Gamma-ray Scintillation Camera Research Articles

PSPMT and photodiode designs of a small scintillation camera for imaging malignant breast tumors

The authors are investigating the concept of utilizing a small gamma ray scintillation camera to help identify and localize malignant breast tumors after a in a mammogram. Excellent sensitivity and specificity for malignant breast tumors has been achieved using conventional nuclear medicine scintillation cameras with certain /sup 99m/Tc-labeled radiopharmaceuticals. However, because of the large size, low image resolution and high cost of these devices, they are not ideal for use in breast imaging in a mammography suite. A dedicated miniaturized camera would allow imaging at angles that are physically impossible with the standard camera. These lateral views would not include the background activity from the heart and liver. In addition, with a potentially higher intrinsic resolution, shorter collimator and if breast compression is applied, a small camera could significantly improve the sensitivity and signal to noise ratio for the scintillation imaging method. The authors are exploring 2 different photodetector technologies for a small prototype camera development. The first uses a position sensitive photomultiplier (PSPMT) as the photodetector, the second, an array of silicon PIN photodiodes (PD). In this report, the authors present imaging results obtained with a NaI(Tl)-PSPMT design, and the design features, expected performance and relevant energy and position measurements obtained for a test CsI(TI)-PD device.

Radioisotopic study of arteriovenous anomalies.

Tc99m sequential scintigraphy of the brain detected all of 17 cases of cerebral arteriovenous malformations and racemose angiomas of the scalp. The focus was best shown in the earliest phase of studies and particularly in the first stage films. The detection rate decreased with the passage of time after administration of Tc99m.The data-store/playback accessory further permits the analysis of circulatory dynamics of the brain. Transit time and local cerebral blood flow are determined, in the multiple regions of interest, for various size and location. Size of the arteriovenous shunt is estimated by I131 macroaggregated albumin brain-lung scintigraphy.Although the individual techniques described are not new, combined use of these 3 studies is easy to perform with the gamma-ray scintillation camera and data processing equipment. These physiologic data seem to be of value in the neuroradiologic examination of cerebral arteriovenous fistulas.

Rapid diagnosis of pericardial effusion utilizing the scintillation camera

A new method for the rapid diagnosis of pericardial effusion employing the gamma ray scintillation camera and an intravenous bolus injection of technetium sulfide 88 Tc is presented. Since a chest roentgenogram is not required and scanning times are significantly reduced, this method appears to be superior to previously reported radioisotopic techniques.

Dynamic radioisotope study with a gamma camera-VTR system-RI angiography and CBF study in neurosurgical practice.

Recent advances in refinements of instrumentation, in improvement of scanning technique and data processing, and in development of appropriate radioisotope preparations with a short half-life, have made the radioisotoiic studies of the brain a reliable diagnostic and investigative took whicl is indispensable in the field of neurosurgery. The use of a gamma-ray scintillation camera and a short-lived radioisotope permits the dynamic study of an isotope bolus as it traverses the normal and pathologic focus in the brain. Vascular phases of the scintigrams are stored and replayed by the use of a video-tape system. Following this, the time-lapse scintiphotography and the use of a memory system make possible the digital assessment of the time course of regional radioactivity in multiple areas in the brain. More recently, a gamma camera have been used for the purpose of blood flow and perfusion analysis of the brain, and these have often proved to be a useful adjunctive technique in the clinical as well as research studies in the selected cases. The purpose of this paper is to summarize the recent experiences of radioisotopic studies with a gamma camera and a video-tape system, and to evaluate their clinical implications.

Combined Inferior Vena Cavography, Iliac Venography, and Lung Imaging with99mTc Albumin Macroaggregates

Abstract The author describes a technique for visualizing the iliac veins, inferior vena cava, and lungs to locate thrombi and pulmonary thromboembolism. Bilateral simultaneous injection of the pedal veins with 99mTc macroaggregates of human serum albumin and rapid-sequence pictures of the abdomen with a gamma-ray scintillation camera are followed by lung scintiphotography using the same injected material. The method has been successful in uncovering occult thrombi and pulmonary thromboembolism and is recommended as a screening and monitoring procedure for patients who may have these difficulties.

Serial brain scanning with radioactive xenon and scintillation camera.

SERIAL BRAIN SCANNING WITH RADIOACTIVE XENON AND SCINTILLATION CAMERAJYOJI HANDA, M.D., HAJIME HANDA, M.D., KANJI TORIZUKA, M.D., KEN HAMAMOTO, M.D. and TADAKO KOUSAKAAudio Available | Share

The use of sodium 11C-benzoate in renal visualization

Carbon-11 is a positron emitting radionuclide with a half-life of 20·4 min. The rapid decay permits the administration of relatively large quantities of 11C-labeled compounds with small radiation dose to the patient. The emission of positrons by carbon-11 provides for great discrimination in determining its localization in the body, because of the high resolution provided by positron cameras in visualization of the source of annihilation radiations. To utilize these advantages, methods are being developed for the rapid syntheses of medically-useful 11C-labeled compounds. In the present communication, the use of sodium 11C-benzoate in renal visualization is reported. Deuteron bombardment of a B 2O 3 target results in the 10 B(d, n) 11 C reaction which yields 11CO and 11CO 2 that are liberated from the target by recoil. The 11CO is oxidized to 11CO 2 in the gas phase which is then reacted with phenylmagnesium bromide. After acid hydrolysis and extraction with NaHCO 3, sodium 11C-benzoate is produced. The yield is 60–80 per cent of the carbon-11 trapped in the ethereal solution of the Grignard reagent. The time required is 10–20 min. When the 11C-benzoate is injected intravenously in dogs, the carbon-11 appears rapidly in the kidneys. Positron camera pictures of the kidneys demonstrate a sufficiently long parenchymal filling phase, during the first 10 min after injection, to allow for tomographic visualization of the renal parenchyma. This procedure has advantages over 203Hg-chlormerodrin for the detection of a lesion in the kidney. Positron camera tomograms taken during the filling phase of the renal pelvis also show greater detail than is the case when 131I-iodohippurate is used with the gamma-ray scintillation camera.

SERIAL BRAIN SCANNING WITH TECHNETIUM 99m AND SCINTILLATION CAMERA

SERIAL BRAIN SCANNING WITH TECHNETIUM 99m AND SCINTILLATION CAMERAJYOJI HANDA, M.D., SACHIO NABESHIMA, M.D., HAJIME HANDA, M.D., KEN HAMAMOTO, M.D., TADAKO KOUSAKA and KANJI TORIZUKA, M.D.Audio Available | Share

Combined radiocontrast and radionuclide cerebral angiography.

An assessment of serial brain scans obtained at one-second intervals following a carotid injection of radiopertechne-tate was initiated to determine its value as a supplement to contrast cerebral angiography (1, 2). Twenty-five patients had the radiopertechnetate administered immediately following cerebral angiography through the same carotid puncture. The analysis of these cases forms the basis of this report. Method and Material The entire angiographic procedure was performed with the patient under general anesthesia. After the radiographic component of the examination was completed, the patient was positioned under the gamma-ray scintillation camera (Pho/ Gamma II, Nuclear-Chicago). Rapid sequence scans were first obtained in the lateral projection following a 10-millicurie radiopertechnetate (Na99mTc04) carotid injection. A frontal series was procured immediately afterward with an additional 10-millicurie injection. The Robot time-lapse camera was set to take serial 0.8-second exposures, and concomitantly the Polaroid film pack was pulled manually as quickly as possible. On the average, it takes ten to thirteen seconds to obtain the eight Polaroid scintiphotographs. The Robot camera was loaded with Kodak Panatomic-X film, and it requires approximately two-tenths second to advance the film between exposures. The radiopertechnetate was diluted to a volume of 10 ml with normal saline and injected briskly by hand through a short length of tubing into a No. 18 Cournand needle. Tubing is necessary to permit the operator to work clear of the gamma camera detector head. Of the 25 patients, 6 had tumor, 11 had cerebral vascular disease, 6 were normal, and there was one each f head trauma and arteriovenous malformation. Results Normallateral and frontal sequences are illustrated in Figure 1. The lateral view was obtained first, and there is no significant interference of the radiopertechnetate background in the quality of the frontal projections. The frontal projections are useful in establishing relative blood flows between the anterior and middle cerebral arteries. The patient illustrated in Figure 2 was shown by contrast angiography to have an occlusion of the right middle cerebral artery at its origin.

Radionuclide Diagnosis of Arteriovenous Malformations with Rapid Sequence Brain Scans

THERE HAVE BEEN discussions in the literature on what is the appropriate length of time to wait between administration of a radiopharmaceutical and scanning of the brain in order best to portray an arteriovenous malformation. It is generally conceded that there is a higher frequency of detection with early scanning because it is primarily the blood pool that is being visualized and not radioactive material diffusing across a disrupted bloodbrain barrier (1–4). The appearance of the arteriovenous malformation on the scan, however, is not definitive and may simulate a neoplasm, infarct, intracerebral hematoma, or other less common causes of positive results. It has been our experience that a characteristically high concentration of radioactivity can be observed passing through the malformation when serial five-second-exposure scintiphotos are taken with the gamma-ray scintillation camera immediately after an intravenous injection of radiopertechnetate (5). The concentration observed in the malformation with...

Intravenous radioisotope angiography using 113mInFeDTPA-ascorbic acid.

AN IDEAL combination of the rapid imaging properties of the gamma-ray scintillation camera and a large dose of a short-lived nuclide makes possible a dynamic study of the heart, the major blood vessels, and the kidneys by a simple intravenous injection. It is suggested that this new diagnostic method be named intravenous radioisotope angiography inasmuch as it provides morphologic information similar to that of x-ray angiography. The method itself was initiated by Rosenthall who employed 99mTc pertechnetate as a test agent (1, 2). While 99mTc has many advantageous physical properties, it is not convenient in Japan, owing to the relatively short shelf life of the 99Mo-99mTc generator. The 113Sn-113mIn generator, however, has a long shelf life, and recently we have succeeded in obtaining good radioisotope angiograms with 113mIn. Our preliminary results with 113mInFe DTPA-ascorbic acid are reported in this communication. Methods and Materials Radioisotope angiography was performed with the Pho/Gamma camera m...

Radionuclide imaging of the uterus with special reference to pregnancy.

The feasibility of using technetium-99m as a pertechnetate or strontium-87m to visualize and localize the placenta with the gamma-ray scintillation camera was demonstrated in a previous communication (2). It was shown that a frontal and lateral view of the placenta can be accomplished within eight minutes of an intravenous injection of one millicurie of radioactivity and be accurately localized relative to a radionuclide marker over the symphysis pubis. Large areas of reduced or absent perfusion of the placenta may be detected, particularly when implanted on the anterior wall of the uterus. An extension of this early study is presented in this report. The uterus was scanned in various stages of pregnancy, in the presence of fibroids, and in a single case of hydatidiform mole. Method and Material The results to be reported were selected from 150 scans of the uterus in the first, second, and third trimesters of gestation. All were performed either with technetium-99m pertechnetate (99mTcO4) or strontium-87m (87mSr) and the gamma-ray scintillation camera. The patients were premedicated with an oral dose of 250 mg potassium perchlorate one hour prior to the administration of 99mTcO4. No premedication was offered when 87mSr was used as the test agent. Point sources (57Co or 131I) were taped over the superior part of the symphysis pubis and the umbilicus. About 4,000 counts were accumulated with the gamma camera detector positioned vertically over the abdomen while the patient was lying supine. The radionuclide markers were then removed, but the polaroid film on which the 2 Pho/Gamma, Nuclear-Chicago. image was recorded was not. One millicurie of 99mTcO4 or 87mSr was injected intravenously, and an additional 100,000 counts were accumulated. The resultant frontal view therefore portrayed the placental blood pool and its relationship to the the pubic and umbilical markers. This was followed by a lateral scintiphoto, which was obtained by rotating the detector head to a horizontal attitude, rather than turning the patient. If a low-lying placenta was visualized, a more accurate assessment of its relationship to the cervix was obtained by inserting an intravaginal radionuclide marker. Our method is to tape an 131I capsule onto the end of a tongue depressor. The unit is then ensheathed in a sterile condom, lubricated, and gently inserted into the vagina along the posterior wall as far as it will go. A similar source is placed over the pubis. Frontal and lateral projections are obtained and then are superimposed on the scintiphoto of the placenta so that the distance between the cervix and placental margin can be estimated. When the patient is in the late first or early second trimester, a suprapubic marker may obscure the uterine contents.

Radionuclide diagnosis of malignant tumors of the kidney.

RADIONUCLIDE DIAGNOSIS OF MALIGNANT TUMORS OF THE KIDNEYLEONARD ROSENTHALL, M.D.Audio Available | Share

Radioxenon Brain Scanning with the Gamma-Ray Scintillation Camera

Cerebral blood flow has been studied with Xe133 (2, 4) and Kr85 (3) by externally monitoring the rate of disappearance of the radionuclide from the brain after inhalation of the gas or after a carotid artery injection of the gas dissolved in saline. The desaturation curves obtained with Xe133 consist of two (4) or three (2) exponential components; a fast component of T½ one and a half minutes and a slow component of T½ ten minutes (4). These purportedly reflect the cortical and white matter blood flow, respectively. The relatively quick disappearance of the radionuclide precludes scanning by conventional rectilinear apparatus, but the gamma-ray scintillation camera (Pho/Gamma, Nuclear-Chicago) is capable of imaging the brain in as short a time as thirty seconds for the dose of Xe133 used. This feature permitted an investigation of Xe133 as a test agent for scanning. It was administered via the carotid artery and/or inhalation, and a comparison was made, when possible, with the brain scan obtained with macroaggregates of radioiodinated albumin (MARIA) (5, 6). Fifteen patients received the intracarotid injection of Xe133. Their lesions consisted of primary and secondary tumor, cerebral hematoma, and transient vascular ischemia. Method and Material The Xe133 gas was administered through a closed-system device improvised from a discarded McKesson anesthetic gas apparatus. About 15 mCi Xe133 were used, and the expired carbon dioxide was absorbed from the gaseous mixture. A face mask was applied to semicomatose patients; otherwise a mouthpiece was preferred. The patient was instructed to breathe normally. Imaging with the gamma camera commenced when a steady state was reached. Following this, the gas mixture was shunted to a collecting bag, and room air was admitted for inhalation. Two or three 2-minute exposure scintiphotos were obtained during this desaturation phase. Approximately 10 mCi Xe133 dissolved in 10–20 ml of saline was injected into the carotid artery over a thirty-second interval. The gamma camera was set to image the brain during this injection period, and serial half- to one-minute exposure scintiphotos were obtained during the washout. The MARIA was injected into the carotid artery following the xenon-solution study when the two procedures were combined. Approximately 150 μC I131, containing about 1 mg of albumin, was the usual dose. The particle size ranged from 5 to 30 microns in diameter. Results An example of a normal occipital and left lateral Xe133 ventilation scan obtained during the steady state is shown in Figure 1. The results of scans of 6 patients are shown in Figures 2–7. It will be seen that a recurring theme in the case histories is that in spite of the tumor being relatively avascular and cystic, the amount of Xe133 diffusing into the area did not differ greatly from that in the adjacent tissue. Discussion With MARIA injections, the macroaggregates are trapped in the capillaries or distal arterioles.

Radionuclide venography using technetium 99m pertechnetate and the gamma-ray scintillation camera.

RADIONUCLIDE VENOGRAPHY USING TECHNETIUM 99m PERTECHNETATE AND THE GAMMA-RAY SCINTILLATION CAMERALEONARD ROSENTHALL, M.D.Audio Available | Share

Ortho-iodohippurate-I-131 kidney scanning in renal failure.

Hippuran (ortho-iodohippurate) labeled with I131 or I125 has been employed with good success in the study of some parameters of renal function. Although eminently suitable for the renogram, its rapid excretion makes renal scanning difficult with conventional automatic scintillation scanners. Constant infusion (2) and stop-flow (3) technics have been advocated, but these are impractical. Wenzl et al. (4) suggested its use to localize the site of ureteral obstruction. RadioNeohydrin, which is slowly excreted, has therefore almost completely supplanted Hippuran as a scanning agent. The acquisition2 of a gamma-ray scintillation camera (1) revived our interest in the excretion patterns of Hippuran in both normal and abnormal kidneys. In the course of obtaining serial two-or threeminute exposure scintiphotos after an intravenous injection of 200 microcuries of Hippuran, it was noted that some cases of renal failure showed a high concentration of Hippuran which remained relatively fixed in the renal parenchyma. ...

Applications of the gamma-ray scintillation camera to dynamic studies in man.

The gamma-ray scintillation camera used in these studies was the Pho/Gamma manufactured by Nuclear-Chicago and adequately described by Anger (1–3) in a number of communications. This apparatus represents a distinct advantage over the conventional automatic scintillation scanner. The conventional scanner covers a given point briefly during its transverse, and a relatively high count rate is required to discriminate variations of concentration within an organ. On the other hand, the gamma camera sees each point continuously within its 9-in. diameter useful field and can be set to record as many total counts as are necessary to visualize these variations. For the usual dose of radioactive test agent employed in conventional automatic scintillation scanning the gamma camera can visualize the target in one-fifth to one-twentieth of the time of the conventional. Conversely, much smaller test doses and longer recording times can be used with the gamma camera, with reduced radiation exposure to the patient (4). A...

Renal Scintiphotography with the Gamma-Ray Scintillation Camera and Hg203-Neohydrin

Renal scanning is a valuable clinical procedure. It is particularly useful for (a) detecting masses in the kidneys, (b) identifying the degree of parenchymal function, often possible when there is nonvisualization on intravenous pyelograms, (c) distinguishing between lesions and anatomic variations, such as fetal lobulation, (d) localizing the kidneys prior to biopsy, and (e) demonstrating unilateral vascular or other segmental diseases. In a series of patients with renal vascular disease, the Hg203-Neohydrin scintiscan had a diagnostic accuracy of 80 per cent, second only to aortography in reliability (9). Renal scanning was initially performed with a continuous infusion of I131-Hippuran (7). Temporary ureteral obstruction— the “stop-flow” technic—helped to improve the quality of the scans (10), but complicated the examination. With the introduction of Hg203-Neohydrin for brain scanning (3, 4) and its subsequent use in renal scanning (12), this agent has become widely employed in both. Renal scans with Hg203-Neohydrin have proved to be of greater diagnostic value than those obtained with I131-Hippuran (8, 9). Conventional scintiscanning of the kidneys is usually performed one to two hours after an intravenous dose of 100–150 microcuries of Hg203-Neohydrin. About 60 per cent of the agent is fixed by the renal tubules in this period. Scanning time is about forty-five minutes (14), and the total renal irradiation has been variously estimated to range from about 8 to 20 rads (5, 11, 13). Hg197-Neohydrin lowers this value because of its short half-life (13). Hg197 has soft 67–78 Kev photons (6) which are more readily scattered in tissue, however, and it is not yet known how this will affect the diagnostic accuracy of the scans. In spite of the recognized clinical worth of renal scintiscanning, the length of time required to perform the procedure with conventional focused collimator scanners imposes restrictions on the examination. Usually, only a single view is obtained, and the patient must be able to co-operate sufficiently to remain still throughout the study. With the newly developed scintillation camera, however, the examination time can be reduced by a factor of 10. The purpose of this article is to describe the use of the scintillation camera in renal scanning and to demonstrate the increased clinical scope possible when the shorter exposure times are exploited. The Gamma-Ray Scintillation Camera The scintillation camera produces pictures similar to those made by a conventional radioisotope scanner, but the camera does not scan in the usual sense. For renal scintiphotography, a multichannel collimator projects gamma-ray images of the kidneys onto a scintillation crystal. The collimator is composed of a lead plate with 1,000 or more parallel holes. The field of view of the scintillation camera is 9–10 in. in diameter, and the sensitivity is such that 1 microcurie, of Hg203 produces 150 dots a minute on the picture.