[Nuclear medicine in Germany: a look back at the beginning]

The development of nuclear medicine in Germany from early approaches with 32P and 131I to the first radioiodine therapy of thyroid cancer up to the clarification of basic principles for current thyroid diagnostics and for functional scintigraphic imaging are presented. Selected references are used in portraying scientific stepping stones of our speciality as well as its establishment in clinical practice during the first two decades. Researchers, places, and facts are specified and interpreted in their relation to the state-of-the-art of nuclear medicine.

Magnetic resonance (MR) imaging of prostatic tumours, a comparison with X-ray CT and transrectal sonography (TRS)

A total of 7 healthy volunteers and 31 patients have been examined clinically, by MRI, TRS, and biopsy. In those patients with established carcinoma, a CT examination was also performed. For the MRI study, a superconducting MR 2000 imager (Picker International) operated at 0.15 T was used with multiplanar SE and IR sequences. SE sequences with long echo times detected prostatitis, adenoma and carcinoma of the prostate with a high degree of sensitivity. However, at present, differentiation between adenoma, prostatitis and carcinoma is not possible with sufficient accuracy. In these studies we were unable to establish a correlation between the signal pattern and staging and/or grading of the carcinoma. Reliable diagnosis of a prostate carcinoma still requires a biopsy. Because of the high soft tissue contrast and the possibility of selecting any orientation for the plane under investigation, however, MRI represents an improvement in the preoperative diagnosis of local spread.

Neurenteric cyst diagnosed by technetium-99m pertechnetate sequential scintigraphy

Neurenteric cysts are rare congenital anomalies which present as mediastinal tumors associated with vertebra anomalies. Two-thirds of them are lined with gastric mucosa and are potentially life threatening. An exact differential diagnosis is difficult preoperatively but is absolutely necessary because of the grave prognosis if left untreated. We present a case in which [99mTc]pertechnetate sequential scintigraphy demonstrated gastric mucosa in the cyst and helped to confirm the diagnosis. The scintigraphic findings are correlated with radiologic, sonographic, and pathologic features.

Effect of myocardial perfusion and metabolic interventions on cardiac kinetics of phenylpentadecanoic acid (IPPA) I 123

The effect of regional myocardial perfusion and flow-independent adrenergic stimulation, as well as lactate-mediated inhibition of cardiac lipolysis, on cardiac IPPA uptake and metabolism was examined in canine hearts (flow studies) and in the isolated perfused Langendorff rat heart (metabolic interventions). In both normal and ischaemic myocardium, local perfusion is a major determinant of cardiac IPPA uptake. In pacing-induced hyperaemia, the strict flow-dependence of cardiac IPPA uptake is not preserved. Adrenergic stimulation raises the rate of oxidation of both palmitic acid 14C and IPPA. This change is reflected by increased metabolite production released into the perfusate and radioactivity clearance recorded externally. Lactate in high concentrations exerts the opposite effect on cardiac free fatty acid oxidation. IPPA is stored in this condition preferentially in tissue phospholipids and triglycerides.

A comparative study of the brain uptake and early kinetics of 99mTc-dl HM-PAO and other PnAO derivatives in baboons

Derivatives of propylene-amine-oxime (PnAO) have been synthesized which form a neutral lipid-soluble complex with 96mTc and can be supplied as freeze-dried 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 99mTc-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.

[Results of fatty acid SPECT of the myocardium in coronary disease]

New developments in radiopharmacology of 123I-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 123I-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.

A Comparative Study of Brain Uptake and Early Kinetics of 99mTc-dl HM-PAO and other PnAO Derivatives in Baboons

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.

Ergebnisse der Fettsäure-SPECT des Myokards bei der koronaren Herzerkrankung

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.

Captopril mediated decrease of aortic regurgitation

The effect of captopril mediated afterload reduction on aortic regurgitation was investigated in 10 patients. Regurgitation was quantitated by means of the regurgitation fraction and the relation of regurgitant volume to end diastolic volume. These variables were derived from gated radionuclide ventriculography. After captopril treatment the blood concentration of angiotensin I rose whereas that of angiotensin II fell significantly. The conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the regurgitant volume, normalised to end diastolic volume, were significantly reduced by captopril treatment. The ejection fraction remained essentially unchanged. These findings suggest that captopril reduces aortic regurgitation by reducing afterload.

[Localization of pre-excitation in the WPW syndrome by analysis of the ventricular contraction course]

Fourier phase analysis of gated radionuclide ventriculography (RNV) was applied in 23 patient for the identification of cardiac contraction patterns in WPW syndrome (controls with normal ventricular function and sinus rhythm, n = 30). The sequence and velocity of regional ventricular wall motion was determined and correlated to the results of electrophysiological studies. In 3/23 patients the contraction pattern was not different from controls. Indicating the preexcitation in 20/23 patients the earliest ventricular contraction was localized as follows: right atrial n = 5, paraseptal right n = 2, paraseptal left n = 6 and atrial left n = 7. In 15/16 patients nuclear data corresponded with electrophysiological endocardial mapping. Phase analysis of RNV provides a reliable non-invasive method for localization of preexcitation in WPW syndrome.

Differential metabolism of deoxyribonucleosides by leukaemic T cells of immature and mature phenotype

Experimental evidence has indicated that T lymphoblasts are more sensitive to deoxynucleoside toxicity than are B lymphoblasts. These data have led to the use of purine enzyme inhibitors as selective chemotherapeutic drugs in the treatment of T cell malignancies ranging from T cell acute lymphoblastic leukaemia to cutaneous T cell lymphomas. We have compared the toxicities of 2'-deoxyadenosine, 2'-deoxyguanosine, and thymidine for T cell lines derived from patients with T cell acute lymphoblastic leukaemia with those for mature T cell lines derived from patients with cutaneous T cell leukaemia/lymphoma. We have found that both deoxynucleosides are far less toxic to the mature T cell lies than to T lymphoblasts and that the mature cells accumulate much lower amounts of dATP and dGTP when exposed to deoxyadenosine and deoxyguanosine, respectively. Similar studies performed on peripheral blood cells from patients with T cell leukaemias of mature phenotype and on peripheral blood T cells demonstrate similar low amounts of deoxynucleotide accumulation. Measurements of the activities of several purine metabolizing enzymes that participate in deoxynucleoside phosphorylation or degradation do not reveal differences which would explain the toxicity of deoxynucleosides for immature, as compared to mature, T cells. We conclude that deoxynucleoside metabolism in leukaemic T cells varies with their degree of differentiation. These observations may be relevant to the design of chemotherapeutic regimes for T cell malignancies.

Metabolism of 15 (p 123I iodophenyl-)pentadecanoic acid in heart muscle and noncardiac tissues

The uptake and turnover of omega(p 123I iodophenyl-)pentadecanoic acid (I-PPA), a radioiodinated free-fatty-acid analog, was examined in the heart, lung, liver, kidneys, spleen, and skeletal muscle of rats. At 2 min post injection, a high cardiac uptake of 4.4% dose per gram had already been achieved; this was followed by a rapid, two-component, tracer clearance. The kinetics of tissue concentrations of labeled hydrophilic catabolites indicated a rapid oxidation of I-PPA and the subsequent washout of I-PPA catabolites from heart-muscle tissue. The fractional distribution of the labeled cardiac lipids compared favorably with previously reported values for 3H-oleic- or 14C-palmitic-acid-labeled myocardial lipids. Typical patterns of I-PPA metabolism were observed in tissues depending on primary fatty-acid oxidation, lipid metabolism regulation, or I-PPA-catabolite excretion. The tissue concentrations and kinetics of I-PPA and its metabolites in the heart muscle indicated that general pathways of cardiac-lipid metabolism are traced by this new gamma-emitting isotope-labeled radiopharmaceutical.

Selective loss of a family of gene transcripts in a hereditary murine cataract

The eye lens of the Fraser mouse contains a dominantly inherited cataract with reduced amounts of seven distinct but homologous gamma crystallins encoded by a family of gamma-crystallin genes. The results of experiments with cultured lenses, cell-free RNA translation, and Northern blot hybridization indicated a specific loss of the family of gamma-crystallin messenger RNA's in the Fraser mouse lens. Southern blot hybridization of genomic DNA's from normal and Fraser mice showed no differences in gamma-crystallin coding sequences.

15(p-[123I]Iodophenyl)pentadecanoic acid as tracer of lipid metabolism: comparison with [1-14C]palmitic acid in murine tissues

Uptake and turnover of 15-(p-[123I]iodophenyl)pentadecanoic acid (I-PPA), a radioiodinated free-fatty-acid analog, was examined in heart, lung, liver, kidneys, and spleen and compared with that of [1-14C]palmitic acid (PA). High cardiac uptake of both I-PPA (4.4% dose/g) and PA (2.8% dose/g) was followed by a two-component tracer clearance. Kinetics of I-PPA were linked to those of PA in tissues with primary oxidation of free fatty acids or their preferential storage. Tissue lipids of all organs investigated were labeled concordantly by both tracers. Fractional distributions of PA and I-PPA incorporation in tissue lipids were significantly correlated. Thus general pathways of FFA tissue metabolism are traced by this radioiodinated free-fatty-acid analog. High-quality metabolic imaging of the heart is possible by means of I-PPA with conventional scintigraphic equipment or cross-sectional imaging with single photon emission computerized tomography facilities.

Cardiac metabolism of omega-(p-iodo-phenyl)-pentadecanoic acid: a gas-liquid chromatographic-mass spectrometric analysis

The omega-(p-iodo-phenyl)-pentadecanoic acid (I-PPA) has been used successfully for the investigation of the cardiac metabolic activity and for the imaging of the myocardium (Machulla, H. J., M. Marsmann, and K. Dutschka. 1980. Eur. J. Nucl. Med. 5: 171-173). In the present study, the metabolic fate of I-PPA in the perfused rat heart was investigated. After application of I-PPA to the perfused rat heart, lipids were extracted, separated by thin-layer chromatography, and transesterified. The gas-liquid chromatographic-mass spectrometric (GLC-MS) analysis yielded the following results. Heart triglycerides contained 73% of the recovered I-PPA; only small amounts of unesterified I-PPA were found in the heart. This finding is in good agreement with the radioactivity distribution determined simultaneously. Three metabolites could be detected and characterized by GLC-MS: omega-(p-iodo-phenyl)-propionic acid, omega-(p-iodo-phenyl)-propenoic acid, and p-iodo-benzoic acid. These short chain metabolites were found only in the perfusion medium demonstrating that they are not enriched but rapidly eliminated from the perfused rat heart.

Splenectomy in hematologic malignancy

Fifty patients undergoing splenectomy for complications of hematologic malignancy were reviewed to define indications and results. Primary diseases included lymphoma (n = 14), chronic lymphatic leukemia (n = 13), hairy-cell leukemia (n = 12), myeloid metaplasia (n = 6), and other similar disorders (n = 5). Indications for splenectomy in these patients included cytopenia (n = 37), diagnostic laparotomy (n = 8), "small stomach" syndrome (n = 3), and abdominal pain (n = 2). Splenectomy was performed by the midline approach in 32 patients. In 40 patients, the splenic artery was ligated prior to mobilization of the spleen. The spleens averaged 1650 g; in eight patients accessory spleens were removed. Additional surgical procedures included liver biopsy (n = 30), lymph node biopsy (n = 15), and cholecystectomy (n = 3). Intraoperative blood loss averaged 750 ml. In 14 patients, drainage of the left subphrenic space was used. Splenectomy was effective in 36 of 50 patients. In seven patients, splenectomy was ineffective in correction of cytopenia. Seven mortalities were from bleeding (n = 2), pulmonary embolus (n = 2), postoperative sepsis (n = 2), and progression of primary disease (n = 1). Additional complications included reoperation for bleeding (n = 3), septic complications including pneumonia (n = 14), wound infection (n = 4), and intra-abdominal abscess (n = 2). Splenectomy for the patients with hematologic malignancy is generally effective. Meticulous hemostasis, timely administration of intraoperative platelets, surgical asepsis, and aggressive pulmonary care are essential to reduce morbidity and mortality.

[Cerebral emission computer tomography (SPECT) with 123I-labeled amphetamines]

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.

Cardiac metabolism of 15 (p-I-123 phenyl-) pentadecanoic acid after intracoronary tracer application

Myocardial turnover of omega-(p123I-Phenyl-) pentadecanoic acid and release of its metabolites into the coronary sinus and peripheral blood has been studied in patients with coronary artery and valvular heart disease. After intracoronary tracer injection myocardial extraction fractions of 45-53% in control subjects were observed. In patients with coronary artery disease (CAD) normal to reduced values (34-61%) were established. Hydrophilic catabolites of I-PPA, probably p123I-benzoic and -hippuric acid as well as small amounts of the non-metabolized tracer were found in coronary sinus and peripheral blood. Myocardial tracer uptake and clearance patterns were clearly different in normal myocardium when compared to that obtained in patients with CAD. Thus, evaluation of myocardial I-PPA metabolism might provide a new diagnostic tool for assessment of integrity of the heart's muscular metabolic function.