Journal of nuclear biology and medicine (Turin, Italy : 1991)最新文献

The proposed method can be used for reconstructing, from n not necessarily equidistant points of a digitized polydrome line, a set of n1 equidistant points (with n1 > n) interpolating the original points. This method is based on a transformation of the original line into a digitized monodrome function D(1i) (unrolling function), where 1i is the line length between the origin and the ith point (i = 1,..., n1). Advantage of this method consists in reducing the two-dimensional interpolation problem to the one-dimensional field. In scintigraphic imaging, it is possible to achieve interpolation and coding of ROI's (Regions Of Interest) edges. For n samples of a monodrome line this method can also be applied, representing a possible alternative to splines. The numerical procedure is developed to reduce the noise on the points.

The aim of this study was to clarify the significance of enhanced thallium-201 (201Tl) uptake after reinjection following 4-hour redistribution imaging. Thirty-four patients with coronary artery disease (CAD) and left ventricular (LV) dysfunction (ejection fraction 32 +/- 10%) underwent exercise-redistribution (ER) 201Tl scintigraphy with rest injection, resting technetium-99m methoxy isobutyl isonitrile (MIBI) imaging, 2D-echocardiography, and coronary angiography. Wall motion (WM) was graded on echocardiographic images. A total of 510 myocardial segments were quantitatively analyzed. A total of 267 (52%) segments had normal (N) 201Tl uptake, 53 (10%) reversible (RD), and 190 (37%) irreversible (ID) 201Tl defects on ER images. Of these 190 ID, 84 (44%) showed enhanced 201Tl uptake after reinjection (Re+) and 106 (56%) remained unchanged after reinjection (Re-). MIBI uptake was significantly higher in RD compared to Re+ and Re- (both p < 0.01), and in Re+ compared to Re- (p < 0.01). The WM score was significantly lower in RD and Re+ compared to Re- (p < 0.01), while no difference was observed between RD and Re+. The severity of coronary artery stenosis was significantly lower in RD compared to Re+ and Re- (both p < 0.01), but no difference was observed between Re+ and Re-. The occurrence of collaterals was significantly higher (p < 0.01) in Re+ (69%) compared to Re- (38%). In conclusion, in patients with CAD and impaired LV function, enhanced 201Tl uptake after reinjection in myocardial segments with ID on ER images was associated with less severe WM abnormalities, higher MIBI uptake and the presence of collaterals.(ABSTRACT TRUNCATED AT 250 WORDS)

The phospholipid ether analog, [125I]-1-O-[12-(m-iodophenyl)dodecyl]propanediol-3-phosphocholine (NM-295) was synthesized and evaluated for its ability to visualize tumors. Preliminary studies were performed in rats bearing the Walker 256 carcinosarcoma. Most of the radioactivity was cleared from the animals during the first 24 hours. However, the tumor showed a decreased rate of clearance of radioactivity when compared with non-target tissue. This difference in the clearance rate allowed for excellent images of the tumor at 24 hours. Scintigraphic images compared favorably with other radioiodinated phospholipid ether analogs such as [125I-rac-1-O-[12-(m-iodophenyl)dodecyl]-2-O-methylglycero-3- phosphocholine (NM-294) and [125I]-12-(m-iodophenyl)dodecyl phosphocholine (NM-324). In contrast with the latter two compounds, however, tissue distribution studies revealed that NM-295 cleared at a much faster rate from all tissues, including tumor. In addition, within 24 hours following administration of NM-295, over 70% of the radioactivity was excreted as compared to 50% and 20% for NM-294 and NM-324, respectively. The majority of excreted radioactivity appeared in the urine for all three compounds. Thin-layer chromatography of urine and fecal extracts showed the presence of metabolites only. In contrast, lipid extracts of either liver or tumor demonstrated only the presence of the parent compound. Therefore, these data suggest that in each case it was the parent phospholipid analog that was taken up and retained by the tissues, while the metabolic product(s) was cleared and excreted from the animal.

Radiolabelled MoAbs have been used in both the diagnosis and the treatment of a variety of tumors. Recently, a three-step tumor pre-targeting strategy has been proposed to overcome one of the major limiting factors in radioimmunodetection: the low tumor-to-background ratio. We evaluated this pre-targeting protocol in 10 patients diagnosed as having pulmonary carcinoma. One milligram of biotinylated anti-CEA MoAb (FO23C5) was administered i.v. (1st step); 24 hours later 5 mg of avidin was injected i.v. (2nd step) followed by 100-500 ng of 111In-biotin (5 mCi) the day after (3rd step). Imaging was performed using single photon emission tomography (SPET). No toxicity and no adverse reactions were observed. Tumor was detected in 8 out of 10 patients. Mediastinal metastases were also localised in 2 out of 3 patients, and adrenal gland recurrency in 1 out of 2 patients. The tumor/background (normal lung), heart, liver and spine ratios were respectively 2.0, 1.0, 1.3 and 4.1 at 90 minutes post-injection. These preliminary data show that the three-step pretargeting method is safe and allows SPECT tumor localization soon after the injection of the radiolabel. In the future, the use of MoAbs with higher specificity could result in improved tumor-targeting, and in the possibility of lung cancer radioimmunotherapy.

Abrupt onset of scrotal symptoms is a not uncommon condition, particularly in the paediatric age, which raises the problem of a rapid decision concerning proper therapeutic management (i.e. surgery or pharmacotherapy); the testicular radionuclide scan is generally considered to be helpful in making this choice, as it is theoretically able to distinguish between hypervascular (inflammation) and hypovascular conditions (testicular torsion). We report our experience in paediatric patients presenting acute scrotum. Thirty consecutive cases were examined, but three were discarded because of their non-routine features. Our records show that torsion of the appendix testis is far from uncommon (6 cases out of 27); however, the scintigraphic pattern of this pathological condition, which usually does not require urgent surgical treatment, does not seem to differ greatly from that of scrotal inflammation. Of the remaining 21 cases, 15 were correctly diagnosed, while 4 were to be considered non-diagnostic because of the presence of hypovascular scrotal conditions other than testicular torsion. We conclude that, while not always a very precise tool for the diagnosis of acute scrotum, nevertheless testicular scan results may be considered a useful parameter in choosing the proper type of treatment.

Serial colon scintigraphy using 111In-DTPA (2 MBq) given orally was performed in 39 children referred for constipation, and the total and segmental colon transit times were measured. The bowel movements during the study were recorded and the intervals between defecations (ID) were calculated. This method proved able to identify children with normal colon morphology (no. = 32) and those with dolichocolon (no. = 7). Normal children were not included for ethical reasons and we used the normal range determined by others using x-ray methods (29 +/- 4 hours). Total and segmental colon transit times were found to be prolonged in all children with dolichocolon (TC: 113.55 +/- 41.20 hours; RC: 39.85 +/- 26.39 hours; LC: 43.05 +/- 18.30 hours; RS: 30.66 +/- 26.89 hours). In the group of children with a normal colon shape, 13 presented total and segmental colon transit times within the referred normal value (TC: 27.79 +/- 4.10 hours; RC: 9.11 +/- 2.53 hours; LC: 9.80 +/- 3.50 hours; RS: 8.88 +/- 4.09 hours) and normal bowel function (ID: 23.37 +/- 5.93 hours). In the remaining children, 5 presented prolonged retention in the rectum (RS: 53.36 +/- 29.66 hours), and 14 a prolonged transit time in all segments. A good correlation was found between the transit time and bowel function. From the point of view of radiation dosimetry, the most heavily irradiated organs were the lower large intestine and the ovaries, and the level of radiation burden depended on the colon transit time. We can conclude that the described method results safe, accurate and fully diagnostic.

Pathophysiological changes in ureteral kinetics can be monitored externally and non-invasively by means of a time-space matrix approach during the excretory phase of fast-frame routine renography. The main limitations of this method are poor space-time resolution and, in some cases, an inadequate visualization of the peristaltic waves. A new approach to the study of ureteral contractions using the power spectrum obtained from Fourier transforms of the ureteral time-activity curves was developed. The FORTRAN program was tested by an experimental simulation, and its subsequent application on fifty-one subjects indicated that the method is a useful complement to the space-time matrix technique. Moreover, evaluation of the power spectrum offers several advantages for the study of the pathophysiological parameters of peristalsis.