P. Richards

Technetium-99m DTPA: a new radiopharmaceutical for brain and kidney scanning.

Abstract Technetium 99m was combined with the chelating agent DTPA in order to obtain a scanning agent with the physical properties of the radionuclide technetium 99m and the desirable biological properties of chelating agents. The method for the preparation of the chelate is described. No toxic effects are expected. About 90 per cent of the compound is eliminated by the kidneys in twenty-four hours. The absorbed radiation dose is 0.042 rad/mCi by the kidneys and 0.555 rad/mCi by the bladder. In clinical studies the chelate is useful for scanning of brain and kidneys and for vascular dynamic studies.

Lymph Node Scanning with 99mTc-Sulfur Colloid

Technetium 99m was originally suggested as a possible medical tracer because of its ideal physical properties (1). Subsequently several technetium-99m-labeled radiopharmaceuticals were developed and are now widely used. One of them, 99mTc-sulfur colloid, has been employed for several years for scanning of the liver, spleen, and bone marrow (2). Studies in animals have shown that this radiocolloid preparation can also be used for lymph node scanning. In our experience with patients we have found that lymph node scanning with gelatin-stabilized 99mTc-sulfur colloid prepared by the H2S method is a simple, safe procedure and that scans of good quality can be obtained. Materials and Methods 99mTc-sulfur colloid was prepared by a procedure slightly modified from the one previously described (2). This method produces a colloid with particles substantially smaller than those produced by other commonly used methods. The particle size has not been determined precisely so far, but studies of the biological behavior ...

Evaluation of 99mTc-DTPA Prepared by Three Different Methods

Abstract Comparison of the biological behavior of three compounds containing DTPA and technetium 99m shows that only two of these compounds are true chelates. The third compound, produced with a kit (Renotec), is similar in behavior to that of the renal scanning agent 99mTc-Fe-ascorbic acid.

Vascular Imaging with 99mTc-Red Blood Cells1

99mTc can be firmly labeled to erythrocytes and used for vascular pool imaging in this form. Since large amounts of activity can be administered, some of the peripheral vessels can be visualized with good resolution. The technique may be useful for investigation of arteriosclerotic vascular disease.

Vascular imaging with 99m Tc-red blood cells.

99mTc can be firmly labeled to erythrocytes and used for vascular pool imaging in this form. Since large amounts of activity can be administered, some of the peripheral vessels can be visualized with good resolution. The technique may be useful for investigation of arteriosclerotic vascular disease.

High-Specific-Activity 99mTc Human Serum Albumin

The authors describe a method of preparing high-specific-activity 99mTc HSA for use in cisternography and preparation of macroaggregates by adding 25 mg HSA, pertechnetate, and buffer to stannous chloride solution. The 99mTc HSA yield is >95%, as determined by gel chromatography.

High-specific-activity 99m Tc Human serum albumin.

The authors describe a method of preparing high-specific-activity 99mTc HSA for use in cisternography and preparation of macroaggregates by adding 25 mg HSA, pertechnetate, and buffer to stannous chloride solution. The 99mTc HSA yield is >95%, as determined by gel chromatography.

Renal Uptake of 99mTc-Iron-Ascorbic Acid Complex in Man1

A complex of technetium 99m with iron and ascorbic acid was used to image the kidneys. Eighteen patients were studied to determine renal excretion, plasma levels, whole-body retention, and renal localization. Two different methods of preparation of the material were utilized. The results indicate little difference between the two compounds. Total-body retention at twenty-four hours, measured by whole-body counting and urinary excretion, was about 25–31%, of which 4–10% was in the kidneys.

A Comparison of Conventional and Blended Display Technics in Scintiscanning

Data blending was introduced by Christie and MacIntyre (1, 2) to eliminate statistical fluctuations in the presentation of data obtained in scintillation scanning. Beck (3, 4) pointed out the improvement in perception obtained by eliminating or filtering out the high-frequency “noise” caused by statistical variation. For this he used a recording light spot which simulated the response of the detector collimator at its focal point. On the other hand, the method has been criticized for duplicating the poorest feature of the system, the collimator, and for a resultant loss in resolution (5, 6). We have employed a data-blending technic in our laboratory for the past two years (7). It has appeared to be quite satisfactory and is preferred over conventional methods of recording. We felt it necessary, however, to investigate further the capabilities of the method and compare it with a conventional technic. Methods Two scanners were used in these studies. A 3 × 2-in. crystal detector, Picker Magnascanner, was mod...