Vol.16,

224

The picosecond accelerator (PA) is a low energy electron linear accelerator facility under commissioning, which is built for the experiment of ps level pulse radiolysis in Shanghai Institute of Applied Physics (SINAP). A practical distributed DA&C system for this facility has been developed. In view of the upgrading-ability and maintainability of the control system and controlled devices, Advantech© distributed intelligent DA&C products are adopted into the control system. ADAM 5000/TCPs with the protocol of Modbus/TCP are employed to accomplish data acquisition and device control. The PC-compatible programmable logic controller, ADAM-5511, is also adopted to handle the interlocks and the emergency events. On the software side, the integrated software package King-view©V6.5, which friendly supports all Advantech products, has been used to develop the upper layer control logic and process the data. This paper describes the control system design and system architecture. The intelligent ADAM controllers and the software platform are also discussed in detail.

296

The bystander effects induced by medium from human hepatoma SMMC-7721 and adenocarcinoma F56 cells irradiated with carbon ions were investigated. It was found that the survival fraction (SF) of the irradiated cells decreased exponentially along with the increased dose. SMMC-7721 cells were more radiosensitive than F56 cells. The plating efficiency (PE) of the non-irradiated cells treated with irradiated conditioned medium (ICM) was obviously lower than the PE of control cells for SMMC-7721 cells but not for F56 cells. Moreover, the reduced PE and SF by ICM treatment were more significant for 1Gy irradiation than for 6Gy irradiation on SMMC-7721 cells. These results suggest that the irradiated cells can secrete factor(s) into medium that is cytotoxic to bystander non-irradiated cells. The bystander effects are dependent on cell genotype presented at the time of irradiation and radiation dose. This makes impact on the precise estimation of the effects of radiation and tumor radiotherapy.

361

The heavy ions with high linear energy transfer and high relative biological effectiveness are much more deleterious on the male germ cells, ones of the most radiosensitive cells of the body, than low-LET ionizing radiation such as X-ray or gamma-ray. The effects of low-dose heavy ion irradiation on male germ cell adaptation and genetics and the possible mechanism of this adaptation are summarized in our laboratory. Our results showed that the heavy ion irradiation significantly increased the frequencies of chromosomal aberrations in spermatogonia and spermatocytes of mice, the low dose heavy ion irradiation could induce significant adaptative response on mouse testes and human sperm, and pre-exposure of mouse testes with low-dose heavy ion can markedly alleviate damage effects induced by subsequent high-dose irradiation. The increase of SOD activity and decrease of lipid peroxidation levels induced by low-dose ionizing radiation may be involved in this adaptative response mechanism. These studies may provide useful theoretical and clinical bases for radioprotection of reproductive potential and assessment of genetic risks for human exposed to heavy ions in radiotherapy and in outer space environment.

201

To monitor the extent and the duration of lymphocyte subset changes in patients with thyroid carcinoma undergoing therapeutic ¹³¹I administration, the percentage of lymphocyte subsets were serially analyzed before and after ¹³¹I treatment. In patients who received 1850 MBq of ¹³¹I for ablation of thyroid remnants, only for NK cells and B cells showed a significant reduction. In patients received 3700 MBq of ¹³¹I for treatment of local lymph node metastases, NK cells, B cells and CD4+were found decreased. In patients received 7400 MBq of ¹³¹I for treatment of distant metastases, NK cells, B cells and CD4+ and CD8+ were all affected. However, there is no significant reduction compared to the baseline in the percentage of all lymphocyte subsets three months after ¹³¹I treatment. The results show that the sensitivity of lymphocytes to ¹³¹I internal radiation depends upon lymphocyte phenotype and ¹³¹I activity. The immunosuppression effects are temporary and reversible.

239

To evaluate the clinical value of combined determination of serum PG I , PG II and GAS for early diagnosis of gastric cancer, the serum levels of PG I, PG II and GAS in 190 healthy controls and 129 patients with gastric disorders were measured by RIA. The 129 patients include 68 cases of gastric cancer. The results showed that the serum levels of PG I and PG I /PG II ratio in gastric cancer patients were obviously lower than those in healthy controls, while comparing with controls, the serum GAS levels were significantly higher. The diagnostic accuracy of the determinations for gastric cancer was evaluated by receiver operating characteristic (ROC) curve analysis. The area under the curve (AUC) levels of serum PG I, PG I /PG II ratio and GAS were 0.833, 0.842 and 0.851, respectively. As serum PG I or PG I /PG II ratio or GAS were combined, the sensitivity and specificity of determination for gastric cancer diagnosis were 94.2% and 73.4%, respectively. All these results indicated that the combined determination of serum PG I, PG II and GAS levels may be used as a tool for primary screening of gastric cancer.

389

The study aims to investigate the effect of retinoic acid on the iodide uptake of MCF-7 cells and its mechanism. The iodide uptake and expression of hNIS(human sodium/iodide symporter)mRNA in the breast cancer MCF-7 cells were compared individually before and after the intervention of all-trans retinoic acid (ATRA) with the iodide uptake assay and RT-PCR. The following results are obtained: (1) when treated with all-trans retinoic acid in the concentration of 1.0 µmol/L, the capacity of iodide uptake of MCF-7 cells reached about 1.5 times of the basal state; (2) 12 h after the intervention of 1.0 µmol/L ATRA, the hNISmRNA expression of the MCF-7 cells reached maximum. The study shows that all-trans retinoic acid has the effect to improve the iodide uptake of the MCF-7 cells and this effect may result from its up-regulation of the hNISmRNA expression.

262

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349

The performance of gamma camera with NaI(Tl) array coupled with position sensitive photomultiplier tube (PSPMT) R2486 has been studied. The pixel size of NaI(Tl) crystal is 2mm×2mm and the overall dimension of the array is 48.2mm×48.2mm×5mm. There are 484 pixels in a 22×22 matrix. Because each pixel can produce a much focused light spot and restrict the spread of photons, position resolution of the gamma camera is mainly determined by pixel size. It is shown that crystal array pixel can reduce shrinkage effect and improve intrinsic position resolution greatly via restricting the spread of photons. Experimental results demonstrate that its position resolution and linearity are much improved comparing with the gamma camera using planar crystals coupled with PSPMT.

232

This paper reports methods and results of the investigation of natural radionuclides levels in multiple media in the bone-coal mine areas in Hubei, Hunan, Jiangxi, Zhejiang, and Anhui Provinces. In the studied bone-coal mine areas, the specific activities of ²³⁸U and ²²⁶Ra in the soil samples were 0.37 and 0.24 Bq/g, respectively; the specific activities of ²²⁶Ra in the samples of bone-coal, bone-coal cinder and bone-coal cinder brick (BCCB) were 1.3, 1.4 and 0.9 Bq/g, respectively. In the water samples collected from the bone-coal mine areas, the average concentrations of natural uranium and ²²⁶Ra were 33µg/L and 58 mBq/L, respectively, while in the water samples collected from outside the bone-coal mine areas, they were 3.4µg/L and 45 mBq/L, respectively. In addition, the specific activities of ²³⁸U and ²²⁶Ra in air aerosol samples from the bone-coal mine areas were 0.6 and 0.5 mBq/m³, respectively.

225

This paper introduces the resident's additional dose in bone-coal mining areas. The increase of the annual additional effective doses accepted by the residents living in the carbide-brick houses, the staffs working in the carbide-brick houses and the miners working in the bone-coal mining areas of Hubei, Hunan, Jiangxi, Zhejiang and Anhui Provinces is caused by the rising of environmental radioactive level. The investigation of natural background radiation in the bone-coal mining areas indicated that both mining and utilizing bone-coal cause the rise of environmental radioactive level. The ranges of the annual additional effective dose accepted by the residents, staffs and miners is 1.9——6.8 mSv, 0.5——2.0 mSv and 8.2——71 mSv, and with an average of 3.8 mSv, 1 mSv and 40 mSv, respectively. The annual additional effective doses accepted by part residents and staffs exceed the dose limit of 1 mSv for public exposure, and part miners exceed the dose limit of 20 mSv for occupational exposure. And the contribution of dose caused by inhaled radon to the total additional effective dose is over 76%.

232

During 1991-1993, the radioactivity levels of the bone-coal mines were investigated in Hubei, Hunan, Jiangxi, Zhejiang and Anhui Provinces, respectively, where the reserve of bone-coal is about 90% of our country's total reserve. The annual additional collective dose equivalent within 80km evaluated region of bone-coal power stations in Nijiangkou and Anren is 1.7 and 1.9 man·mSv, respectively, and that of Zhuantanyan bone-coal shaft is 1.4 man·mSv. The collective dose equivalent caused by bone-coal cinder brick produced for 25 years in the five provinces is 1.6×10⁵ man·Sv.

231