Attenuation curves and photopeak ratios of 159 keV and 28 keV phtons emitted in the decay of 123I have been studied using a scintillation camera equipped with an extra ADC for recording the pulse height distribution of the energy signal. Cavities of various sizes containing 123I-solution were placed at different depths in a water phantom in order to vary the effective depth, i.e., the thickness of

A detailed study has been made of the method for labeling plasmin (NOVO Indstri A/S Denmark) with 99mTc in order to prepare a radioactive indicator for early scintigraphic visualization of thrombi and tumors. The best method found for preparing 99mTc-plasmic involved the reduction of 2.5 ml 99mTc-pertechnetate solution with 0.5 ml of 4 mM SnCl2, 2 M NaCl and 70 mM HCl. This mixture was then added

Image quality, resolution and sensitivity of a scintillation camera equipped with various collimators have been investigated using high purity 123I. Pulse height distributions of 123I from a thyroid phantom partly in air and partly immersed in water demonstrated the substantial septa penetration of the 440 and 529 keV gamma rays of 123I with high resolution collimators. Line spread functions were

(99m)Tc labelled macroaggregated albumin particles prepared from a commercial 'kit' have been tested in detail. With the introduction of the method of gel chromatography column scanning it became possible to make fast and simple quantitative measurements of the radiochemical purity. This was found to be the only reliable method for quantitative determination of non aggregated (99m)Tc labelled albu

A detailed study has been made of the method for labeling streptokinase with 99Tc(m) in order to get a radioactive indicator for rapid scintigraphic visualization of thrombi and emboli. The best method found for preparing 99Tc(m) streptokinase was by reducing 99Tc(m) pertechnetate with 2 μmole SnCl2 at pH 0.7 and then adding 50,000 to 75,000 IU of streptokinase at a final pH of about 2. After 1 hr

The gel chromatography column scanning (GCS) method has been studied, special attention being paid to its suitability for the analysis of 99mTc-labelled compounds and radio-pharmaceuticals. The sample to be analyzed was applied at the top of a column filled with Sephadex G gel. Elution was carried out with 0.9% sodium chloride solution with such a volume that all the radioactivity was retained in

Lichens of the genus Cladonia, mainly C. alpestris, collected during 1882-1972 were analyzed for stable lead and 210Pb. The specific activity of 210Pb (210Pb/Pb ratio) indicates a constant value of about 2 mCi/kg up to 1940, and then decreased to 0.6 mCi/kg during 1950-1960. As the average annual 210Pb deposition is relatively constant, the decrease in the 210Pb/Pb ratio after 1940 indicates an in

The transport of fallout-90Sr has been investigated in the food-chain: Lichen-reindeer-man during 1961-1969. The maximum levels which occurred in lichen during 1963-1965 were about 13 nCi/kg dry wt. The90Sr-level in the lichen-carpet decreased to about 5 nCi/kg dry wt. in 1967-1969. The effective half-time of 90Sr in the lichen-carpet was estimated to be 2.5 ± 0.8 a. The vertical distribution of90