Comparison of radiation doses between hepatic artery infusion chemotherapy and transarterial chemoembolization for liver cancer

Objective:To analyze the radiation dose received by patients during hepatic artery infusion chemotherapy(HAIC)and transarterial chemoembolization(TACE)procedures and the related influencing factors.Methods:Data of 162 cases in the HAIC group and 230 cases in the TACE group were collected.The included covariates were Age(<45/45-59/≥60 years),BMI levels(underweight/normal weight/obesity),focus Dye of tumor(present/absent),lesion size(<5 cm/≥5 cm),superselection(present/absent),hepatic vascular variation(present/absent).The endpoints were postoperative dose-area product(DAP),exposure time and Air kerma(AK).Results:Of all included patients,the HAIC group patients were younger than those in the TACE group(P=0.028).The proportion of patients with large lesions in the HAIC group was higher than the TACE group(45.7%vs.33.9%,P=0.019).The proportion of patients who had superselection was lower in the HAIC group as compared to the TACE group(61.7%vs.82.2%,P<0.001).Generally,the HAIC group has lower DAP,exposure time and AK by 36.3%(P<0.001),38.2%(P<0.001),and 41.3%(P<0.001)than the TACE group,respectively.Linear regression analysis showed the procedure method(HAIC/TACE,P<0.001),type of DSA machine(Pheno/FD20,P<0.001),BMI levels(P<0.001),age(P=0.021),lesion size(<5 cm/≥5 cm,P=0.031)significantly correlated with low DAP.In the HAIC group,the type of DSA machine and BMI correlated with the radiation dose,while in the TACE group,the type of DSA machine,BMI,and lesion size correlated with the radiation dose.Conclusion:Compared with TACE,HAIC enables doctors and patients to receive lower radiation doses.Obese patients in both HAIC and TACE groups increase the radiation exposure in interventional doctors and patients,but large lesions only affect the radiation dose in the TACE procedure.

Evaluation of the Fetal-Maternal Radiation Doses in CT-Pelvimetry and Estimation of the Fetal Radiation Risks in 03 Radiology Departments in Douala-Cameroon

Background: CT in pregnant patients requires careful consideration of the radiation dose and corresponding radiation risks from ionizing radiation to the unborn child. The determination of foetal dose in diagnostic radiology is of interest as a basis for risk estimates from medical exposure of the pregnant patient. Objective: To evaluate the foetal-maternal radiation doses delivered during the CT-Pelvimetry procedure and to estimate the risk to the unborn child to develop a cancer in childhood and hereditary disease. Materials and Methods: We investigate the foetal-maternal radiation doses during CT-scan Pelvimetry in Douala (Cameroon). Data of 194 helical acquisition CT-Pelvimetry were collected between May 2017 and May 2019. An average DLP for the examination was established and the average effective dose was evaluated. The fetal dose was calculated and the FetDose V5 program was used for risk estimations. Results: The average dose length product (DLP) was 56.17 mGy·cm (range: 51.69 - 59.21 mGy·cm). The average effective dose received by women pregnant was 0.78 mSv. The mean individual fetal dose was 1.5 mGy (range: 0.76 - 1.87 mGy). The risk of Childhood Cancer calculated was: range 1 in 16,000 to 1 in 10,000 and 1 in 260,000 to 1 in 106,000 to the risk of Hereditary Disease, respectively. Conclusion: This study shows that the foetal-maternal doses delivered during CT-Pelvimetry examinations are very low and the risks of childhood cancers and hereditary diseases are derisory, the technology should be further investigated to ensure its full potential for optimal diagnostic accuracy.

Concurrent chemoradiotherapyof different radiation doses and different irradiation fields for locally advanced thoracic esophageal squamous cell carcinoma:A randomized,multicenter,phase Ⅲ clinical trial

Background:Concurrent chemoradiotherapy(CCRT)is the standard treatment for locally advanced esophageal squamous cell carcinoma(ESCC).However,the optimal radiotherapy regimen,particularly in terms of total dose and planned range of irradiation field,remains unclear.This phase III clinical trial aimed to compare the survival benefits between different radiation doses and different target fields.Methods:This trial compared two aspects of radiation treatment,total dose and field,using a two-by-two factorial design.The high-dose(HD)group received 59.4 Gy radiation,and the standard-dose(SD)group received 50.4 Gy.The involved field irradiation(IFI)group and elective nodal irradiation(ENI)group adopted different irradiation ranges.The participants were assigned to one of the four groups(HD+ENI,HD+IFI,SD+ENI and SD+IFI).The primary endpoint was overall survival(OS),and the secondary endpoints included progressionfree survival(PFS).The synergy indexwas used to measure the interaction effect between dose and field.Results:The interaction analysis did not reveal significant synergistic effects between the dose and irradiation field.In comparison to the target field,patients in IFI or ENI showed similar OS(hazard ratio[HR]=0.99,95%CI:0.80-1.23,p=0.930)and PFS(HR=1.02,95%CI:0.82–1.25).TheHDtreatment did not show significantly prolonged OS compared with SD(HR=0.90,95%CI:0.72–1.11,p=0.318),but it suggested improved PFS(25.2 months to 18.0 months).Among the four groups,the HD+IFI group presented the best survival,while the SD+IFI group had the worst prognosis.No significant difference in the occurrence of severe adverse events was found in dose or field comparisons.Conclusions:IFI demonstrated similar treatment efficacy to ENI in CCRT of ESCC.The HD demonstrated improved PFS,but did not significantly improve OS.The dose escalation based on IFI(HD+IFI)showed better therapeutic efficacy than the current recommendation(SD+ENI)and is worth further validation.

0Optimized Fluoroscopy Setting and Appropriate Project Position Can Reduce X-ray Radiation Doses Rates during Electrophysiology Procedures

Background：Nonfluoroscopic three-dimensional electroanatomical system is widely used nowadays,but X-ray remains indispensable for complex electrophysiology procedures.This study aimed to evaluate the value of optimized parameter setting and different projection position to reduce X-ray radiation dose rates.Methods：From June 2013 to October 2013,105 consecutive patients who underwent complex ablation were enrolled in the study.After the ablation,the radiation dose rates were measured by two different settings （default setting and optimized setting） with three projection positions （posteroanterior [PA] projection;left anterior oblique [LAO] 30° projection;and LAO 45° projection）.The parameter of preset voltage,pulse width,critical voltage,peak voltage,noise reduction,edge enhancement,pulse rate,and dose per frame was modified in the optimized setting.Results：The optimized setting reduced radiation dose rates by 87.5％ （1.7 Gy/min vs.13.6 Gy/min,P ＜ 0.001） in PA,87.3％ （2.5 Gy/min vs.19.7 Gy/min,P＜0.001） in LAO 30°,85.9％ （3.1 Gy/min vs.22.1 Gy/min,P ＜ 0.001） in LAO 45°.Increase the angle of projection position will increase the radiation dose rate.Conclusions：We can reduce X-ray radiation dose rates by adjusting the parameter setting of X-ray system.Avoiding oblique projection of large angle is another way to reduce X-ray radiation dose rates.

A multi-provincial survey and analysis of radiation doses from pediatric CT in China

Objective:To survey and analyze the radiation doses of pediatric CT in some provinces(autonomous region)or municipalities in China,and compare them with the data released by the relevant domestic and international organizations,so as to identify the current status of Chinese pediatric CT radiation doses.Methods:Radiation doses of pediatric CT were collected during August and December 2016 from 40 hospitals(including 18 children’s hospitals)in 15 provinces,municipalities or autonomous regions across the China.The procedures of head CT,chest CT and abdomen CT were selected in these hospitals,and 10 patients in each group of 0-<1 y,1-<5 y,5-<10 y and 10-<15 y were collected at random for every procedure.Weighted CT dose index(CTDI_(w)),volumetric CT dose index(CTDI_(vol))and dose length product(DLP)were used as survey quantities.An independent sample Kruskal-Wallis rank sum test was performed for CTDI and DLP for each procedure for different age groups,and pairwise comparisons were performed for intra-group data.The same statistical method was also conducted for CTDI and DLP of the same procedure and age group in different provinces or municipalities.Results:The 75th percentiles of the distribution of CTDI and DLP in different age groups of 0-<1 y,1-<5 y,5-<10 y and 10-<15 y were as follows:36.5,43.4,49.1,51.1 mGy and 488,635,723,852 mGy.cm for head,6.1,6.4,6.8,9.6 mGy and 108,136,187,293 mGy.cm for chest,10.5,10.3,11.4,13.0 mGy and 251,284,353,523 mGy.cm for abdomen.The 50th percentiles of the distribution of the radiation doses for the same procedure varied with the ages(head,CTDI_(w):H=155.66,DLP:H=212.35,P<0.05;chest,CTDI_(vol):H=85.43,DLP:H=197.36,P<0.05;abdomen:H=62.29,DLP:H=173.22,P<0.05)and with lower dose at lower age.Radiation doses were close for head between 5-<10 y and 10-<15 y groups,for chest between 1-<5 y and 5-<10 y groups and between 5-<10 y and 10-<15 y groups,and for abdomen between 0-<1 y and 1-<5 y groups,with no statistically significant difference(the adjusted P>0.05).The dose levels of different provinces or municipalities in the same procedure and age group were not consistent,and the differences were statistically significant(P<0.05).The data were different from the domestic and international values of DRL.The 75th percentiles of CTDI_(w) and DLP values of head CT were close to the data from Japan and UK(United Kingdom),higher than the data from Korea and EC(European Commission).The 75th percentiles of CTDI values of all age groups were lower than the values of Japan and UK,and larger than that of Korea and EC in chest CT and abdomen CT.Conclusions:The 75th percentile values of the distribution of the pediatric CT doses obtained from the survey were inconsistent with those released by the relevant national and international organizations.It is necessary to update the national DRLs for pediatric CT on the basis of the actual survey data.

Effects of Low Dose Radiation on Tumor Apoptosis, Cell Cycle and Apoptosis-Related Protein Bcl-2 in Tumor-Bearing Mice

To study the effects of low dose radiation (LDR) on tumor apoptosis, cellcycle progression and changes of apoptosis-related protein Bcl-2 in tumor-bearing mice. Methods:Male mice of Kunming strain were implanted subcutaneously with S180 sarcoma cells in the left inguenas an in situ experimental animal model. Seven days later, the mice were subjected to 75 mGywhole-body γ-irradiation. At 24 and 48 h after the irradiation, all mice were sacrificed. The tumorsizes were measured, and tumor cell apoptosis and cell cycle progression were analyzed by flowcytometry. The expression of apoptosis-related protein Bcl-2 and the apoptotic rate of tumor cellswere observed by immunohistochemistry and electron microscopy. Results: Tumors grew significantlyslower after LDR (P 【 0.05). The tumor cells were arrested in G1 phrase and the expression of Bcl-2protein decreased at 24 h. Apoptotic rate of tumor cells was increased significantly at 48 h afterLDR (P 【 0.01). Conclusion: LDR could cause a G1-phase arrest and increase the apoptosis of tumorcells through the low level of apoptosis-related protein bcl-2 in the tumor-bearing mice. Theorganized immune function and anti-tumor ability are markedly increased after LDR. Our studyprovides practical evidence of clinical application to cancer treatment.

Application of Low Tube Voltage, Low-concentration Contrast Agent Using a 320-row CT in Coronary CT Angiography: Evaluation of Image Quality, Radiation Dose and Iodine Intake

The effect of low voltage and low concentration contrast agent on image quality of coronary CT angiography,radiation dose and iodine intake was evaluated.A total of 121 patients with body mass index(BMI)<26 kg/m2 and heart rate(HR)<70 beats/min were randomly divided into four groups:group A(n=31,80 kVp,270 mgl/mL);group B(n=33,100 kVp,270 mgl/mL);group C(h=30,100 kVp,320 mgl/mL);group D(w=27,100 kVp,400 mgl/mL).The automatic current modulation system and the iterative algorithm for reconstruction were adopted in each group.The CT values and SD values of the aortic root(AR),subcutaneous fat,left coronary artery opening(LCA),and right coronary artery opening(RCA)were measured in all groups,the signalto-noise ratio(SNR)and contrast noise ratio(CNR)were calculated,and effective radiation dose and iodine intake were recorded.The subjective assessment for image quality was performed by two physicians using a 4-point scale.The results were compared using the one-way ANOVA and rank sum tests.The image quality of the four groups met the clinical diagnostic requirements.The CT values of AR in groups A,B,C,and D were 537.6±71.4,447.2±81.9,445.2±64.9 and 518.5±94.9 Hu,respectively,with no significant difference between group A and group D,or between group B and group C,while CT values in groups B and C were significantly lower than those in groups A and D(P<0.05).In groups A,B,C,and D,the LCA SNR values were 22.7±9.1,23.3±9.1,23.3±7.7 and 26.6±8.9,and the RCA CNR values were 26.9±9.&28.5±11.4,27.7土&8 and 32」±10.6,respectively.The AR visual scores in groups A,B,C and D were 3.8±0.2,3.9±0.3,3.9±0.3 and 4.0±0.3,respectively.There were no significant differences in SNR,CNR and visual score among the four groups(P>0.05).The radiation doses in groups A,B,C and D were 2.6±1.4,3.6±1.&4.9±3.5 and 4.9±2.8 mSv,respectively.The radiation dose in group A was significantly less than that in the rest three groups(P<0.05).The iodine intakes in groups A,B,C and D were 14.9±1.5,15.0±1.5,17.7±2.0 and 18.1±2.5 g,respectively.There was no significant difference in the intake of iodine between groups C and D,or between groups A and B,while iodine intake in groups A and B were significantly reduced as compared with that in groups C and D(P<0.05).It was concluded that for patients with low BMI and controlled HR,compared to 100 kVp tube voltage combined with multiple concentration contrast agents,80 kVp combined with 270 mgl/mL contrast agent is enough to ensure the quality of the images,and can reduce the radiation dose significantly,while reducing the amount of iodine intake notably,thus reducing the incidence of adverse reaction.

Correlation between Low Tube Voltage in Dual Source CT Coronary Artery Imaging with Image Quality and Radiation Dose

The influence of low tube voltage in dual source CT（DSCT） coronary artery imaging on image quality and radiation dose and its application value in clinical practice were investigated. Totally, 300 cases of chest pain with low body mass index（BMI 〈18.5 kg/m2） subjected to DSCT coronary artery imaging were prospectively enrolled. The heart rate in all patients were greater than 65/min. The retrospective ECG gated scanning mode and simple random sampling method were used to assign the patients into groups A, B and C（n=100 each）. The patients in groups A, B and C experienced 120-, 100-, and 80-kV tube voltage imaging respectively, and the image quality was evaluated. The CT volume dose index（CTDIvol） and dose length product（DLP） were recorded, and the effective dose（ED） was calculated in each group. The image quality scores and radiation doses in groups were compared, and the influence of tube voltage on image quality and radiation dose was analyzed. The results showed that the excellent rate of image quality in groups A, B and C was 95.69%, 94.72% and 96.33% respectively with the difference being not statistically significant among the three groups（P〉0.05）. The CTDIvol values in groups A, B and C were 51.35±12.21, 21.28±7.13 and 6.34±3.34 mGy, respectively, with the difference being statistically significant（P〈0.05）. The ED values in groups A, B and C were 9.27±1.63, 4.56±2.29 and 2.29±1.69 mSv, respectively, with the difference being statistically significant（P〈0.05）. It was suggested that for the patients with low BMI, the application of DSCT coronary artery imaging with low tube voltage can obtain satisfactory image quality, and simultaneously, significantly reduce the radiation dose.

Involvement of Endoplasmic Reticulum Stress in Apoptosis of Testicular Cells Induced by Low-dose Radiation

Summary： The study examined the role of endoplasmic reticulum stress （ERS） and signaling pathways of inositol-requiring enzyme-1 （IRE1）, RNA-activated protein kinase-like ER kinase （PERK） and activating transcription factor-6 （ATF6） in apoptosis of mouse testicular cells treated with low-dose radiation （LDR）. In the dose-dependent experiment, the mice were treated with whole-body X-ray irradiation at different doses （25, 50, 75, 100 or 200 mGy） and sacrificed 12 h later. In the time-dependent experiment, the mice were exposed to 75 mGy X-ray irradiation and killed at different time points （3, 6, 12, 18 or 24 h）. Testicular cells were harvested for experiments. H202 and NO concentrations, and Ca2＋-ATPase activity were detected by biochemical assays, the calcium ion concentration （[Ca2＋]i） by flow cytometry using fluo-3 probe, and GRP78 mRNA and protein expressions by quantitative real-time RT-PCR （qRT-PCR） and Western blotting, respectively. The mRNA expressions of S-XBP1, JNK, caspase-12 and CHOP were measured by qRT-PCR, and the protein expressions of IREla, S-XBP1, p-PERK, p-elF2a, ATF6 p50, p-JNK, pro-caspase-12, cleaved caspase-12 and CHOP by Western blot- ting. The results showed that the concentrations of H202 and NO, the mR_NA expressions of GRP78, S-XBP1, JNK, caspase-12 and CHOP, and the protein expressions of GRP78, S-XBP1, IREla, p-PERK, p-elF2a, ATF6 p50, p-JNK, pro-caspase-12, cleaved caspase-12 and CHOP were significantly increased in a time- and dose-dependent manner after LDR. But the [Ca2]i and Ca2-ATPase activities were sig nificantly decreased in a time and dose-dependent manner. It was concluded that the ERS, regulated by IRE 1, PERK and ATF6 pathways, is involved in the apoptosis of testicular cells in LDR mice, which is associated with ERS-apoptotic signaling molecules of JNK, caspase-12 and CHOP.

Diurnal Variations in Solar Ultraviolet Radiation at Typical Anatomical Sites

Objective Solar ultraviolet （UV） radiation is an important environmental factor that affects human health. The understanding of diurnal variations of UV radiation at anatomical sites may be helpful in developing ways to protect humans from the harmful effects of UV radiation. Methods In order to characterize the diurnal variations, the UV exposure values were measured at 30 min intervals by using Solar-UV Sensors and a rotating manikin in Shenyang city of China （41°51＇N, 123°27%）. Measurement data for four representative days （in each of the four seasons respectively） were analyzed. Results The diurnal variations in solar UV radiation at the shoulder, the forehead and the chest were similar to those associated with a horizontal control measurement. However, the diurnal variations at the eye and the cheek exhibited bimodal distributions with two peaks in spring, summer and autumn, and a unimodal distribution in winter. The UV exposure peaks at the eye and the cheek were measured at solar elevation angles （SEA） of about 30° and 40°, respectively. Conclusion The protection of some anatomical sites such as the eye from high UV exposure should not be focused solely on the periods before and after noon, especially in the places and seasons with high SEA.

INVOLVEMENT OF THE Ca^(2+) PROTEIN KINASE C AND ADENYLATE CYCLACE SIGNAL PATHWAYS IN THE ACTIVATION OF THYMOCYTES IN RESPONSE TO WHOLE BODY IRRADIATION WITH LOW DOSE X RAYS

WT5”BZ] To study the molecular mechanism of the stimulatory effect of low dose radiation(LDR) on T cell activation. [WT5”BX]Methods.[WT5”BZ] Thymocytes from Kunming mice exposed to whole body irradiation(WBI) with different doses of X rays were analyzed for the changes in signal molecules of the phospholipase C phosphatidylinositol biphosphate(PLC IP2) and G protein adenylate cyclase(AC) pathways. [WT5”BX]Results.[WT5”BZ]It was found that[Ca 2+ ] i increased in response to doses within 0 2 Gy which was most marked after 0 075 Gy and the increase was accentuated in the presence of Con A. The changes in CD3 and calcineurin(CN) expression of the thymocytes followed the same pattern as the alterations in [Ca 2+ ] i after LDR. The expression of α,β1 and β2 isoforms of protein kinase C(PKC) was all up regulated after 0 075 Gy with the increase in PKC β1 expression being most marked. The cAMP/cGMP ratio and PKA activity of the thymocytes was lowered after low dose radiation and increased after doses above 0 5 Gy in a dose dependent manner, thus giving rise to J shaped dose response curves. The Ca antagonist TMB 8 and cAMP stimulant cholera toxin suppressed the augmented thymocyte proliferation induced by LDR. [WT5”BX]Conclusion.[WT5”BZ]Data presented in the present paper suggest that activation of the PLC PIP2 signal pathway and suppression of the AC cAMP signal pathway are involved in the stimulation of the thymocytes following WBI with low dose X rays.

Increased Levels of p53 and PARP-1 in EL-4 Cells Probably Related with the Immune Adaptive Response Induced by Low Dose Ionizing Radiation in vitro

Objective This paper is to explore the DNA repair mechanism of immune adaptive response （AR） induced by low dose radiation （LDR）, the changes of mRNA levels and protein expressions of p53, ATM, DNA-PK catalytic subunit （DNA-PKcs） and PARP-1 genes in the LDR-induced AR in EL-4 cells. Methods The apoptosis and cell cycle progression of EL-4 cells were detected by flow cytometry in 12 h after the cells received the pre-exposure of 0.075 Gy X-rays （inductive dose, D 1） and the succeeding high dose irradiation （challenge dose, D2; 1.0, 1.5, and 2.0 Gy X-rays, respectively） with or without wortmannin （inhibitor of ATM and DNA-PK） and 3-aminobenzamid （inhibitor of PARP-1）. And the protein expressions and mRNA levels related to these genes were detected with flow cytometry and reverse transcription-polymerase chain reaction in 12 h after irradiation with D2. Results The mRNA and protein expressions of p53 and PARP-1 in EL-4 cells in the D1 ＋ D2 groups were much lower than those in the D2 groups, and those of PARP-1 in the 3-AB ＋ D2 and the 3-AB ＋ D1 ＋ D2 groups were much lower than those in the D2 and the D1 ＋ D2 groups. The percentage of apoptotic EL-4 cells in the 3-AB ＋ D1 ＋ D2 groups was much higher than that in the D1 ＋ D2 groups, that in the G0/G1 and the G2 ＋ M phases was much higher, and that in the S phase were much lower. Although the ATM and DNA-PKcs mRNA and protein expressions in wortmannin ＋ D1 ＋ D2 groups were much lower than those in the D1 ＋ D2 groups, there were no significant changes in the apoptosis and cell cycle progression between the wortmannin ＋ D1 ＋ D2 and the D1 ＋ D2 groups. Conclusion PARP-1 and p53 might play important roles in AR induced by LDR.

Radiation dose measurements in coronary CT angiography

Coronary computed tomography(CT)angiography has been recognized as the most rapidly developed imaging technique in the diagnosis of coronary artery disease due to the emergence and technological advances in multislice CT scanners.Coronary CT angiography has been confirmed to demonstrate high diagnostic and predictive value in coronary artery disease when compared to invasive coronary angiography.However,it suffers from high radiation dose which raises concerns in the medical field.Various dose-reduction strategies have been proposed with effective outcomes having been achieved to reduce radiation exposure to patients.This article provides an introduction and overview of the series of articles that will focus on each particular topic related to coronary CT angiography.

Truncus arteriosus:Diagnosis with dual-source computed tomography angiography and low radiation dose

Truncus arteriosus is an uncommon congenital cardiac abnormality which is characterized by a single arterial trunk origin from the heart that supplies both the systemic,pulmonary and coronary circulation.We present a preterm newborn female patient with type 2 truncusarteriosus,left superior vena cava and aberrant subclavian artery diagnosed with low dose dual-source cardiac computed tomography(CT).We discuss that low dose dual-source cardiac CT has more advantages than other imaging methods and it is an important modality for assessment of patients with conotruncal anomalies such as truncusarteriosus.

Effect of Cycloheximide on the Adaptive Response Induced by Low Dose Radiation

Human lymphocytes pre-exposed to 10 mGy or 50 mGy of X-rays become less sensitive to subsequent large dose irradiation, exhibited lower rate of chromosome aberration than expected. This adaptive response could be inhibited by cycloheximide, a protein synthesis inhibitor for successive 2 h period ranging from 0.5h before to 4h after the low dose exposure, indicating that the adaptive response was directly related with the protein synthesis.

Effect of Low Dose Radiation on Intracellular Calcium and Protein Kinase C in Lymphocytes

It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming micc With 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+], mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBl with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed

Total dose radiation response of modified commercial silicon-on-insulator materials with nitrogen implanted buried oxide

Nitrogen ions of various doses are implanted into the buried oxide （BOX） of commercial silicon-on-insulator （SOI） materials, and subsequent annealings are carried out at various temperatures. The total dose radiation responses of the nitrogen-implanted SOI wafers are characterized by the high frequency capacitance-voltage （C-V） technique after irradi- ation using a Co-60 source. It is found that there exist relatively complex relationships between the radiation hardness of the nitrogen implanted BOX and the nitrogen implantation dose at different irradiation doses. The experimental results also suggest that a lower dose nitrogen implantation and a higher post-implantation annealing temperature are suitable for improving the radiation hardness of SOI wafer. Based on the measured C V data, secondary ion mass spectrometry （SIMS）, and Fourier transform infrared （FTIR） spectroscopy, the total dose responses of the nitrogen-implanted SOI wafers are discussed.

Modulation of MMP-2 and TIMP-2 by low dose radiation in mice bearing S180 sarcoma

Objective To investigate the inhibition of low dose radiation （LDR） on S180 sarcomas and its modulation of MMP-2 and TIMP-2 in mice. Methods $180 subcutaneously implanted tumor model mice were randomly divided into two groups： control （N） and low dose radiation （LDR） groups. N mice were sacrificed after 12 h, whereas LDR mice were sacrificed after 12 （LDR-12 h）, 24 （LDR-24 h）, 48 （LDR-48 h）, and 72 （LDR-72 h） h. Thereafter, we measured the tumor volumes. Histopathology was performed, and P-V immunohistochemistry was applied to assess MMP-2 and TIMP-2 expression. Results Compared with the control group, the tumor growth was significantly inhibited in the LDR groups （P 〈 0.05）. MMP-2 expression was considerably reduced in LDR-24h （P 〈 0.05） and LDR-48h （P 〈 0.05）, whereas the change of TIMP-2 was not obvious in the LDR groups （P 〉 0.05） in contrast to that of the control group. Conclusion LDR can effectively suppress the growth of S180 implanted tumors by reducing MMP-2, which is associated with invasion and metastasis.

An evaluation of the influence of impurity concentration and composition in concrete on activation and radiation dose in the reactor facility

The content analysis of radioactive waste and radiation dose evaluation is considered as one of the important factors in the reactor facility design.This kind of buildings consists of the concrete for the most part and uses it as the structure and shield of the building.Generally,the concrete has impurities such as cobalt,europium,nickel,and cesium with specific content depending on the production method or manufacturing company.Dominant radioactive nuclides generated from the fundamental components of concrete are considered that it is less contributed to the radiation dose because they are beta decay nuclides in general.Thus,impurities of irradiated concrete in the reactor facilities,are considered occasionally an important evaluation factor for induced activity.In this study,the influence on the activation of impurities in concrete was evaluated from the radiation dose and induced activity calculations.The calculation was evaluated at the bio-shield which is one of the areas with the highest neutron irradiation among the concrete structure in the reactor facility.The results show that radioactive nuclides with gamma decay were produced in these impurities.Moreover,the radiation dose of concrete with impurities was higher than concrete without impurities.The increased radiation dose was quantified through the content of impurities.

EFFECT OF IRRADIATION TEMPERATURE ON GENERAL EQUATION OF SOL FRACTION-DOSE RELATIONSHIP FOR FLUOROPOLYMERS

In this paper, the effect of irradiation temperature on sol fraction-dose relationship of tluoropolymers was studied. It was found that the increasing of irradiation temperature can result in the decreasing of β value of fluoropolymer, which increases the crosslinking probability of fluoropolymer. The relationship between crosslinking parameter β and irradiation temperature (T_i)of fluoropolymer is established as follows:β=2.2×10^(-3) T_g+4×10^(-4)(T_g-T_i)+0.206.values of some tluoropolymers calculated from the above expression are in agreement with the experimental values.