Scintillation Camera Imaging Research Articles

Differentiation between renal allograft rejection and acute tubular necrosis by renal scan

The usefulness of the renal scan in diagnosing technical complications in the transplant patient is well established. However, the ability of the renal scan to differentiate between acute rejection and acute tubular necrosis has remained uncertain. We have evaluated the effectiveness of the 99mTc DTPA computer-derived time-activity curve of renal cortical perfusion, as well as data obtained from scintillation camera images, in making such diagnoses. Fifteen patients with a clinical diagnosis of either acute rejection or acute tubular necrosis, or both, were studied retrospectively. Technetium scan diagnoses did not agree with the clinical assessment in nine of the patients. Thus selection of a course of treatment should not be based on data obtained from the scan alone.

An evaluation of scintillation camera tomography

Factors for optimizing the quality of scintillation camera tomographic data for a commercial instrument were discussed. Phantom studies were conducted to compare the limits of tumour detectability for various tumour/tissue activity ratios at various depths for the tomography unit, the high resolution collimator and the rectilinear scanner. Line spread functions and modulation transfer functions for the tomography unit are compared to those for the high resolution and high sensitivity collimators. Advantages and disadvantages of scintillation camera tomography devices and rectilinear scanners were discussed. Data support the need for such a focusing capability in addition to the scintillation camera. Consideration was also given to these two focusing systems in the light of the information provided by the computerized data handling capability for standard scintillation camera imaging. A method was presented to measure quickly and accurately the calibration of a tomography unit.

A new method for radionuclide imaging of myocardial infarcts.

Lesions such as ischemia, which result in myocardial cell death, are accompanied by cellular influx of calcium ions which localize within the mitochondria in the crystalline structure hydroxy-apatite. Using 99mTc-stannous pyrophosphate, an agent which labels hydoxyapatite for bone scanning, the authors have produced scintillation camera images of experimental myocardial infarcts in dogs. Tracer localization disappears with time, suggesting application of this method to fresh infarcts.

Consideration of the Optimum Memory Capacities for Storage, and Numbers of Points for Display of Scintillation Camera Images

Consideration of the Optimum Memory Capacities for Storage, and Numbers of Points for Display of Scintillation Camera Images

99m Tc-human albumin microspheres (HAM) for measuring the rate of gastric emptying.

The radiopharmaceutical HAM (99mTc-human albumin microspheres) was used to measure gastric emptying time in a series of 29 patients (normal, 9; duodenal ulcer, 7; gastric ulcer, 7; and gastric carcinoma, 6). The mean emptying rate in each group of patients was significantly different, as was the pattern of emptying. No overlap occurred in the T-50% results for one standard deviation. The physical properties of 99mTc-HAM permit the administration of relatively large amounts of the radionuclide, creating a high photon flux which results in excellent scintillation camera images. This technique is reproducible, and tests show less than 2% absorption of the radionuclide.

Scintiangiocardiography in children: Rapid sequence visualization of the heart and great vessels after intravenous injection of radionuclide

A technique is presented for recording rapid sequential scintillation camera images of the heart and great vessels in children after the intravenous injection of radionuclide. The wide-field Anger scintillation camera, a memory oscilloscope and a 35 mm motor-driven camera are used to record images directly from the oscilloscope during the initial circulation of the radionuclide. Patients are studied in the supine position and intravenously administered technetium-99m as the pertechnetate ion in a dose of 140 μc/kg (maximal dose, 7.5 mc) is used. For each study 24 to 36 photographs are recorded with exposures of 0.25 or 0.125 sec and 1.8 or 3 exposures per sec. With this technique the central circulation is depicted by a trail of scintillations in a manner similar to that of conventional cineangiocardiography. First the normal sequential scintillation images of the heart and great vessels were clarified by studying patients without heart disease undergoing diagnostic brain scans. Then children known to have heart disease and previous cineangiocardiography were studied to compare this method with conventional contrast media visualization of the central circulation. Systemic venous abnormalities as well as alterations in intracardiac and great vessel anatomy were demonstrated with this technique. In addition, right to left shunts can be shown by early appearance of activity in the abdominal aorta. This technique is not hazardous, is associated with low radiation exposure, does not disturb circulatory hemodynamics and provides a useful diagnostic tool in the treatment of children with heart disease.

A display and storage system for radionuclide images.

The system of data processing and storage of scanning and camera images described in this report is one which we have used in our department for the past three years. This system has a number of unique advantages: (a) all original data are retained in the department; (b) scintillation camera and rectilinear scan images are viewed life-size in the same format: (c) file space is greatly reduced; (d) retrieval and analysis of data are facilitated; and (e) duplicate copies can be made quickly, easily, and cheaply. Scintillation camera oscilloscope images are recorded directly on 35 mm film, using a single-lens reflex camera (Fig. 1). Only the amount of film needed for one patient is loaded into the camera, so that the results are available before the patient leaves the department. We have selected 35 mm film that can be processed within ninety seconds. Kodak High Contrast Copy Film is used for brain scans. For dynamic studies, when higher film speed or a wider gray scale is needed, Kodak RAR 2498 is used. Rectilinear scans (14 X 17-inch), radiographs, and written reports are photographed on Type X-R 35-mm film with a semi-automatic camera distributed by Micro X-Ray Recorder, Inc., and exposed film is sent to that firm for processing. The 35-mm images from the scintillation or micro-film camera are mounted in standard aperture cards (Fig. 2), which are 80-column tabulating cards with the aperture located between columns 52 and 77. The aperture is covered with two thin layers of clear polyester film to form a pocket, which holds the film securely and protects it from scratches during sorting by hand or by an IBM card sorter. Brunsting (2) was the first to utilize aperture cards for radiograph storage, and Freedman recently reported their use in nuclear medicine (3). At first, the patient's identification number is written on the card; later, the card is key-punched with the patient's identification number as well as the type and results of the study. For viewing the 35-mm images mounted in aperture cards, the magnification factor of the viewer is the same as the reduction factor of the camera. Thus, the image is projected life-size onto a translucent screen, and measurements can be made directly on the screen without correction factors. To facilitate comparison of one view with another, all images from a patient's study are viewed simultaneously on several aperture card viewers. Cards are duplicated, using a photo aperture card copying machine (IBM Micro Copier II D). The copier duplicates the 35-mm film images onto a copy card containing an undeveloped diazo film (IBM Type DB N'S). The processor automatically exposes and develops the inserted copy card in eight seconds. Figure 3 shows an original brain scan and a diazo copy produced in the card copier.