[18Fluoro-FDG SPECT for the demonstration of hibernating myocardium: an interim account]. / 18Fluor-FDG-SPECT zum Nachweis von hibernierendem Myokard: eine Zwischenbilanz.

AIM: The present investigation demonstrates an intraindividual comparison of FDG-PET and FDG-SPECT. MATERIAL AND METHODS: Thirty patients with CHD and planed revascularisation underwent both modalities. Myocardial perfusion was evaluated by 99mTc-MIBI SPECT. The myocardium was divided into 25 segments and the results were compared by two experienced observers. RESULTS: Segmental concordance of FDG-PET and -SPECT was 94.1%. PET indicated a higher percentage of hibernating myocardium (8.9% vs. 5.7%) and a lower rate of matched defects (11.5% vs. 16.0%). In 22 cases the need for revascularisation was assessed identically. In the remaining 8 patients FDG-PET and FDG-SPECT required an intervention in 6 and 2 cases, respectively. CONCLUSION: The results of FDG-PET and FDG-SPECT showed a high segmental concordance, but the individual assessment of hibernation worthwhile for revascularisation demonstrated important differences in patient management.

[Palliative treatment for pain in osseous metastasized prostatic carcinoma with osteotropic rhenium-186 hydroxyethylidene diphosphonate (HEDP)]. / Palliative Schmerztherapie beim ossär metastasierten Prostatakarzinom mit dem osteotropen beta-Strahler 186Rhenium-Hydroxyethylidendiphosphonat (HEDP).

Systemic administration of strontium-89 is an important option for pain relief in advanced prostate carcinoma with multiple osseous metastases. Recently, rhenium-186-HEDP was introduced as a new substance which has important advantages (shorter physical half-life, scintigraphic imaging, dose distribution). The myelosuppressive effect can be estimated more accurately in advance, so that adverse effects can be reduced and the treatment can be repeated after a shorter period of time and more often. Our study comprises 15 treatments with rhenium-186-HEDP in advanced prostate cancer patients using the 1.4- to 2-fold standard dose. The response rate, estimated as reduction in pain and increase in patient mobility, was 87% with no major myelosuppressive effects. The mean duration of pain relief was 4-6 weeks. All four patients with repeated therapy were also responding to the second treatment. Radionuclide therapy for painful osseous metastases with rhenium-186-HEDP appears to be an effective and, even at higher doses, safe procedure.

Investigations of breast tumors with fluorine-18-fluorodeoxyglucose and SPECT.

METHODS: We designed a prospective study to investigate the feasibility of combined FDG-SPECT and whole-body acquisition in the diagnostic work-up of breast tumors applying visual analysis. We studied 50 patients with breast tumors of unknown histology. RESULTS: All malignant diseases were accurately detected in tumors > 2.3 cm, while the smallest FDG-positive lesion was 1.4 cm. In a subgroup of these patients, quantitative evaluation (tumor-to-back-group ratios) was added, which improved the sensitivity. Lymph node metastases were accurately indicated in 9 of 13 patients, while the detection of distant metastases depended on the location and size. False-positive FDG scans were observed in inflamed tissue, in a rapidly growing phylloides tumor and in supposedly healthy breasts. CONCLUSION: These results are comparable with prior investigations of other groups using PET. Therefore, FDG-SPECT and whole-body acquisition may be an adequate and less expensive technique to meet the increasing demand of FDG examinations.

Granulocyte labelling kit BW 250/183--results of the European multicenter trial.

In 6 European countries a multicenter trial with the technetium-99m labelled monoclonal anti-granulocyte antibody BW 250/183 was conducted in 775 patients. The antibody is used for the immunoscintigraphic visualisation of accumulations of granulocytes. The present study was restricted on the investigation of patients having inflammations, essentially of the peripheral skeleton (mostly of the lower extremities), spinal column, the bowel, or had fever of unknown etiology. The overall sensitivity of the method was 83%, and specificity was of the same order of magnitude (82%). The procedure yielded additional information in 67% of the cases and the treatment strategy was influenced in 35% of the cases to positive effect, even though all conventional methods had previously been exhausted. Human anti mouse-IgG antibodies (HAMA) were detectable only in about 4% of patients investigated for the first time.

Anti-CEA labelling kit BW 431/26. Results of the European multicenter trial.

In seven European countries a multicenter trial with the 99mTc-labelled monoclonal anti-CEA antibody BW 431/26 was conducted in 730 patients. The antibody is used for the immunoscintigraphic visualisation of CEA-expressing tumours. Investigated were in particular colorectal tumours, bladder and breast carcinoma, medullary thyroid carcinoma, adenocarcinoma of the lung and gastric carcinoma. The main area of use is the detection of recurrences and screening for foci in patients with rising serum CEA. The sensitivity amounts to at least 80% in case of primary colorectal tumours (n = 129) and their abdominal or pelvic metastases (n = 33) and to 90% for their recurrences (n = 107). HAMAs were detectable in less than 15% of patients investigated for the first time. In 17% of the patients examined, immunoscintigraphy was the only technique to visualize the lesion whereas all other diagnostic methods had failed. The procedure yielded additional information in 24-51% of cases.

Radioimmunoscintigraphy of ovarian tumours with technetium-99m labelled monoclonal antibody-170: first clinical experiences.

The recently developed technetium-99m-labelled monoclonal antibody-170 (MAb-170) was designed for diagnostic use in patients suffering from gynaecological adenocarcinoma. Following in vitro studies which showed immunoreactivity of this antibody to more than 90% of human adenocarcinomas, the present investigation was initiated to verify its usefulness for radioimmunoscintigraphy of ovarian tumours. Most of the 30 patients participating in this study underwent immunoscintigraphy prior to first-look surgery. Biokinetic evaluation in two patients showed a plasma half-time of 18.9 h (mean value, n = 2, r = 0.98) and a biexponential total body curve with values of 7.7 h and 17 days (r = 0.98). The mean 24-h urinary excretion was 12% of the injected dose. Radioimmunoscintigraphy using the MAb-170 recognised 12 of 13 cases of adenocarcinoma of the ovaries, corresponding to an overall sensitivity of 92.3%. Specificity was 94.1% (16/17). The calculation of accuracy yielded a figure of 93.3% (28/30). Of 33 known lesions, 26 were visualised successfully; thus the locoregional sensitivity was 78.8%. Of 29 benign tumour sites, 28 showed no evidence of tracer accumulation, corresponding to a locoregional specificity of 96.6%. The smallest lesion visualised was an adenocarcinoma of the corpus uteri with a diameter of 1.5 cm. Technetium-99m labelled MAb-170 is a promising new radiopharmaceutical for immunoscintigraphy of ovarian adenocarcinoma.

[18FDG in the primary staging of lung tumors. Results with a gamma camera and a 511 keV collimator]. / 18FDG beim primären Staging von Lungentumoren. Ergebnisse an einer Gammakamera mit einem 511 keV Kollimator.

The diagnosis of primary lung tumors requires a precise staging according to the TNM classification. In contrast to established imaging methods 18FDG describes the functional metabolic processes in the tumor tissue due to increased glycolysis. This paper describes the use of 18FDG in the primary staging of lung tumors and metastases. 44 patients were studied with a gamma camera and a 511 keV collimator. In comparison to pulmonary tumors and metastases detected by other imaging methods (107) the accumulation of 18FDG has a sensitivity of 85%, in lesions verified by histology (50) of 89%, in primary tumors (35) of 100% and in metastases (63) of 76%. As an alternative to FDG PET studies, primary staging of lung tumors is possible with a gamma camera, suitable for ECT and fitted with a 511 keV collimator.

Myocardial scintigraphy.

Nuclear cardiology continues to be of particular importance in nuclear medicine. In this domain, myocardial scintigraphy has become the eminent diagnostic tool in the diagnosis of cardiac disorders like coronary artery disease, myocarditis, heart transplant rejection, chemotherapy-induced cardiotoxicity, and others. In a comparison of the latest worldwide trends, European investigators seem to be more interested in recently developed myocardial tracers than those in the US. Besides research into antimyosin monoclonal antibodies for the detection of myocardial damage, the technetium 99m-labeled perfusion markers are being studied as potential substitutes for thallous chloride TI 201. In recent years, the dual use of 201TICI/99mTc-sestamibi taught us the comparable clinical value of these two radiopharmaceutics in the detection of coronary artery disease. In the future, additional 99mTc-labeled perfusion markers may contribute to the ongoing decrease in thallium's widespread use. In the area of viability (ie, the preinterventional detection of potentially reversible myocardial wall-motion abnormalities), 201TICI is still not fully accepted. The most reliable diagnostic tool for this procedure is 13N-NH3 (ammonia)/fluorine F18 fluorodeoxyglucose (FDG) positron emission tomography because of its options for quantification and high-resolution imaging. In the near future, the limited number of these sophisticated but expensive positron emission tomography centers will not satisfy the growing clinical demand for viability studies. Thus, European nuclear cardiologists are developing alternative techniques for positron imaging. They have shown that by means of a conventional gamma camera with special high-energy collimators, a reliable perfusion/viability assessment is feasible.(ABSTRACT TRUNCATED AT 250 WORDS)

[Performance of a multispect 2 gamma camera for imaging 511-keV gamma rays]. / Testmessungen an der Multispect-2-Gammakamera zum Nachweis von 511-keV-Gammastrahlung.

The performance of a modified Multispect 2 gamma camera, which was supplied with two pairs of collimators constructed for imaging positron emitters was tested. The measurements involved the determination of sensitivity and of spatial resolution. The septal penetration was calculated approximately using two different methods. The spatial resolution determined by FWHM as measured by planar imaging in water at 10 cm distance from the collimator was evaluated as 14.0 mm with collimator 511-A and 12.5 mm with collimator 511-B. Using a Gaussian fit of the line-spread function septal penetrations of 12% with collimator 511-A and of 36% with collimator 511-B were calculated. The absolute system sensitivity measured with 18F was 66 cpm with collimator 511-A and 98.7 cpm/37 kBq with collimator 511-B. The high sensitivity with collimator 511-B may be explained, at least partially, by the high septal penetration.

Myocardial metabolic imaging by means of fluorine-18 deoxyglucose/technetium-99m sestamibi dual-isotope single-photon emission tomography.

The detection of preserved glucose uptake in hypoperfused dysfunctional myocardium by fluorine-18 deoxyglucose (FDG) positron emission tomography (PET) represents the method of choice in myocardial viability diagnostics. As the technique is not available for the majority of patients due to cost and the limited capacity of the PET centres, it was the aim of the present work to develop and test FDG single-photon emission tomography (SPET) with the means of conventional nuclear medicine. The perfusion marker sestamibi (MIBI) was used together with the metabolic tracer FDG in dual-isotope acquisition. A conventional SPET camera was equipped with a 511-keV collimator and designed to operate with simultaneous four-channel acquisition. In this way, the scatter of 18F into the technetium-99m energy window could be taken into account by a novel method of scatter correction. Thirty patients with regional wall motion abnormalities at rest were investigated. The results of visual wall motion analysis by contrast cine-ventriculography in nine segments/heart were compared with the results of quantitative scintigraphy. The scintigraphic patterns of MIBI and FDG tracer accumulation were defined as normal, matched defects and perfusion-metabolism mismatches. Spatial resolution of the system was satisfactory, with a full width at half maximum (FWHM) of 15.2 mm for 18F and 14.0 mm for 99mTc, as measured by planar imaging in air at 5 cm distance from the collimator. Image quality allowed interpretation in all 30 patients. 88% of segments without relevant wall motion abnormalities presented normal scintigraphic results. Seventy-five akinetic segments showed mismatches in 27%, matched defects in 44% and normal perfusion in 29%. We conclude that FDG-MIBI dual-isotope SPET is technically feasible with the means of conventional nuclear medicine. Thus, the method is potentially available for widespread application in patient care and may represent an alternative to the 201Tl reinjection technique.

[Nuclear medicine diagnosis of focal liver lesions]. / Nuklearmedizinische Diagnostik fokaler Leberläsionen.

Confirmation and exclusion of benign focal liver lesions are the main object of liver studies in nuclear medicine. Hepatobiliary sequence scintigraphy (focal nodular hyperplasia, adenoma), blood pool scintigraphy (hemangioma) and, in some cases, colloid scintigraphy are the methods most frequently employed. Receptor scintigraphy with octreopeptides, immunoscintigraphy with monoclonal antibodies, PET and gamma camera scintigraphy with 18FDG, are used to solve special diagnostic problems, particularly in oncology. A stepwise diagnostic approach needs to be used for a successful classification of focal liver lesions and an extensive knowledge of indications for additional supplementary diagnostic procedures is required.

[A clinical evaluation of MAb BW 835/6 in breast and ovarian cancer]. / Klinische Prüfung mit MAk BW 835/6 bei Mamma- und Ovarialkarzinomen.

Studies with the 99mTc-labeled murine monoclonal antibody BW 835/6 in patients suspected of breast (n = 7) or ovarian cancer (n = 8) showed insufficient depiction of primary tumors and metastases of breast cancer, but promising results in the detection of primary tumors in ovarian cancer without metastases. The small number of patients does not allow statistical analysis.

Monoclonal antibody BW431/26 labelled with technetium 99m and indium 111: an investigation of the biodistribution and the dosimetry in patients.

As a competitive diagnostic tool for the detection of malignant tumours and other pathological conditions, monoclonal antibodies have long been established. Herein we give the biokinetic data of the antibody BW 431/26 and the consequent radiation dose to patients. These parameters were recorded in 39 patients, using the antibody labelled either with technetium 99m or indium 111. Remarkable differences were observed between the two radionuclides. Whereas the indium-labelled one showed biexponential elimination kinetics, the technetium-labelled one is eliminated linearly over time. The distribution pattern of the two is identical, although the radiation dose varies quite a lot, being 20-fold higher with indium 111 when total body exposure is taken into account (for 111In the whole-body radiation exposure is 0.1 mGy/MBq; for 99mTc it is 0.0047 mGy/MBq). With respect to these results and considering the general availability of the technetium-labelled Ab, it is the best choice for diagnostic use.

[Determination of cerebral blood flow using an 81Rb/81mKr generator system]. / Bestimmung des zerebralen Blutflusses mittels des 81Rb/81mKr-Generatorsystems.

A method is being developed which not only measures cerebral blood flow as a static quantity but also its changes with time. For that purpose a semiconductor device ascertains the proportion of intracerebral 81 Rb and 81mKr activities. By opening the hemato-encephalic barrier in animal experiments a sufficient concentration of intracerebral 81 Rb could be attained and the modified blood circulation after step-wise ligature of all brain arteries brought into relation to the corresponding Rb/Kr quotient. Over the range from undisturbed to completely interrupted cerebral blood flow this quotient varied up to 25% of its initial value.

[Nuclear medicine assessment of renal function in beagles before and after extracorporeal percutaneous lithotripsy with a piezoelectric instrument system]. / Nuklearmedizinische Nierenfunktionsprüfung an Beagle-Hunden vor und nach extrakorporaler perkutaner Lithotripsie mit einem piezoelektrischen Gerätesystem (EPL).

High energy sound pulses which are generated piezoelectrically can be used for extracorporal lithotripsy as an alternative to shock-waves. Since several years a lithotripter for renal concrements based on piezoelectrical oscillators has been developed at the Department for Urology in Homburg/Saar; W.Germany. The present paper describes animal experiments which have been carried out with Beagle-dogs in order to prove that the sound pulses used for lithotripsy do not affect renal function. This function is measured by methods of nuclear medicine (131J-Hippuran Clearance with a modified evaluation). In addition it is evaluated by 111In labelled leucocytes if inflammatory processes in the kidney are suspected. It could be demonstrated that no detremental effects on the kidneys can be detected even with the most sensitive methods of nuclear medicine.