Fazle Hosain

Binding of trace amounts of ionic indium-113m to plasma transferrin

When indium-113m was injected intravenously in ionic form for blood pool scanning, it was bound to plasma transferrin. In vitro studies utilizing starch gel electrophoresis and immunoelectrophoresis showed that trace amounts of indium were bound almost entirely to the transferrin; iron-59 labeled plasma was used for comparison. Starch gel electrophoresis and gel filtration were carried out with plasma samples containing increasing amounts of indium. It appeared that approximately 4 μg of indium per ml of normal human plasma saturated the transferrin and the excess indium above this level was bound mainly to α2-globulins.

Indium-113m diethylenetriaminepentaacetic acid (DTPA): a new radiopharmaceutical for study of the kidneys.

The short-lived radionuclide, indium 113m, obtained as a daughter product of tin 113, has been used in various chemical forms for different types of organ scanning (1–3). 113mIn emits 392-keV gamma rays and decays with a physical half-life of 1.7 hours. Diethylenetriaminepentaacetic acid (DTPA) combined with 113mIn has been found useful for brain scanning (2). Because of favorable biological and physical characteristics, multimillicurie amounts may be safely administered; these result in relatively high photon fluxes particularly suitable for external detection. We have now demonstrated that indium-DTPA is excreted primarily by glomerular filtration and believe this agent to be useful for renal scanning, renography, and the rapid estimation of glomerular filtration rate. Materials and Methods 113mIn-DTPA complex was prepared as suggested by Stern et al. (2). Twenty millicuries of 113mIn was eluted with 0.05 N HCl (about 8 ml initially) from a tin-113 generator. Two hundred μg of carrier iron (0.2 ml FeCl3...

Measurement of glomerular filtration rate using chelated ytterbium-169

Abstract Ytterbium-169 chelated with diethylenetriaminepentaacetic acid ( 169 Yb-DTPA) was developed and evaluated for possible use as a glomerular substance. The radionuclide has a high photon yield with complex gamma ray spectrum. It has a physical half-life of 32 days, but less than 1 percent of intravenously injected chelated complex is retained in the body, which limits the radiation exposure. Gel fitration studies showed that 169 Yb-DTPA complex did not bind to plasma proteins and was excreted unchanged in the urine. The clearance rate of the complex was found to be independent of the plasma concentrations of Yb-DTPA. The renal clearance of 169 Yb-DTPA was compared simultaneously with that of 14 C-inulin in dogs, normal human subjects and patients with renal disease. Nearly identical results were obtained with both the agents over a wide range of glomerular filteration rate. The radiation doses due to different glomerular agents containing 131 I, 125 I, 57 Co, 99 m Tc, 51 Cr, 113 m In, 140 La and 169 Yb were calculated for normal and impaired renal conditions, 169 Yb-DTPA was found to deliver comparatively low radiation doses. It was believed to be a safe, inexpensive and effective new agent for the measurement of glomerular filtration rate.

Ytterbium-169 Diethylenetriaminepentaacetic Acid Complex: A New Radiopharmaceutical for Brain Scanning

RADIOACTIVE mercury-labeled chlormerodrin is the most widely used brain scanning agent today, but technetium-99m pertechnetate is continually gaining popularity and may soon replace it. Short-lived indium-113m chelate has also been employed successfully for brain (11) and kidney (9) scanning. These short-lived isotopes have greatly improved radionuclide imaging with decreased irradiation of the patient. We have developed a new radiopharmaceutical which depends on a short biological half-life to limit the radiation dose. This compound is prepared by chelating trivalent ytterbium 169, an isotope of one of the rare earth elements, with diethylenetriaminepentaacetic acid (DTPA). Ytterbium has several stable isotopes. The stable 168Yb has a natural abundance of only 0.135 per cent, but a very high thermal neutron capture cross-section (11,000 barns). It is available in enriched form, facilitating the production of 169Yb of high specific activity (greater than 100 mCi/mg). The product contains less than 1 per c...

A New Radiopharmaceutical for Cisternogrgphy: Chelated Ytterbium 16911

169Yb-DTPA, which has been employed for brain and renal studies, has now been used safely for cisternography in over 30 patients referred for investigation of hydrocephalus or rhinorrhea. It is physiologically stable and diffuses into the blood from the cerebrospinal fluid. Its biological half-life in the CSF compartment is about ten hours, long enough for cisternography but short enough to keep the radiation dose low, even with millicurie doses. The radionuc1ides long physical half-life, together with the stability of its complex, permits strict quality control.

Measurement of plasma volume using 99Tcm, and 113Inm labelled proteins

The short-lived 132I-labelled serum albumin (HSA) has previously been used for the repeated estimations of blood volume with reduced dose of radiation. The possibilities of using 99Tcm-HSA and 113Inm-chloride (the shortlived blood-pool scanning agents) for similar measurements have been explored. Simultaneous measurements of plasma volume were carried out in human subjects using 99Tcm-HSA or 113Inm-chloride with 131I-HSA. The values obtained with the new agents were comparatively higher (about 5 per cent) than results with 131I-HSA. Studies in dogs showed that a direct slow injection of 113InmCl3 in acidic saline could be used for the measurement of plasma volume, though pre-labelling of plasma transferrin by simple mixing improved the accuracy. The method was applied in repeated estimations of blood volume within a few hours in normal women and to determine changes in blood volume after delivery in pregnant women. The relative values of whole body radiation doses per estimation of plasma volume were calc...

Visualization of renal structure and function with chelated radionuclides.

PHYSIOLOGICALLY stable metal chelates are usually excreted by glomerular filtration. We have previously reported that short-lived indium 113m chelated with diethylenetriaminepentaacetic acid is potentially useful for studies of kidney, that is, for the measurement of glomerular filtration rate, renogram studies, and kidney scans (8). Subsequently, we developed ytterbium-169-DTPA complex (4) which has a longer half-life and can also be used for renal studies (5). Preliminary studies on the use of these chelates to visualize both renal structure and function with the help of a scintillation camera were reported at the 1968 meeting of the Society of Nuclear Medicine (9). Recently, Hisada et al. (3) have also used 113,mIn-DTPA complex for similar studies. Other useful chelates include the long-lived 51Cr-DTPA complex (2) and the short-lived 68Ga-EDTA complex (7). Relative whole-body radiation doses were considered for the use of the chelates labeled with 68Ga, 113mIn, 51Cr, and 169Yb in normal subjects as wel...

Breast milk content of 131I in a hypothyroid patient.

An oral dose of 185 MBq of 131I (sodium iodide) was administered to a lactating mother for whole body scanning. Breast milk was collected at several points in time, and assayed for radioactivity. The radioiodine concentration in the milk was found to be 4 MBq/dL at 6 h (about 2% of the dose). The radioactivity in breast milk decreased with a biological half-life of about 15 h in this hypothyroid patient. Following ingestion of radioiodide (such as [131I]sodium iodide), the appearance of radiolabel in breast secretion has been well documented. However, data do not appear in the literature on this process in the grossly hypothyroid state. We, therefore, are reporting our experience with such a situation.

Determination of LD50 of barium chloride and allied agents.

The present study reports in detail the LD50 determination in white mice of ICR strain from iv administration of barium in the form of chloride. The LD50 value was found to be 19.2 mg Ba2+/kg. The results for nitrate and acetate were close to chloride, but in Swiss-Webster strains these values were lower by a factor of almost 2. Further, LD50 values for Mg, Ca and Sr (using chlorides in ICR-mice) were 14.4, 42.4 and 147.6 mg/kg, respectively.

Technetium-99m labelled imidodiphosphate: an improved bone-scanning radiopharmaceutical

Technetium-99m labelled imidodiphosphate was prepared in the presence of stannous ions. It was evaluated as a bone-scanning agent in animals and patients. Comparative tissue distribution studies in mice showed a relatively higher uptake of radioactivity in bone when 99Tcm -labelled pyrophosphate and diphosphonate. Accumulation of radioactivity in soft tissues, especially kidneys, was less with this radiopharmaceutical. Results in patients were most satisfactory in delineating skeletal bone and identifying bone lesions with relatively small tracer doses of the radiopharmaceutical.