Vol.13,

A rational analysis procedure for solitary lesions on whole bone scanning was offered. This study was undertaken to analyze retrospectively solitary lesions which obtained final diagnose through the following aspects: (1) diagnosis of bone metastasis, (2) the incidence of bone metastasis in different tumor, (3) the most possible lesion sites indicating bone metastasis, (4) morphological analysis of solitary lesions. The results are: (1) The incidence of solitary lesions in 2465 cases on whole bone scanning is 15.3%. (2) The rate of bone metastasis is 24.8% in 282 patients with primary malignancy. The rate of bone metastasis is 6.3% in 64 patients without primary malignancy, and the total diagnostic rate of bone metastasis is 21.4% in 346 patients. (3) In patients with primary malignancy, the incidence of bone metastasis of solitary lesions is as follows respectively: bronchi cancer 36.1%(22/61); breast cancer 23.8%(20/84); prostate gland 17.2%(5/29); other urinary system cancer 22.2%(4/18): G.I. system cancer 16.9%(10/59); others 29.0%(9/31). There is no significant difference in different cancer. (4) In patients without primary malignancy, 93.7%(60/64) of solitary lesions are benign. (5) From anatomical point of view, we found the diagnostic rate of bone metastasis is as follow: 30% in spine; 34.2% in pelvis; 36.4% in skull; 10.8% in other bones. There are significant differences in four groups. It is concluded that: (1) The diagnostic rate of bone metastasis in solitary lesions is 21.4%. (2) The most possible solitary lesions indicating osseous tumor spread are at spine, pelvic and skull. (3) Special attention to "cold" and streak like lesions should be paid. (4) A clinical analysis procedure for diagnosis of solitary lesions has been summarized out here.

273

In order to investigate the changes of regional cerebral blood flow (rCBF) in patients with acquired immunodeficiency syndromes (AIDS), ^99mTc-ECD brain SPECT imaging was performed in 5 patients with AIDS and 16 sex and age matched normal controls, and the rCBF percentages compared to the cerebellum were calculated using a semi-quantitative processing software. Hypoperfusions in the right and left frontal, temporal, porietal lobe, basal ganglia and left thalamus were seen in 1 patient with dementia. Hypoperfusions in the right and left frontal and temporal lobe were seen in 4 asymptomatic patients. The rCBF in the right and left frontal, temporal, porietal lobe, basal ganglia and thalamus, front and pons were decreased significantly in patients with AIDS than those of the control subjects (p<0.005). It is concluded that there exists reduced cortico-subcortical rCBF in AIDS patients.

346

In order to study the image characteristics of motion artifacts and to determine the relations of motion artifacts with varied motion types, and the imaging timings, frames, distances and directions during SPECT acquisition, a myocardial phantom filled with pertechnetate solution was used to simulate the patient motion. In nonreturning pattern, the simulation motion was timed at the 0°, -45° and -90° positions during the rotation of the detector over a 180° are from +45° right anterior oblique to -135° left posterior oblique. Simulation motion was performed by moving the phantom ±5mm, ±10mm and ±20mm along X- (from left to right), Y- (from head to caudal) and Z-axis (from back to ventral) respectively. In returning pattern the acquired 30 projections were divided into three equal parts. The simulation motion was timed at the middle 1-7 projections of each part and performed by moving the phantom ±5, ±10, ±15, ±20, ±25, ±30 and ±50 mm along X-, Y- and Z-axis respectively. Each image was compared with normal image and assessed by three experienced observers without knowledge of the phantom motion. Logistic regression analysis was used to determine the relationship of motion artifacts with the affecting factors. No significant artifacts can be found when the phantom was moved slightly, no matter which motion pattern, direction and timing were taken. The characteristics of motion artifacts showed a radioactive marker dot in inferior wall firstly when the phantom was moved along X-axis. Septal and lateral wall became "hot" symmetrically when the phantom was moved along Y-axis. And nodular hot could be found in anterior wall when the phantom was moved along Z-axis. At last the "lumpy" and "defect" areas existed alternately and formed a triangle respectively. The presence of motion artifacts was related to motion directions, distance and affected frames, but was independent of motion timing. The characteristics of motion artifacts could be found when the phantom was moved along different axis. Motion distance contributed more to the appearance of motion artifacts than other related factors, this was especially clear when motion was along Y-axis.

296

Nicotinic acetylcholine receptors (nChRs) are involved in the various pharmacological effects or disease states. In order to study the central nChRs by PET or SPECT, some radioligands have been investigated. In this paper, the procedure for synthesis of 2-[¹⁸F]fluoro-3-[2(S)-2-azetidinylmethoxy]pyridine (2-[¹⁸F]-A-85380), a potential PET ligand for in vivo imaging nicotinic acetylcholine receptor was described. 2-[¹⁸F]-A-85380 was prepared from the precursor, 2-nitro-3-[(1-(tert-butoxycarbonyl)-2-(S)-azetidinyl)methoxy]pyridine(4), which was synthesized with commercial (S)-2-azetid- inecarboxylic acid as starting material. The whole procedure for radiosynthesis and purification was executed in about 1h and 45-55% of the added fluorine-18 was found in the purified 2-[¹⁸F]-A-85380, with specific activity of 1.0-2.2×10¹¹ Bq/μmol.

262

298

Tin-117m(t_1/2 14d; γ 159keV, 86%) is an ideal tracer for studying biological behavior of tin compounds as well as for developing clinically-useful radio-pharmaceuticals. It had been reported that Sn-117m[4+] DTPA has unexpectedly high bone uptake and bone-to-blood ratio, and is potentially useful as an agent for skeletal scintigraphy and radiotherapy of bone tumors. In this work, HEDTMP [N-(2-hydroxyethyl) ethlenediamine-1,1,2-tri (methylene phosphonic acid)] was synthesized. Let it form complex with ^117mSn. The formation conditions, stability and distribution coefficient between oil and water of the complex were investigated.

270

The properties of radicals from γ-ray irradiated silk fabrics were studied by electron spin resonance method (ESR). The ESR spectra of silk fabrics irradiated in N2 showed a doublet at room temperature. The doublet became a singlet at g=2.0057 after placing the sample in air for 24 hours. This can be explained by formation of peroxide radicals. The radical concentration of the irradiated silk fabric and the decay rate of radicals are significantly affected by irradiation conditions, which include the absorbed dose, atmosphere, and water content of the silk fabric samples. However, no dose rate effect on the radical concentration was observed. The results are of help in our practice of property modification of silk products by radiation graft copolymerization.

492

Experimental studies were carried out on the purification of eutrophic Taihu Lake water by dynamic experiment using immobilized nitrogen cycle bacteria (INCB). The results showed that the eutrophic water of Taihu Lake can be purified effectively as it passes through the experimental reactor into which some immobilized nitrogen cycle bacteria were put. The removal efficiencies for Total N (TN), NH4+-N with immobilized nitrogen cycle bacteria were 72.4% and 85.6%, respectively. It was found that the immobilized nitrogen cycle bacteria also have purificatory effect on eutrophic water of Taihu Lake at winter temperature (7°C), and that the removalm efficiencies for Total N (TN), NH4+-N were 55.6%, and 58.9%, respectively. The removal efficiencies for TN and NH4+-N depend on the time the water stays in the experimental reactor.

534

The activities of protactinium were produced by the multi-nucleon transfer reactions in bombardment of the natural uranium with 60 MeV/nucleon ¹⁸O ions. A simple, relatively fast radiochemical procedure was used for extraction separation of protactinium from the uranium and a variety of reaction products using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and tri-iso-octylamine as extractants. The γ ray spectrum of the separated protactinium fractions showed that the protactinium could be separated from all of the main impurity elements. The decontamination factors of the uranium and the main reaction products produced in the reaction are given.

451

337