Purpose To investigate the dosimetric differences among RapidArc (RA) plans which were designed on different target volumes in hepatocellular carcinoma (HCC).Methods A total of 10 HCC patients underwent 3D-CT scan under free breathing ( FB),end inspiration hold ( EIH ) associated with active breath coordinator (ABC) and 4D-CT scan.The 4D-CT were sorted into 10 sets of CT images according to respiratory cycle.The gross tumor volume (GTV) was manually contoured on different CT images.The individual internal gross target volume ( IGTV1 ) was obtained from 4D-CT,and the individual margins from GTVFB to IGTV1.IGTV2 were obtained from GTVFB using individual margins.The planned target volumes (PTV-1,PTV-2,PTV-3 and PTV-4 ) were obtained from GTVFB,IGTV1,IGTV2 and GTVEIA applying different margins.The RA plans (RA1,RA2,RA3 and RA4 ) were designed from different PTVs,and for RA1,RA2 and RA3 the simple 358° arc were used,while three 135° arcs were used for RA4.The dosimetric differences were compared.Results The PTV-1 and PTV-3 were larger than PTV-2 and PTV-4; the mean values of PtV-1/PTV-2 and PTV-1/PTV-4 were 2.5 and 1.9,respectively.There were no significant differences in conformal index,homogeneity index,maximum dose,and minimum dose of PTV among 4 RA plans.The irradiation dose of normal liver of RA3 and RA4 were 8.23 Gy and 7.63 Gy respectively,both significantly lower than those of RA1 and RA2 (10.21 Gy,9.62 Gy,x2 =10.68,P ＜0.05 ),and the V30of RA3 and RA4 were 5.24％ and 5.05％ respectively,both significantly lower than those of RA1 and RA2 (7.76％,6.12％,x2 =14.76,P ＜ 0.05 ).There were no significant differences in irradiation doses of stomach and duodenum among different plans.Conclusions Using 4D-CT or ABC technology with RapidArc in HCC can define the target volume accurately and achieve prefect dose distribution sparing more normal liver volume,compared to the traditional margins.4D-CT and ABC play similar roles in sparing normal liver.

Objective To study the cumulative radiation dose of multiple trauma patients during their hospitalization and to analyze the dose influece factors.Methods The DLP for CT and DR were retrospectively collected from the patients during June,2009 and April,2011 at a university affiliated hospital.The cumulative radiation doses were calculated by summing typical effective doses of the anatomic regions scanned.Results The cumulative radiation doses of 113 patients were collected.The maximum,minimum and the mean values of cumulative effective doses were 153.3,16.48 mSv and(52.3 ± 26.6) mSv.Conclusions Multiple trauma patients have high cumulative radiation exposure.Therefore,the management of cumulative radiation doses should be enhanced.To establish the individualized radiation exposure archives will be helpful for the clinicians and technicians to make decision wheather to image again and how to select the imaging parameters.

Objective To introduce and evaluate the characteristics of a GyroKnife Digital Cobalt-60 System for stereotactic radiotherapy and radiosurgery in mechanical aspect.Methods To test the radiation safety,the dose rate required for radiation protection was measured by using an ionization survey meter ( Inovision Model 451 B,Cleveland,OH ).Micrometer was used to verify the accuracy of the table in movement and protractor to verify the rotation movement range.The 160 mm diameter polystyrene spherical phantom and film were used in measurement of the radiation Full Width at Half Maximum.And the difference between radiation isocenter and mechanical isocenter was also verified.Results Clinical requirement in radiation protection was met.The maximum error of table movement accuracy was 0.2 cm at Z axis; the maximum error of gantry movement accuracy was 0.1°.For all the collimators,radiation Full Width at Half Maximum ( FWHM ) was 2.55,5.40,10.50,and 18.55 mm and average penumbra was 5.0,12.4,30.1,and 51.5 mm,respectively.The maximum difference between mechanical center and radiation center was 1.41 mm.Conclusions Stereotactic radiotherapy and radiosurgery has good mechanical characteristics and is suitable clinic applications.

Objective To investigate the dosimetric performance of COMPASS system,a novel 3D quality assurance system for the verification of nasopharyngeal carcinoma volumetric modulated therapy (VMAT) treatment plan.Methods Eight VMAT treatment plans of nasopharyngeal carcinoma patients were performed with MasterPlan,a treatment planning system (TPS),and then these treatment plans were sent to the COMPASS and MOSAIQ system,a coherent control system,respectively.Comparison of the COMPASS reconstructed dose versus TPS dose was conducted by using the dose volume-based indices:dose received by 95％ volume of target ( D95％ ),mean dose ( Dmean ) and γ pass rate,dose to the 1％ of the spinal cord and brain stem volume ( D1％ ),mean dose of leaf and right parotid ( Dmean ),and the volume received 30 Gy for left and right parotid (V30).COMPASS can reconstruct dose with the real measured delivery fluence after detector commissioning.Results The average dose difference for the target volumes was within 1％,the difference for D95 was within 3％ for most treatment plans,and the γ pass rate was higher than 95％ for all target volumes.The average differences for the D1％ values of spinal cord and brain stem were ( 4.3 ± 3.0) ％ and ( 5.9± 2.9 ) ％ respectively,and the average differences for the Dmean values of spinal cord and brain stem were ( 5.3 ± 3.0 ) ％ and ( 8.0 ± 3.5 ) ％ respectively.In general the COMPASS measured doses were all smaller than the TPS calculated doses for these two organs.The average differences of the Dmean values of the left and right parotids were( 6.1± 3.1 ) ％ and ( 4.7 ± 4.4 ) ％ respectively,and the average differences of the V30 values of the left and right parotids were (9.4 ± 7.5 ) ％ and (9.4 ± 9.9)％ respectively.Conclusions An ideal tool for the VMAT verification,the patient anatomy based COMPASS 3D dose verification system can check the dose difference between the real delivery and TPS calculation directly for each individual organ,either target volumes or critical organs.

Objective To study the relationship between parameter settings in the intensity-modulated radiation therapy (IMRT) planning in order to explore the effect of parameters on absolute dose verification.Methods Forty-three esophageal carcinoma cases were optimized with Pinnacle 7.6c by experienced physicist using appropriate optimization parameters and dose constraints with a number of iterations to meet the clinical acceptance criteria.The plans were copied to water-phantem,0.13 cc ion Farmer chamber and DOSE1 dosimeter was used to measure the absolute dose.The statistical data of the parameters of beams for the 43 cases were collected,and the relationships among them were analyzed.The statistical data of the dosimetry error were collected,and comparative analysis was made for the relation between the parameters of beams and ion chamber absolute dose verification results.Results The parameters of beams were correlated among each other.Obvious affiliation existed between the dose accuracy and parameter settings.When the beam segment number of IMRT plan was more than 80,the dose deviation would be greater than 3％ ; however,if the beam segment number was less than 80,the dose deviation was smaller than 3％.When the beam segment number was more than 100,part of the dose deviation of this plan was greater than 4％.On the contrary,if the beam segment number was less than 100,the dose deviation was smaller than 4％ definitely.Conclusions In order to decrease the absolute dose verification error,less beam angles and less beam segments are needed and the beam segment number should be controlled within the range of 80.

Objective To determine the levels of radiation-induced expressions of HIF-1α and Survivin in three human lymphoma cell lines with or without HIF-1a specific antagonist or HIF-1a siRNA transfection and to explore the possible mechanism of cell radioresistance.Methods Namalwa,Ramos,Raji cells were irradiated with X-rays with or without the combination of echinomycin (EC),a HIF-1α specific inhibitor,or transfection of HIF-1α siRNA.Then the expression levels of HIF-1α and Survivin proteins and mRNAs were determined by Western blot and real-time PCR,respectively.Results After irradiation,the expression level of HIF-1α protein was up-regulated at 10-20 h followed by up-regulation of survivin protein at 24 h (t =7.53-31.31,P ＜ 0.01 ) in three lymphoma cell lines.Radiation-induced up-expression of survivin protein was significantly reduced by either HIF-1α inhibition or EC treatment (t =7.21-32.81,P ＜0.01 ).However,radiation failed to induce up-erpression of survivin at both mRNA and protein levels after transfection with HIF-1α siRNA.Conclusion HIF-1α-Survivin pathway is activated in human lymphoma cells after radiation,which might be involved in the cell radioresistance.

Objective To investigate the relationship between the effect of unmethylated cytosine phosphate-guanine oligodeoxynucleotide ( CpG ODN ) 7909 on X-ray-induced G2/M phase arrest and apoptosis and the phosphorylation of ATM kinase.Methods Human lung adenocarcinoma A549 cells were randomly classified into five groups,control,CpG group,irradiation group,CpG + irradiation group and ATM siRNA + CpG + irradiation group.Cell survival fraction was evaluated by clonogenic assay.Cell cycle and apoptosis were analyzed by flow cytometry.The expressions of ATM,checkpoint kinase-2(Chk2) and p53 were detected with Western blot.Results Compared to the situation under X-ray irradiation alone,decreased cell clonogenic survival,prolonged G2/M arrest,and increased cell apoptosis were observed after the combination treatment with CpG ODN7909 and X-rays ( t =13.41,17.32 and 7.71,P ＜ 0.05).Moreover,the phosphorylations on ATM,Chk2,and p53 were increased in the irradiated A549 cells that had been pre-treated with CpG ODN7909.After ATM siRNA interfering,abrogation of G2/M arrest,reduction of apoptosis,and decrease of Chk2 and p53 phosphorylation were found in A549 cells treated with CpG ODN7909 and X-rays ( t =26.84,2.98,47.24 and 67.47,P ＜0.05).Conclusions CpG ODN7909 can enhance the X-ray-induced phosphorylation of ATM kinase in human lung adenocarcinoma cells in vitro,which might be involved in regulating G2/M phase arrest and apoptosis.

Objective To explore the combination effect of unmethylated cytosine-phosphate-guanine oligodeoxynucleotide (CpG ODN) 1826 and X-rays on Lewis lung cancer in mouse and the dose response of CpG ODN.Methods The tumor-bearing mouse model was established by injecting Lewis lung cancer cells into the right infra-axillary dermis of mouse.Sixty-four C57BL /6 J mice were evenly randomized into eight groups with 8 mice each:control group,IR group,CpG OND1826 0.15 mg group,CpG OND1826 0.3 mg group,CpG OND1826 0.45 mg group,CpG OND1826 0.15 mg + IR group,CpG OND1826 0.30 mg+ IR group,and CpG OND1826 0.45 mg + IR group.On the 1st,2nd,and 9th days,CpG ODN was injected into mouse.After 3 hours of injection,the mice were start to irradiate with X-rays once a day on the 2nd-6th days,and the total dose was 12.50 Gy.Tumor growth and TGD were measured,and the apoptosis of tumor cells were examined with TUNEL.Results The Lewis lung cancer-bearing model was successfully established in all mice.Under the treatments of CpG OND1826 and irradiation,the tumor volumes were smaller than that of control group,and the tumor volumes of CpG OND1826 0.45 mg+IR group was the smallest.TUNEL results revealed that the apoptosis rate were (2.40 ± 0.51 )％ in control group,(5.62 ±0.50)％ in IR,(7.13±0.83)％ in CpG OND1826 0.15 mg,(11.63±1.06)％ in CpG OND1826 0.3 mg,(19.13 ±0.83)％ in CpG OND1826 0.45 rag,( 12.88±0.83)％ in CpG OND1826 0.15 mg+ IR,(20.57±2.37)％ in CpG OND1826 0.3 mg+ IR,and (28.17 ±3.31)％ in CpG OND1826 0.45 mg + IR group,and thus the apoptosis rate of every therapy group was higher than that in control ( t=11.15,7.91,17.82,39.48,24.73,16.61 and 17.05,P＜0.05).The apoptosis rates of CpG ODN1826 plus X-ray irradiation group were significantly higher than those in IR alone ( t =13.78,15.08 and 17.47,P＜0.05 ) or CpG ODN group (t=18.53,9.66and7.51,P＜0.05).Conclusions CpG ODN1826 can dramatically increase the efficiency of radiotherapy by inhibiting tumor growth and promoting lumor apoptosis.

Objective To explore the effect of ionizing radiation and cisplatin on the expression of Transducer of erbB2,1 ( TOB1 ) in human lung adenocareinoma SPCA-1 and LTEP-α-2 cell lines.Methods SPCA-1 and/or LTEP-α-2 cells were respectively irradiated with 2,4,6,8,and 10 Gy X-rays generated by a linear accelerator (with the source skin distance of 100 cm and dose rate of 200 cGy/min).The cell molecular samples were subtracted at 6,12,18,and 24 h after 6 Gy irradiation.For X-rays and cisplatin combination treatment,cells were divided into radiation group (6 Gy X-rays),cisplatin group (20 mol/L cisplatin),and combination group (6 Gy X-rays + 20 mol/L cisplatin).SPCA-1 and LTEP-α-2 cells without any treatment were used as control group.The relative levels of TOB1 mRNA and protein expression were detected by rigorously controlled semi-quantitative RT-PCR and Western blot analysis with quantitation of the mRNA/protein bands by densitometry.Results The expression level of TOB1 was significantly increased in both mRNA and protein level after radiation exposure (t =8.25-24.48,P ＜0.05).For time-dependent induction of TOB1,the expression was significantly increased 6 h after X-rays exposure (t =14.23-15.82,P ＜ 0.05 ).More significant increase of TOB1 expression was identified after the combination treatment of X-rays and cisplatin,compared to that of the radiation and/or cisplatin treatment alone (t =11.21-13.67,P ＜0.05).Conclusions lonizing radiation and cisplatin could upregulate the expression of TOB1 in lung cancer cells in both mRNA and protein levels.TOB1 may be a molecular target for ionizing radiation and cisplatin treatment in lung cancer and it may have potential implication in evaluating the curative efficiency of chemo-and radio-therapy.

Objective To explore the X-ray radiation dose to patients from different cardiovascular interventional procedures and analyze the dose-affecting factors.Methods In accordance with the A,B,C operators,442 patients undergoing cardiovascular interventional procedures were collected,including single coronary angiography (CAG),percutaneous coronary intervention ( PCI ),radiofrequency catheter ablation (RFCA),congenital heart disease intervention (CHD) and permanent cardiac pacemaker implantation (PCPI),to observe dose area product (DAP),cumulative radiation dose (CD),fluoroscopy time.Results CD values of patients in groups of CAG,PCI,RFCA,CHD,PCPI were (0.34 ±0.23),(1.33 ±0.76),(0.71 ±0.43),(0.27 ±0.22) and (0.92±0.42) Gy and DAP values were (34.18 ±23.33),(135.92 ±81.14),(79.79 ±50.66),(27.93 ±23.66),and (94.60 ±48.11 ) Gy·cm2,respectively.Fluoroscopy time were (4.82 ±3.73),( 16.64 ±9.01 ),( 17.04 ± 15.29),(9.60 ±5.97)and (7.31 ±6.45) min.DAP values and fluoroscopy time were highly correlated (r =0.84,P ＜ 0.05 ).Conclusions There is significant difference in radiation dose for cardiovascular interventional procedures.Radiation dose and fluoroscopy time are directly related to surgeons' proficiency in operations.Improvement of operation proficiency should be carried out to reduce the patients' radiation dose.