Life Time Attributable Cancer Risk Estimated Using Scanner Reported Dose Length Product during Chest Computed Tomography Imaging in Young Children

This study aims to estimate the lifetime attributable cancer risk (LAR) for pediatric chest computed tomography (CT) examinations in five age groups using recently published age and region-specific conversion coefficients multiplying the widely available scanner registered dose length products (DLP) displayed on the CT console and hence calculating the Effective Dose (ED). The ED is then multiplied by the International Commission on Radiological Protection (ICRP) published risk factor for LAR. The obtained LAR values are compared with the international literature. Factors that may affect the LAR value are reported and discussed. The study included one hundred twenty five chest CT examinations for both males and females aged from less than one year to fifteen years. The patients reported data are from one single medical institution and using two CT scanners from June 2022 to December 2023. The results of this study may serve as benchmark for institutional radiation dose reference levels and risk estimation.

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.

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.

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.

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.

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

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.

Assessing radiation dose for postoperative radiotherapy in prostate cancer: Real world data

BACKGROUND Approximately 30%of patients with localized prostate cancer(PCa)who undergo radical prostatectomy will develop biochemical recurrence.In these patients,the only potentially curative treatment is postoperative radiotherapy(PORT)with or without hormone therapy.However,the optimal radiotherapy dose is unknown due to the limited data available.AIM To determine whether the postoperative radiotherapy dose influences biochemical failure-free survival(BFFS)in patients with PCa.METHODS Retrospective analysis of patients who underwent radical prostatectomy for PCa followed by PORT-either adjuvant radiotherapy(ART)or salvage radiotherapy(SRT)-between April 2002 and July 2015.From 2002 to 2010,the prescribed radiation dose to the surgical bed was 66-70 Gy in fractions of 2 Gy;from 2010 until July 2015,the prescribed dose was 70-72 Gy.Patients were grouped into three categories according to the total dose administered:66-68 Gy,70 Gy,and 72 Gy.The primary endpoint was BFFS,defined as the post-radiotherapy prostatespecific antigen(PSA)nadir+0.2 ng/mL.Secondary endpoints were overall survival(OS),cancer-specific survival(CSS),and metastasis-free survival(MFS;based on conventional imaging tests).Treatment-related genitourinary(GU)and gastrointestinal(GI)toxicity was evaluated according to Radiation Therapy Oncology Group/European Organization for Research and Treatment of Cancer criteria.Finally,we aimed to identify potential prognostic factors.BFFS,OS,CSS,and MFS were calculated with the Kaplan-Meier method and the log-rank test.Univariate and multivariate Cox regression models were performed to explore between-group differences in survival outcome measures.RESULTS A total of 301 consecutive patients were included.Of these,93(33.6%)received ART and 186(66.4%)SRT;22 patients were excluded due to residual macroscopic disease or local recurrence in the surgical bed.In this subgroup(n=93),43 patients(46.2%)were Gleason score(GS)≤6,44(47.3%)GS 7,and 6(6.5%)GS≥8;clinical stage was cT1 in 51(54.8%),cT2 in 35(39.3%),and cT3 in one patient(1.1%);PSA was<10 ng/mL in 58(63%)patients,10-20 ng/mL in 28(30.6%),and≥20 ng/mL in 6(6.4%)patients.No differences were found in BFFS in this patient subset versus the entire cohort of patients(P=0.66).At a median follow-up of 113 months(range,4-233),5-and 10-year BFFS rates were 78.8%and 73.7%,respectively,with OS rates of 93.3%and 81.4%.The 5-year BFFS rates in three groups were as follows:69.6%(66-68 Gy),80.5%(70 Gy)and 82.6%(72 Gy)(P=0.12):the corresponding 10-year rates were 63.9%,72.9%,and 82.6%(P=0.12),respectively.No significant between-group differences were observed in MFS,CSS,or OS.On the univariate analysis,the following variables were significantly associated with BFFS:PSA at diagnosis;clinical stage(cT1 vs cT2);GS at diagnosis;treatment indication(ART vs SRT);pre-RT PSA levels;and RT dose 66-68 Gy vs.72 Gy(HR:2.05;95%CI:1.02-4.02,P=0.04).On the multivariate analysis,the following variables remained significant:biopsy GS(HR:2.85;95%CI:1.83-4.43,P<0.001);clinical stage(HR:2.31;95%CI:1.47-4.43,P=0.01);and treatment indication(HR:4.11;95%CI:2.06-8.17,P<0.001).Acute grade(G)1 GU toxicity was observed in 11(20.4%),17(19.8%),and 3(8.3%)patients in each group(66-68 Gy,70 Gy and 72 Gy),respectively(P=0.295).Acute G2 toxicity was observed in 2(3.7%),4(4.7%)and 2(5.6%)patients,respectively(P=0.949).Acute G1 GI toxicity was observed in 16(29.6%),23(26.7%)and 2(5.6%)patients in each group,respectively(P=0.011).Acute G2 GI toxicity was observed in 2(3.7%),6(6.9%)and 1(2.8%)patients,respectively(P=0.278).No cases of acute G3 GI toxicity were observed.CONCLUSION The findings of this retrospective study suggest that postoperative radiotherapy dose intensification in PCa is not superior to conventional radiotherapy treatment.

NK ACTIVITY OF LYMPHOCYTE SUBSETS AND THE EFFECTS OF LOW DOSE RADIATION

This work was supported by the National Natural Science Foundation of China (No. 3870902). Objective: To determine the NK activity of lymphocyte subsets and the effects of low dose radiation. Methods: Lymphocyte subsets were separated by monoclonal antibodies. The NK activity of each subset on tumor cells was detected by radioactive release method. Results: The results showed that besides NK cells, CD 4, CD 8 and B cells alone can kill tumor cells. But the cellkilling activity of NK cells appeared to be strongest. There was synergistic effect between CD 4 and NK cells. The activity of mixed lymphocytes was more than that of only one subset. The effect of low dose radiation (LDR) on NK activity of panlymphocytes or NK cells was different. Conclusion: This paper demonstrated that NK activity of mononuclear cells was called “NK activity of lymphocytes”, but it is not true. Only when NK cells were separated by monoclonal antibodies, its killer activity can be called “activity of NK cells”.

Computed Tomography Protocol Optimisation for Pediatric Head Trauma: Radiation Dose and Image Quality Assessment

Purpose: Children are sometimes examined with Computed Tomography protocols designed for adults, leading to radiation doses higher than necessary. Lack of optimisation could lead to image quality higher than what is needed for diagnostic purposes with associated high doses to patients. Optimising the protocols for paediatric head trauma CT imaging will reduce radiation dose. Objective: The study aimed to optimise radiation dose and assess the image quality for a set of protocols by evaluating noise, a contrast to noise ratio, modulation transfer function and noise power spectrum. Methods: Somaton Sensation 64 was used to scan the head of an anthropomorphic phantom with a set of protocols. ImageJ software was used to analyse the paediatric head image from the scanner. IMPACTSCAN dosimeter software was used to evaluate the radiation dose to the various organs in the head. MATLAB was used to analyse the Modulation Transfer Function and the Noise Power. Results: The estimated Computed Tomography Dose Index volume (CTDIvol) increased with increasing tube current and tube voltage. The high pitch of 0.9 gave a lower dose than the 0.5 pitch. The eye lens received the highest radiation dose (39.2 mGy) whiles the thyroid received the least radiation dose (13.7 mGy). There was an increase in noise (62.46) when the H60 kernel was used and a lower noise (8.829) was noticed when the H30 kernel was used. Conclusion: The results obtained show that the H30 kernel (smooth kernel) gave higher values for noise and contrast to noise ratio (CNR) than the H60 kernel (sharp kernel). The H60 kernel produced high values for the modulation transfer function (MTF) and noise power spectrum (NPS). The eye lens received the highest radiation dose.

Total Ionizing Dose Radiation Effects in the P-Type Polycrystalline Silicon Thin Film Transistors

The total ionizing dose radiation effects in the polycrystalline silicon thin film transistors are studied. Transfer characteristics, high-frequency capacitance-voltage curves and low-frequency noises (LFN) are measured before and after radiation. The experimental results show that threshold voltage and hole-field-effect mobility decrease, while sub-threshold swing and low-frequency noise increase with the increase of the total dose. The contributions of radiation induced interface states and oxide trapped charges to the shift of threshold voltage are also estimated. Furthermore, spatial distributions of oxide trapped charges before and after radiation are extracted based on the LFN measurements.

Evaluation of Radiation Exposure Literacy among Mammography Examinees Using Radiation Dose Distribution in Mammography Examinations

Introduction: Radiation is indispensable for diagnosis and treatment and is widely used in medicine. This study aimed to determine patients’ knowledge and ability to understand radiation exposure to assess the usefulness of providing information on radiation doses to examinees. Material and Methods: The radiation exposure literacy of mammography examinees was assessed using a new scale consisting of the following five items: “collection of information from various sources”, “selection of information necessary for oneself”, “understanding and communication of information”, “judgment of the reliability of information”, and “ability to plan and act based on information”. We analyzed the relationship of these items with examinees’ attributes and clarified the level of understanding of radiation exposure dose associated with mammography examinations by providing examinees with visual information in the form of color maps. Results: The relationship between “information collection” and several attributes of radiation exposure literacy was strong. In addition, providing visual information on radiation doses using dose distribution maps in mammography examinations could deepen the understanding of radiation doses among examinees. Conclusion: By understanding the radiation exposure literacy of examinees and comparing it with their attributes, it is possible to provide suggestions for developing methods of providing radiation dose information tailored to individual examinees. In addition, improving radiation exposure literacy will enable the development of skills necessary to provide safe medical care to medical examinees.

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.

Combination therapy using low dose radiation,plasma exchange,and a robust antiviral may induce synergic beneficial interactions for mitigating severe COVID‐19

Recent studies confirm that current antiviral drugs are not fully effective on coronaviruses.Our research team introduced the idea of radiotherapy at low doses for coronavirus disease 2019(COVID-19)in March 2020.This issue later received much attention from many scientists around the world.Low dose radiation therapy exerts modulatory effects in acute inflammation,potentiate the anti-viral immune responses,and can be localized to the organ affected by inflammatory reactions,such as lungs.The findings of the first clinical trial show that low dose radiation therapy is safe,and reveal early promise of efficacy.Moreover,plasma exchange therapy may be a rescue therapy in severe COVID-19 patients,as it can quickly eliminate the cytokines and chemokines from the circulation.Remdesivir was introduced as an anti-virus agent that prevents viral RNA synthesis and coronavirus replication and reduces the viral load.If antiviral therapy is poor,the virus has ample opportunity to mutate and increase its fitness through adaptive mutations.Given this consideration,instead a single treatment,we preferentially recommend a combination therapy using low dose radiation therapy plasma exchange and a robust antiviral agent(not yet available).This review provides a viewpoint concerning the potential synergistic effects of low dose radiation therapy,plasma exchange therapy and robust antiviral agent in severe acute respiratory syndrome coronavirus type 2(SARS-CoV-2)-infected patients as a more effective strategy for possible treatment of severe COVID-19 patients.

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.

Value of low-dose and optimized-length computed tomography(CT)scan in CT-guided percutaneous transthoracic needle biopsy of pulmonary nodules

Objective:To investigate the value of application of low-dose and optimized length CT scan on puncture results,complications and patients’radiation dosage during CT-guided percutaneous biopsy of pulmonary nodules(PTNB).Methods:A total of 231 patients with PTNB under CT guidance were collected.Low dose scanning utilized tube current of 20 mA as compared with 40 mA in conventional dosage.Optimized length in CT is defined as intentionally narrowing the range of CT scanning just to cover 25 mm(5 layers)around the target layer during needle adjustment.According to whether low-dose scans and optimized length scans techniques were utilized,patients were divided into three groups:conventional group(conventional sequence+no optimization),optimized length group(conventional sequence+optimized length),and low-dose optimized length group(low dose sequence+optimized length).The ED(effective dose),the DLP(dose length product),the average CTDIvol(Volume CT dose index),total milliampere second between subgroups were compared.Results:Compared with the conventional group,ED,intraoperative guidance DLP,total milliseconds and operation time in the optimized length group were reduced by 18.2%(P=0.01),37%(P=0.003),17.5%(P=0.013)and13.3%(P=0.021)respectively.Compared with the optimized length group,the ED was reduced by 87%,preoperative positioning,intraoperative guidance and postoperative review DLP were also reduced by 88%,total milliampere second was reduced by 79%,with an average CTDIvol was reduced by 86%,in the low-dose optimized length group(P<0.001 for all).Conclusion:Optimizing the length during CT scanning can effectively reduce the intraoperative radiation dose and reduce the operation time compared with conventional plan;low-dose and optimized length CT scan can further reduce the total radiation dose compared with optimized length group with no differences on intraoperative complications,biopsy results and operation time.