scan, indicative for local synovitis. The patients were asked to classify their complaints with respect to different daily manual activities on a ten-step pain scale from 1 (total disability) to 10 (lack of any impairment) prior to and after treatment, with a mean follow-up of 41 months. Local signs of osteoarthritis such as joint swelling or pain were additionally evaluated and were scored from progression of complaints to excellent improvement based on patient self-evaluation.All patients reported a pronounced improvement in their manual activities. The mean total score of 4.73+/-0.58 for all activities prior to treatment increased significantly to 6.79+/-0.47 after radiation synovectomy (p0.05). The best results were obtained in the thumb base joints, whereas distal interphalangeal joints were frequently resistant to therapy.Radiation synovectomy is highly effective in digital joint osteoarthritis with concomitant local synovitis.

Transplantation of progenitor cells (PCs) has been shown to improve neovascularization and left ventricular function after myocardial ischemia. The fate of transplanted PCs has been monitored by fluorescence labeling or by genetic modifications introducing reporter genes. However, these techniques are limited by the need to kill the experimental animal. The aim of this study was to radiolabel CD34(+) hematopoietic PCs (HPCs) with (111)In-oxine and to evaluate the feasibility of this in vivo method for monitoring myocardial homing of transplanted cells in a rat myocardial infarction model.Human HPCs were isolated from mobilized peripheral blood and labeled with (111)In-oxine. Labeled HPCs were injected into the cavity of the left ventricle in nude rats 24 h after induction of myocardial infarction (n = 4) or sham operation (n = 4). Scintigraphic images were acquired up to 96 h after HPC injection. After animals were killed, tissue samples of various organs were harvested to calculate tissue-specific activity and for immunostaining.Labeling efficiency of HPCs was 32% +/- 11%. According to trypan-blue staining, viability of radiolabeled HPCs was impaired by 30% after 48 and 96 h in comparison with unlabeled cells, whereas proliferation and differentiation of HPCs was nullified after 7 d, as assessed by colony-forming assays. After injection of HPCs, the specific activity ratio of heart to peripheral muscle tissue increased from 1.10 +/- 0.32 in sham-operated rats to 2.47 +/- 0.92 (P = 0.020) in infarcted rats. However, the overall radioactivity detected in the heart was only about 1%. A transient high lung uptake of 17% +/- 6% was observed within the first hour after infusion of HPCs. At 24 h after injection, the initial lung activity had shifted toward liver, kidneys, and spleen, resulting in an increase of radioactivity in these organs from 37% +/- 6% to 57% +/- 5%.Radiolabeling with (111)In-oxine is a feasible in vivo method for monitoring transplanted HPCs in a rat myocardial infarction model. The potential to detect differences in myocardial homing between infarcted and normal hearts suggests that this method may provide a noninvasive imaging approach for clinical trials using transplanted HPCs in patients. Our findings, however, also demonstrated a negative effect of (111)In-oxine on cellular function, which resulted in complete impairment of HPC proliferation and differentiation. For future trials in stem cell imaging with (111)In-oxine, therefore, it will be mandatory to carefully check for radiation-induced cell damage.

The aim of this study is to investigate the myeloprotective effects of different amifostine regimens in rabbits undergoing high-dose treatment with 186Rhenium-(tin)1,1-hydroxyethylidene diphosphonate (186Re-HEDP) and to analyze the impact of amifostine on the bone uptake of the radiopharmaceutical. All animals were treated with 1000 MBq 186Re-HEDP. Group ReA received 500 mg amifostine prior to radionuclide therapy, group ReA3 received 3 x 200 mg amifostine 24 hours and 30 minutes prior to and 24 hours after radionuclide therapy. Group ReC served as control receiving no amifostine. Scintigrams were acquired to quantify the skeletal uptake of 186Re-HEDP, and platelet and leucocyte counts were measured. The mean decrease in platelets was 36% +/- 2%, 37% +/- 3%, and 61% +/- 5% for ReA, ReA3, and ReC, respectively. The decrease in ReC was significantly higher than in amifostine-treated animals with no difference between ReA and ReA3. For the leucocytes the mean decrease was 75% +/- 12%, 82% +/- 5%, and 73% +/- 4%, with no significant differences between the respective groups. Bone uptake of 186Re-HEDP was significantly reduced by 50% in ReA and ReA3 compared to ReC. Thus, the 3-day amifostine regimen had no advantage over the single dose regimen, with both regimens reducing bone uptake and yielding a platelet-protective but no leucoprotective effect.

Accurate knowledge of lymphatic drainage facilitates planning of surgery for patients with squamous cell carcinoma of the head and neck. The aim of this study was to evaluate the feasibility of a new injection technique for lymph node detection in patients with squamous cell carcinoma of the hypopharynx and larynx, in whom simple peritumoural injection is hampered by the tumour localisation. Computed tomography (CT)-guided lymphoscintigraphy was performed in a total of 13 patients with squamous cell carcinoma of the hypopharynx and larynx who could not be injected by simple visual inspection. In a first step, contrast medium-enhanced axial 5-mm-thick CT slices of the neck were obtained. After tumour localisation on these CT images, 1–2 ml contrast medium and, in the event of appropriate distribution, subsequently 50 MBq technetium-99m colloid were injected at one to three peritumoural sites under CT guidance. Peritumoural tracer distribution was controlled by thin-slice CT. Subsequently, planar scintigrams from anterior, right and left lateral views were obtained. In all patients, peritumoural colloid application was feasible, as shown on control CT scans. Post injection, neither severe nor minor complications were noted. The patients complained of only low pain sensations with an average score of 1.8 on a pain scale from 0 to 10. Lymphatic drainage was identified in nine of the 13 patients, with a total of 14 detected lymph nodes. In six patients, ipsilateral sentinel lymph nodes were visualised; bilateral sentinel lymph nodes were identified in one patient and contralateral lymphatic drainage was observed in two patients. CT-guided lymphoscintigraphy is a feasible and minimally invasive diagnostic tool for sentinel lymph node detection in patients with squamous cell carcinoma of the hypopharynx and the larynx. In contrast to endoscopic colloid injection under general anaesthesia, this technique seems to be a well-tolerated method for lymphatic mapping prior to surgical procedures.

Background— Transplantation of endothelial progenitor cells (EPCs) improves vascularization and left ventricular function after experimental myocardial ischemia. However, tissue distribution of transplanted EPCs has not yet been monitored in living animals. Therefore, we tested whether radioactive labeling allows us to detect injected EPCs. Methods and Results— Human EPCs were isolated from peripheral blood, characterized by expression of endothelial marker proteins, and radioactively labeled with [ 111 In]indium oxine. EPCs (10 6 ) were injected in athymic nude rats 24 hours after myocardial infarction (n=8) or sham operation (n=8). Scintigraphic images were acquired after 1, 24, 48, and 96 hours after EPC injection. Animals were then killed, and specific radioactivity was measured in different tissues. At 24 to 96 hours after intravenous injection of EPCs, ≈70% of the radioactivity was localized in the spleen and liver, with only ≈1% of the radioactivity identified in the heart of sham-operated animals. After myocardial infarction, the heart-to-muscle radioactivity ratio increased significantly, from 1.02±0.19 in sham-operated animals to 2.03±0.37 after intravenous administration of EPCs. Injection of EPCs into the left ventricular cavity increased this ratio profoundly, from 2.69±1.54 in sham-operated animals to 4.70±1.55 ( P Conclusions— Although only a small proportion of radiolabeled EPCs are detected in nonischemic myocardium, myocardial infarction increases homing of transplanted EPCs in vivo profoundly. Radiolabeling might eventually provide an useful tool for monitoring the fate of transplanted progenitor cells and for clinical cell therapy.

The aim of this animal study was to measure the bone uptake of (99m)Tc-hydroxymethylene diphosphonate (HDP) before and after high-dose treatment with (153)Sm-ethylenediaminetetramethylenephosphonate (EDTMP) or (186)Re-(tin)1,1-hydroxyethylidene diphosphonate (HEDP) to prove or disprove post-therapeutic alterations of bone uptake of radiolabeled bisphosphonates.Quantitative bone scanning using 100 MBq (99m)Tc-HDP was performed on 12 rabbits before and 8 wk after radionuclide therapy with 1,000 MBq of either (153)Sm-EDTMP or (186)Re-HEDP. Whole-body images were acquired at 3 min, 3 h, and 24 h after injection, and the activities for the whole body, urinary bladder, and soft tissue were measured by region-of-interest technique. From these data, bone uptake was calculated as initial whole-body activity minus urinary excretion and remainder soft-tissue activity.In animals treated with (153)Sm-EDTMP (n = 6), no differences could be proven for the bone uptake of (99m)Tc-HDP at 24 h after injection before and after therapy (51.1% +/- 5.5% vs. 48.0% +/- 6.1%, P0.05). There were also no significant differences for the remainder soft-tissue activities and the urinary excretion rates before and after therapy. Similar results were obtained in rabbits treated with (186)Re-HEDP: Bone uptake (44.8% +/- 6.7% vs. 40.4% +/- 4.9%, P0.05) and urinary excretion revealed no significant differences before and after treatment.No significant impairment of bone uptake of (99m)Tc-HDP could be observed 8 wk after high-dose radionuclide bone therapy. Because both the biokinetic data obtained for (186)Re-HEDP and (153)Sm-EDTMP and the myelotoxic effects were quite similar in rabbits to those in patients, it seems justifiable to expect the same result (i.e., no significant alteration of bone uptake of radiolabeled bisphosphonates) in patients undergoing a second radionuclide therapy within 2-3 mo after standard treatment with (186)Re-HEDP or (153)Sm-EDTMP.

Radiation synovectomy by intra-articular injection of beta-emitting radionuclides is a reliable and easy-to-perform therapy without harmful side effects for the treatment of inflammatory rheumatoid as well as degenerative joint diseases. The indication for radiation synovectomy is based on both clinical symptoms and on proven hyperperfusion, with active synovitis being seen on a pre-therapeutic three-phase bone scan. In this study, the clinical response after 6-18 months, evaluated by a standardized questionnaire, was compared with the reduction of synovitis seen on three-phase bone scintigraphy after treatment of 475 joints in 151 patients. The best clinical results were obtained in cases of true rheumatoid arthritis (73.4%), with less in other kinds of arthritis (48.8%) such as psoriatic or reactive arthritis. Because of the inflamed synovium being the main target tissue, clinical results in osteoarthritis with severe bone destruction are poorer (33.9%). However, synovitis can be markedly reduced (in approximately 70%), regardless of the underlying diagnosis, as shown by post-therapeutic three-phase bone scanning. Radiation synovectomy can be recommended in all kinds of arthritis. It should also be considered in cases of osteoarthritis as a last therapeutic option prior to joint replacement.

Impairment of salivary gland function following high-dose radioiodine treatment (HDRIT) is a well-recognized side effect of the treatment. Because differentiated thyroid cancer has an excellent prognosis, reduction of long-term side-effects is mandatory. Therefore, the aim of this study was to investigate the radioprotective effect of amifostine in a rabbit animal model.Salivary gland scintigraphy was performed in a total of 16 New Zealand White rabbits. Uptake of 99-Tc-pertechnetate was calculated in percentage of injected activity as a quantitative measure of both salivary gland and thyroid function. Reproducibility of salivary gland scintigraphy was evaluated in one rabbit without any intervention. Fifteen rabbits were studied prior to and up to 6 months after high-dose radioiodine treatment applying 2 GBq 131I. Ten animals received 200 mg/kg amifostine prior to high-dose radioiodine therapy, and 5 served as controls. Salivary glands were examined histopathologically.Variation coefficient of parenchymal function was less than 3.8% in salivary glands. Prior to HDRIT, thyroid uptake was 0.417+/-0.373% and 0.421+/-0.241% in control and amifostine-treated rabbits, respectively. Four weeks after HDRIT, complete ablation of the thyroid was achieved in both groups. Prior to HDRIT, uptake of 99mTc-pertechnetate in salivary glands of five control rabbits was not significantly different from ten amifostine-treated rabbits. In control rabbits 6 months after HDRIT, parenchymal function was reduced significantly (p0.0001) by 75.3+/-5.3% and 53.6+/-17.4% in parotid and submandibular glands, respectively. In contrast, in amifostine-treated rabbits, parenchymal function was reduced by 10.6+/-3.4% and 6.5+/-4.3% (p0.05) in parotid and submandibular glands, respectively. Histopathologically, marked lipomatosis was observed in control animals but was negligible in amifostine-treated animals.Parenchymal damage in salivary glands induced by high-dose radioiodine treatment can be significantly reduced by amifostine in this rabbit animal model. This corresponds to data obtained in patients with differentiated thyroid cancer.

The serum detection of S100B, a new melanoma marker, has shown clinical significance in early studies. The aim of our study of 1,339 serum samples from 412 different melanoma patients and 107 control patients was to prove the prognostic value of serum S100B levels in melanoma patients at different stages of disease and at follow-up (median: 30 months). Using a cutoff level of 0.2 μg/l S100B, 5 of 286 patients (1.7%) with primary tumors (stage I/II), 14/73 (19.2%) patients with locoregional metastasis (stage III) and 57/84 (67.9%) patients with advanced disease (stage IV) were S100B positive (statistically significant differences for stage I/II vs. III, I/II vs. IV, and III vs. IV, p < 0.001). The estimated overall survival time was significantly longer (p < 0.001) for patients with S100B values below 0.2 μg/l compared to patients with elevated S100B levels (≥0.2 μg/l), which was independent of the stage of disease (I–IV). Regarding prognosis, we were furthermore able to distinguish different subgroups among stage III and IV patients using S100B serum levels (p < 0.01). Patients with different cutaneous non-melanoma diseases served as S100B-negative controls. S100B serum evaluations using the Sangtec®100 IRMA are highly specific and sensitive for the detection of metastatic melanoma. S100B has been shown to be a relevant prognostic factor for survival in a study with a large sample size of melanoma patients including close follow-up evaluations.

Since knowledge of possible lymphatic drainage may facilitate preoperative planning a method of lymphoscintigraphy with exact correlation of lymphatic drainage to six known cervical compartments is presented. 78 patients with various tumors of the head and neck received 100 MBq Tc-99m-colloid in 3–4 peritumoral sites. 2 ml of perchlorate solution were given orally in order to block the thyroid. Patients received 50 MBq Tc-99m-pertechnetate i.v. for body-contouring 20 min p.i. Planar images were obtained over 5 min each at 30 min and 4–6 h after injection from anterior, right lateral and left lateral using a LFOV-gamma camera. The thyroid was seen in any of the patients. In 28/78=36 % of the patients the injection site was the only focal activity seen. In 50/78=64 % of the patients lymphatic drainage could be observed: 36/78=46 % showed unilateral, and 14/78=18 % exhibited bilateral lymphatic drainage. In all 50 patients showing lymphatic drainage lymph nodes could be easily assigned to the six cervical lymph node compartments described. Accurate correlation of lymphatic drainage and cervical compartments yields the basis for a re-evaluation of its impact in preoperative planning of different procedures of neck dissection.

To evaluate the usefullness of bone scanning in hemimandibular elongation (HE) 22 patients underwent bone scanning prior to surgery. Activity of growth was quantified by calculating a L/R ratio. Correcting osteotomy (CO) was performed in patients showing L/R 1.10 underwent condylectomy (CE). 20 patients showed L/R< 1.10. In 13 of them a CO was performed without any relapse. 2 patients showed marked unilateral increased uptake. In one patient bone scan was not considered, and CO was performed with subsequent recurrence of laterognathia. The other patient underwent CE without any relapse. In conclusion, bone scanning has significant clinical value in preoperative decision-making in HE.

The aim of this study was to label various anthracyclines (doxorubicin, iododoxorubicin, daunorubicin) with I-123, and to determine their uptake both in sensitive and anthracycline-resistant tumour cell cultures compared to the standard [C-14]DOX. Three of the four anthracyclines showed different uptake in both cell lines. The uptake in resistant cells seems to be independent of the chemical structure of the anthracyclines, whereas the uptake in sensitive cells was affected by iodination.

To evaluate the usefulness of somatostatin receptor scintigraphy (SRS) in patients with suspected meningeoma, 58 patients were investigated prior to surgery receiving standard MRI and SRS following i.v. injection of 200 MBq In-111-octreotide. SRS was true positive in 44/58, true negative in 5 neurinoma, and false negative in 9 patients. In the latter tumor volume was < 10 ml. MRI was decisive for meningeoma in 39/58 patients. In 14/58 patients MRI could not differentiate between meningeoma and neurinoma. Of these, positive SRS confirmed meningeoma in 9 patients, and negative SRS excluded meningeoma in the remaining 5. In conclusion, SRS has significant clinical impact in patients with suspected meningeoma following MRI.

This study was designed to quantitatively investigate the ventilation of the middle ear and the paranasal sinuses by using Xe-133 gas. In all patients both maxillary sinuses could be visualized revealing consistent clearance data while only in 19 out of 30 patients tracer accumulation in the tympanum was observed with a large range of clearance half-life. These findings clearly represent the different physiological conditions of the ventilation of the maxillary sinuses and the tympanum. Ventilation studies with Xe-133, therefore, are useful for quantitative evaluation and may be easily obtained for maxillary sinuses, while uptake and clearance in the tympanum are hampered by the involved physiological mechanisms.

A virtually planar water tetramer in which the water molecules are virtually tetrahedrally coordinated could be realized in the solid in a three-dimensional network of [Tc4(CO)12-(mu3-OH)4.4H2O]. The network could be produced by cocrystallization of the new cubane-like cluster [Tc(CO)3-(mu3-OH)]4 and water as a complementary component. The amphiphilic behavior of cluster and water results in a highly ordered three-dimensional network. The complementary components, the water tetramer and the cubic cluster, independently of one another form two interpenetrating tetragonal lattice networks held together exclusively by hydrogen bonds.

Dynorphin A (1–10) was radioiodinated directly via electrophilic substitution of the reactive tyrosine. The uptake of this labelled dynorphin in glioma cell cultures was measured. Tracer uptake was compared with the non-specific tumour tracer T1-201. TI-201 showed a time independent uptake over the whole incubation time of 4 hours. In contrast, increasing accumulation of radioactivity was found with I-125 labelled dynorphin. The increasing uptake over time may be evidence for a specific binding process with a possible potential for receptor imaging in man.

Malignant struma ovarii is a very rare disease and, therefore, there is neither common agreement on treatment regimens nor sufficient follow-up experience. We present a case of a 49-year-old woman with malignant struma ovarii of the follicular type, who received ablative radioiodine treatment after thyroidectomy and surgical removal of the primary tumour. During follow-up examinations an increasing thyroglobulin level was found, caused by a tumour relapse with suspected urinary bladder infiltration on CT and proven uptake of radioiodine on whole-body scanning with iodine-131. After administration of 6GBq 131I, complete tumour regression was achieved with no evidence of a new relapse during a 30-month follow-up period. Correspondingly, repeated thyroglobulin measurements were all negative. This case demonstrates the benefit of combined surgical and radioiodine treatment of malignant struma ovarii for both monitoring and therapy of relapse or metastases; thus, the same therapeutic regimen as is employed in primary differentiated thyroid carcinoma may be recommended.

The aim of this study was to evaluate somatostatin receptor scintigraphy (SRS) in patients with suspected meningeoma. Prior to surgery 59 patients were investigated up to 24 h following an injection of 200 MBq In-111-octreotide. Tracer uptake was tested for the presence of meningeoma. Histology revealed 43 meningeoma and 16 other tumours. True positive SRS was obtained in 36 patients. Tumour volume was > 10 ml in 23 patients. False negative SRS was seen in 7 patients. All of them had a tumour volume of < 10 ml. While magnetic resonance imaging (MRI) alone was decisive in 39 of 48 patients, MRI could only limit differential diagnosis to meningeoma versus neurinoma in the remaining 9 patients. Out of these, positive SRS confirmed meningeoma in 5 patients, and negative SRS excluded meningeoma in 4 patients. In conclusion, there is significant clinical benefit of functional imaging with In-111-octreotide in patients with suspected meningeoma: Large meningeoma can be excluded by scintigraphy alone, while meningeoma of any size may be confirmed in combination with specific MRI results only.

In this study an attempt was made to administer radioactive gas into the tympanic cavity of 15 otolaryngology-patients and to measure the initial gas trapping as well as the wash out from the middle ear to quantify the function of the Eustachian tube. 50 MBq of Xenon-133 were applied into the pharynx followed by Valsalva’s maneuver and the gas could successfully be traced in the tympanum of all patients. The normal right-to-left uptake ratio ranged from 2.1 to 0.5 (median: 1.0) and the normal half life from 11.5 min to 217.9 min (median: 96.2). Thus, middle ear ventilation scintigraphy proved to be an easy-to-perform and very low radiation-exposure test for evaluating Eustachian tube function.

Since verapamil has been shown to increase cellular concentrations of anthracyclines in resistant tumor cells, this study was designed to investigate the impact of verapamil on myocardial accumulation of I-123 labelled doxorubicin (DOX) and iodo-doxorubicin (IDOX) in rabbits and to estimate the risk of increasing anthracycline-related cardiotoxicity. Cardiac accumulation of both DOX and IDOX, calculated by scintigraphic means, neither confirmed major differences due to prior administration of verapamil nor an increased risk of cardiotoxicity of DOX and IDOX in combination with verapamil, respectively.

To investigate tumour cell resistance in vitro uptake measurements of I-123-labelled IDOX were performed in tumour cell lines of gastric carcinoma being sensitive and resistant to anthracyclines. In sensitive gastric carcinoma cells an increasing uptake with time amounting to 0.94% of acivity applied was found, thus being 5.3 times higher than T1-201 accumulation. In contrast, in resistant gastric carcinoma accumulation was in the range of Tl-201 accumulation. Thus, in gastric carcinoma drug resistance effectivly diminishes uptake of I-123-IDOX.

The background slope in renal function studies with radioiodine-hippuran is a factor for plasma clearance estimations. A slope derived from a camera background ROI may be contaminated by renal scatter. In consequence, the slope will be flattened in patients with obstructive uropathy. Therefore, a scatter image (window: 120 keV ± 32%) was used for correction. The effect of delayed renal elimination on the slope is minimized by subtracting an appropriate fraction of this scatter data from the original peak data. Simultaneously the correlation coefficient and the standard error of the estimate improve. Thus, compensation by scatter correction during renal function studies is feasible and may be clinically useful.

The aim of this study was to label iodo-doxorubicin (IDOX), a new anthracycline derivative, with I-123, and to determine its uptake both in sensitive and anthracyclineresistant tumour cell cultures compared to the unspecific tumour tracer TI-201. Iodinated iododoxorubicin showed different uptake in both cell lines. In addition pharmacokinetics of I-123IDOX was described in vivo in rabbits, revealing a myocardial uptake of labelled IDOX similar to T1-201-uptake.

Direct noninvasive measurements of isodose distribution was not possible yet in brachytherapy. By using a gamma camera with SPECT imaging, we measured Compton photons scattered by tissue interaction in order to quantify isodose distribution resulting from a Low-dose-Ir-192-source (45 mCi). The effective local tissue dose seems to correlate to the isocount rate.