Cerebral dynamics of N-isopropyl-(123I)p-iodoamphetamine.

Temporal changes in the distribution of N-isopropyl-(123I)p-iodoamphetamine (IMP) within the brain are measured with serial tomographic imaging. In the cerebellum there is a decrease in activity of 42% from the early [15-45 min postinjection (p.i.)] to the late (210-240 min p.i.) scan, while in the cortex the decrease is 18%, and in the basal ganglia there is no decrease within this time. In brain tumors there was no IMP uptake in the early as well as in the late scans, regardless of tumor type, perfusion rate, or blood-brain barrier dysfunction. In 11 of 43 patients with a cerebral infarction a real increase of 123I activity (mean +21%) was seen in the late images. This "filling in" phenomena might be useful in selecting patients for bypass surgery. In these patients the diaschisis cerebelli, seen in the early scans, disappeared in the late images. The regional distribution of IMP changes with time; spatial ratios might be blurred by temporal changes. High-flow areas such as visio-auditory centers can be delineated clearly after stimulation in fast early scans; in these areas the pharmacokinetics of 123I are different from other cortex regions. To get the full information from the IMP brain uptake, both spatial and temporal variation must be measured.

Splenic regeneration and blood flow after ligation of the splenic artery or partial splenectomy.

In normal, young miniature piglets, either the major arteries and the veins were ligated or three quarters of the spleen was resected using three different techniques. These techniques served as an animal model for splenic salvage in human subjects. After arterial ligation, no signs of infarction could be seen 1 and 4 weeks later, and after 6 months, normal sized spleens with enlarged vessels in the gastrolienal ligaments were found. When the splenic remnant was left at the main vessels, no obvious growth could be demonstrated after 6 months. The splenic tissue left at the smaller vessels, however, increased in size. Measurements of splenic blood flow in unanesthetized piglets 6 months after operation resulted in greater differences in perfusion per gram among the experimental groups. Not only splenic mass, but also blood flow to the whole splenic tissue seems to be an important factor in the protective function of the spleen.

[A comparison of osteotropic radiopharmaceuticals. II. Plasma clearance of 18F and 99mTc-EHDP (author's transl)]. / Vergleichende Untersuchungen mit osteotropen Radiopharmaka. II. Plasmaclearance von 18F und 99mTc-EHDP

Renal and extra-renal clearance of 18F and 99mTc-EHDP were compared in the same individuals. The 18F space is twice that of 99mTc-EHDP, as is its renal clearance. 99mTc undergoes glomerular filtration, 18F is excreted by glomerular filtration and tubular secretion. Extraction rate was determined indirectly by a comparison with extra-renal clearance, and for patients without bone disease it was four times as high for 18F as it was for 99mTc-EHDP. In patients with secondary hyperparathyroidism extra-renal clearance is greatly increased. This is explained by an increased extraction rate, which may be different for the two substances.

[Comparative investigations concerning osteotropic radiopharmaceuticals. III. Scanning with 18F and 99mTc-malignant diseases (author's transl)]. / Vergleichende Untersuchungen mit osteotropen Radiopharmaka. III. Szintigraphie mit 18F und 99mTc-EHDP bei malignen und nichtmalignen Erkrankungen

Total body scans under identical conditions and using 18F and 99mTc-EHDP were carried out in patients with known, or subsequently proven, metastases. There was no statistical evidence for any difference in the number of scintigraphically demonstrable lesions. Patients with internal prostheses who developed infections of the prosthesis show no significant difference in the uptake of either nucleid. Soft tissue lesions showed a significantly higher uptake of 99mTc-EHDP than of 18F. 18F can be replaced for nearly all problems by 99mTc-EHDP without loss of diagnostic information.

[Comparative investigations of osteotropic radiopharmaceuticals. V. Demonstration of abnormal uptake with various scanners (author's transl)]. / Vergleichende Untersuchungen mit osteotropen Radiopharmaka. V. Nachweis pathologischer Anreicherungen mit unterschiedlichen Szintigraphiegeräten.

Experiments with phantoms have shown that there is a higher probability of showing areas of increased uptake when using a camera than with a scanner. In 49 patients with suspected bone metastases, scans were performed during their pre-operative work-up, under identical conditions, using a whole body scintigraphic scanner with a 5-inch double head and a scintillation camera with total body facility. The scintillation camera showed a significantly higher sensitivity to bone metastases, but there was no difference in the pick-up rate of distant metastases. Despite the possibly more frequent use of the camera, its cost is no higher than that of the scanner. Both on diagnostic and economic grounds, we consider the scintillation camera, with a total body facility, to be the instrument of choice for total skeleton scintigraphy.

[Salivary gland scintigraphy after radio-iodine therapy. Functional scintigraphy of the salivary gland after high dose radio-iodine therapy (author's transl)]. / Funktionsszintigraphie der Speicheldrüsen nach hochdosierter Radiojodtherapie. Laufender Titel: Speicheldrüsenszintigraphie nach Radiojodtherapie

Following high dose radio-iodine therapy, some radiation damage to the salivary glands is to be expected since iodine is taken up by these glands. The great individual variation in the uptake makes it impossible to predict the severity of the damage. T max and maximal excretion capacity after stimulation were therefore estimated by a camera functional scintigram with digital read out in patients following radioiodine therapy (0.1-3.2 Ci); the excretion index was used as an indirect measure of salivary flow. After a dose up to 0.3 Ci there is a change of T max and maximal excretion capacity in 30% of patients; after a dose of 0.5 to 1 Ci it is found in 60 and 80% and after very high doses of 1.1 to 3.2 Ci an abnormal Tmax was found in two-thirds of all patients and reduced or absent excretion capacity in all nine patients in this group. The excretion index also depended significantly on the cumulative dose. All patients who had received very high doses showed marked hyposialia or asialia. The early results of interim examinations suggest, similar to radio-iodine induced hypothyroidism, a cumulative risk of reduced function. In view of the long survival period of patients with differentiated thyroid carcinomas attention should be drawn to this side effect.

[Comparative investigations of osteotropic radionucleides. IV. The dynamics of uptake in normal and abnormal bone (author's transl)]. / Vergleichende Untersuchungen mit osteotropen Radionukliden; IV. Dynamik der Anreicherung im normalen und pathologisch veränderten Knochen

The dynamics of uptake of osteotropic radionucleides in normal and abnormal bone were studied by means of sequential and functional scans. Various phosphate and phosphonate complexes were compared in vivo and in vitro. Only phosphonates were considered as suitable for bone scanning. In normal bones in beagles, radioactivity after HEDP fell to 65% after two hours, but was 105% with 18F. In relation to healing fractures, the curves differ quantitatively and qualitatively. In this situation, functional curves derived from dynamic scans provide a better parallel with histological findings than does static scintigraphy with an uptake quotient. Sequential and functional scanning are able to document the therapeutic effect of irradiation of bone metastases.

[Scintigraphic image of bile reflux following gastric and intestinal surgery]. / Szintigraphische Darstellung des Gallenrefluxes nach Magen- und Darmoperationen.

Bile reflux may occur after a variety of reconstructive procedures in the gastro-intestinal tract and biliary system. The present paper deals with reflux into the duodenum, jejunum, stomach, oesophagus and into blind loops. The demonstration of reflux by 99mTc labelled IDA acid derivatives, and a possible quantitative approach, are discussed. The advantages of an isotope method are: 1. Direct demonstration of bile reflux without any intervention in the physiological process and with little trouble to the patient, 2. The ability to use the method for various reconstructive procedures and 3. The additional information obtained which may help in the differential diagnosis of blind loops, biliary obstructions, cholecystitis or liver metastases if there has been a gastrectomy for a malignant tumour. In combination with a second administration of a radio-isotope tracer, one may be able to demonstrate abnormalities in the motility of the stomach or gut, or pyloric stenosis or gastro-oesophageal reflux.

[Comparative investigations of osteotropic isotopes. i animal experiments on the uptake of 18f, 85sr and 99mtc-ehdp (author's transl)]. / Vergleichende Untersuchungen mit osteotropen Radiopharmaka. I. Tierexperimentelle Untersuchungen zur Anreicherung von 18F, 85Sr und 99mTc-EHDP

In normal rabbit bones, as well as in callus, there is significantly more uptake of 18F than of 85Sr or 99mTc-EHDP. Extraosseous abscesses show significantly higher uptake of 99mTc than of 18F or 85Sr. In the presence of hyeraemia, there is no significant difference in the uptake of the various osteotropic radio-nucleides.

[Dynamic reflux scintimetry for quantifying gastroesophageal reflux in patients with prolonged esophageal transit]. / Die dynamische Refluxszintimetrie zur Quantifizierung des gastroösophagealen Refluxes bei Patienten mit verlängertem ösophagealen Transit.

A combination of a radionuclide transit test and a dynamic gastroesophageal scan was evaluated in normal volunteers, in patients with achalasia treated by pneumatic dilatation (n = 34) or Heller myotomy (n = 21). Interpretation of 31 of 57 examinations done with usual scintiscan was not possible because of too high esophageal tracer retention. Only one case could not be interpreted with the modified technique. Gastroesophageal reflux was detected and quantified in this manner in 8 patients, 6 more than with the usual scintiscan. 7 of these 8 patients have had Heller procedure, 1 patient even combined with fundoplasty.

[Demonstration of postgastrectomy bile reflux by hepatobiliary sequential scintigraphy]. / Nachweis von Gallereflux nach Gastrektomie mit der hepatobiliären Sequenzszintigraphie (HBSS).

After gastrectomy and jejunal interposition by the Longmire technique, symptoms due to alkaline reflux oesophagitis may occur, which are caused by duodeno-jejunal and jejuno-oesophageal bile reflux. Twenty-seven patients who had gastrectomies performed for malignant tumours one to three years previously were examined by hepatobiliary sequential scintigraphy in order to see whether this is able to demonstrate bile reflux. In addition to endoscopies, biopsies and radiological examinations, 45 sequential scintigrams were carried out. Agreement of results during routine use was investigated for five observers. There were considerable variations in results amongst different observers. Nevertheless, in four out of the five observers, there was a significant correlation with the clinical findings (p less than 0.05). Only by using functional scintigraphy with digital data recording is it possible to demonstrate or exclude bile reflux with any degree of certainty. Eight out of twelve patients with marked symptoms, and four out of 28 without symptoms showed reflux into the interposed segment (correlation 0.7, p greater than 0.05). Patients with symptoms showed a high incidence of oesophagitis by the above-mentioned methods (correlation (0.52, p greater than 0.05). Correlation between the results of barium meals and clinical findings was considerably less (0.25) and was not significant. Sequential scintigraphy is therefore better for clarifying reflux symptoms than radiological examination or endoscopy and biopsy.

[11C-methionine PET, IMP-SPECT, CT and MRI in brain tumors]. / 11C-Methionin-PET, IMP-SPECT, CT und MRI bei Hirntumoren.

11C-labelled L-methionine uptake was measured in 7 patients with brain tumours prior to surgery, and in 2 patients with infarction, using PET. The strongest uptake occurred in tumours with a high grade of malignancy (astrocytoma IV: Tumour/Non-Tumour T/NT = 2.6) while low-grade tumours accumulated less activity (astrocytoma II: T/NT = 1.4). Conventional 99mTc DTPA scans revealed a damage of blood brain barrier (BBB) in 4 patients (2 infarctions) with no or only slight 11C-methionine accumulation, while one patient with negative 99mTc-scan and negative CT accumulated methionine in the tumour region (astrocytoma II). PET, MRI, and CT are complementary with regard to extent of tumour tissue, necrotic areas and oedema. None of the brain tumours or infarcted regions took up IMP (123I amphetamine). The investigated regions showed definite uptake defects ranging from 10-50% if compared with the contralateral side. In view of the chemical pathway of methionine it is concluded that the uptake reflects metabolic activity in brain tumour tissue rather than a diffuse uptake due to BBB damage.

[Quantitative measurements of regional extra-vascular lung water in dogs using positron emission tomography]. / Quantitative Messung des regionalen extravaskulären Lungenwassers bei Hunden mit der Positronen-Emissionstomographie.

A new method for quantifying regional variations in extravascular lung water (rELW) has been developed. The positron source 15O (T1/2 = 2.0 min.) was provided as H215O 'on line' by constant intravenous injection. Tomographic images (PET) of the water distribution were obtained during equilibrium. The distribution of blood volume was obtained by marking erythrocytes (carboxyhaemoglobin) using a bolus inhalation [C-11)-CO; T1/2 = 20.4 min). Absorption is calculated from transmission tomography. The rELW is defined as: total lung water minus intravascular space. The method was carried out in five intubated and anaesthetised dogs before and after induction of pulmonary oedema with oleic acid (0.06 ml./kg.). Mean ELW (PET) rose from 0.13 +/- 0.02 g./cm.3 to 0.24 +/- 0.04 g./cm.3. There was good correlation with a simultaneously performed thermo-dye method (7.1 +/- 1.3 ml./kg. KG to 13.3 +/- 1.9 ml./kg. KG; r = 0.94). Gravimetric estimations resulted in 13.7 +/- 2.6 ml./kg. KG. The development and distribution of the pulmonary oedema was non-homogeneous and varied regionally.

[Methodological observations on double radionuclide technics in joint scintigraphy]. / Methodische Anmerkungen zur Doppelradionuklidtechnik bei der Gelenkszintigraphie.

Double-radionuclide scintigraphy for the differentiation between inflammatory and degenerative diseases of the joint ought to be performed with a radiopharmaceutical that remains within the intravascular space as an indicator of blood flow, and an osteotropic radiopharmaceutical. The former ought not to leave the intravascular space even in inflammatory disease. This condition is, however, not met by 113mIn-labelled transferrin as shown by measurements of plasma volumes as well as of its local kinetics. On the other hand, the biological behavior of 99mTc-labelled red cells does not, up to 30 min p.i., differ from that of 51Cr-labelled red cells so that they may be used as an intravascular tracer even in inflammatory disease. In that case, the osteotropic radiopharmaceutical to be employed should be 113mIn-EDTMP.

[Is a dosage calculation for radio-iodine therapy possible?]. / Ist eine Dosisberechnung für die Radiojodtherapie möglich

When trying a single-dose 131I therapy in thyrotoxic patients a dose calculation must be done to avoid an overtreatment raising the risk of posttherapeutic hypothyroidism. The calculation is based on the diagnostic 131I uptake, the thyroid weight, and the effective intrathyroidal halflife of the diagnostic 131I dose. In 46 thyrotoxic patients the radiation dose was calculated with 7000 R for small and 10 000 R for large (50--100 g) glands using the formula of Billion. Iodine-131 was given in a single dose. Therapeutic dose uptake was measured every day and the effective T 1/2 calculated using a least squares computer fitting to an monoexponential decrease. The radiation dose was then recalculated using the same formula. Small glands received 10 700 +/- 4300 R (SEM 1008 R) instead of calculated 7000 R; large glands 8600 +/- 4100 R (SEM 860) instead of 10 000 R. There was a significant correlation: the smaller the gland the higher the radiation dose. The smallest glands received 12 000 to 16 000 R. There might be such a great difference between calculated and received radiation dose than an individual prediction will be impossible. In our patients a careful calculation for the single-dose treatment was done; nevertheless in some cases an overtreatment of more than 100% was seen. A comparison of responding or overresponding to therapy with the radiation dose is only reliable using individual dosimetry with the therapeutic 131I dose.

[Determination of liver circulation with radionuclides. I. Modification of 99mTc-MMS accumulation in the liver using drugs]. / Zur Bestimmung der Leberdurchblutung mit Radionukliden. I. Beeinflussung der 99mTc-MMS-Anreicherung in der Leber durch Pharmaka.

The rate constant of liver uptake of 99mTc-labelled millimicrospheres is taken to be a measure of nutritive RES blood supply. Animal experiments were used to determine whether this constant--similar to that of other colloids--is affected by drugs such as heparin or corticosteroids which alter RES function. In rabbits, the scatter of k between individuals is quite large, with a standard deviation of 27%, whereas the scatter within an individual appears to be acceptable (8%). Heparin does not change the value of k significantly, whereas prednisolone in a dose of 40 mg/kg BW--a dose that is normal in bolus therapy--reduces k significantly by 21%. If k is determined during such therapy, its reduction may be due to the pharmacological effect and must not be interpreted as a rejection phenomenon.

[Quantitative sacroiliac joint scintigraphy? (author's transl)]. / Quantitative Knochenszintigraphie des Ileosacralgelenkes?

Methodological aspects and clinical value of digital sacroiliac joint scintigraphy area are described. Preinformation of the observer affects the value of the uptake ratios significantly. A data processing is presented which reduces this effect. Nevertheless there is insufficient discrimination between normal persons and patients with acute inflammation. Routine bone scanning can therefore not be used to exclude "inflammatory changes".

[Ferrokinetics in 1-dimensional whole-body profiles in hematologic diseases]. / Ferrokinetik in eindimensionalen Körperlängsprofilen bei hämatologischen Erkrankungen.

Quantitative whole-body linear profile scans of 59Fe, obtained by a whole-body counter, conventional ferrokinetics and hematological parameters are investigated in patients (n = 208) with various hematological-oncological diseases. Linear whole-body profile scans in controls, obtained 24 h after i.v. injection of 59Fe-transferrin, give quantitative information about sites of the erythropoietic system. Early profile scans (1 h p.i.) in patients with anemia show a typical 'iron-suction' corresponding to the fast outflow of 59Fe from the blood compartment. We found no typical change of iron distribution in Hodgkin and Non-Hodgkin lymphomas, even in patients with anemia or hemolysis there was no evidence of expansion of erythropoiesis to distal marrow sites. Our investigation does not contribute to staging of patients with Hodgkin's disease. Osteomyelofibrosis is characterized by a centrifugally expanded erythropoiesis. The value of increased iron uptake 24 h p.i. in leg regions for differential diagnosis of hemolytic anemia, chronic myelocytic leukemia, and pancytopenia where a similar pattern of iron distribution is observed will be discussed. Quantitative iron kinetics with one dimensional 59Fe profile scans give additional information in patients with displaced erythropoietic system.

[Nuclear medicine diagnosis of pulmonary capillary protein leakage]. / Nuklearmedizinische Diagnostik des "Pulmonary Capillary Protein Leakage".

Pulmonary extravascular albumin extravasation in patients with adult respiratory distress syndrome can be quantified with radionuclide techniques. While imaging procedures with a computerized gamma camera will allow reproducible ROIs, this will be the main limitation in nonimaging measurements with small scintillation probes. Repeated positioning by one operator results in a mean spatial variation of position of about 2 cm and a variation in count rate of 25%. For the estimation of PCPL the small probes must be positioned under scintigraphic control. Under these conditions the results of both techniques are identical. The upper limit of normal was estimated to be 1 x E-5/sec. The standard deviation of abnormal measurements was about 10%. The pulmonary capillary protein leakage can be quantified by radionuclide techniques with good accuracy, using the combination of imaging and nonimaging techniques.

[The arterial contribution to total liver perfusion (author's transl)]. / Der arterielle Anteil an der Lebergasamptperfusion.

Dynamic hepatic scintiangiography is a method of estimating some aspects of liver hemodynamics. Especially in cirrhotics and in liver-grafted patients this method may be clinically useful. We studied some methodological aspects of the differentiation between the arterial and the portal positions of the liver time activity curve. In 16 patients with otherwise proven pure arterial perfusion of the liver there wee three different forms of the curve: in 8 cases the first peak was followed by a second upslope. In 5 cases there was a plateau after the peak, and in 3 cases the peak was followed by a downslope of the curve. No general description of all curves could be found. Therefore all methods using plateau techniques for subtracting the arterial from the portal portion of the curve seem to be doubtful. In these and in other patients five different techniques were compared: the arterial part was much underestimated by the method of George (76 +/- 9%), slightly underestimated by the method of Biersack (91 +/- 8%), and much overestimated by the method of Boyd (123 +/- 11%). The methods of Fajman and our modification estimated always 100% in the patients with pur arterial perfusion. Comparing a set of independent evaluations the mean deviation wa 11% in normals and 23% in cirrhotics of arterial part. Only rough changes of the arterial to portal ratio of hepatic perfusion can be evaluated by dynamic hepatic scintiangiography.