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Objective To investigate the relationship between RKIP expression and the efficiency of radiotherapy in NPC patients and evaluate the possibility of using RKIP as a predictor of radiosensitivity.Methods A total of 180 patients with NPC in Sun Yat-sen University Cancer Center without evidence of distant metastasis at initial diagnosis were enrolled in this study,who had received intensity-modulated radiotherapy alone.Patients were classified into 2 groups according to criteria below:patients with biopsy proven recurrent diseases occurring at nasopharynx and/or neck within 5 years after radiotherapy were classified as the radioresistant group.The pathological type at relapse was the same as the previous one before treatment.Patients with a minimum follow-up of 5 years after radiotherapy without evidence of recurrence at the original site of the tumor were classified as the radiosensitive group.Patients in the 2 groups were matched according to the factors related with radiosensitivity.RKIP was examined by immunohistochemical staining before radiotherapy.The relationship between RKIP expression and the effect of radiotherapy were analyzed.Results The positive rate of the RKIP expression in the radiosensitive group versus the radioresistant group was 80.0％ versus 26.7％.The positive rate (x2 =12.498,P ＜0.01) and the intensity of the RKIP expression (x2 =51.429,P ＜ 0.01) were significantly different between 2 groups with a negative correlation with radio-resistance to NPC (r =-0.344,-0.535,respectively,P ＜ 0.01).Based on the RKIP expression,the radiosensitivity,specificity,accuracy,positive predictive value,negative predictive value,false positive and false negative were predicted as follows:80.0％,73.3％,77.2％,75.0％,78.6％,26.7％,and 20.0％,respectively.Conclusions RKIP protein shows negative correlation with radioresistance to NPC and could serve as a biomarker in preliminarily screening the intrinsic radiosensitivity of NPC.
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Objective To discuss the feasibility of Monte Carlo N-particle transport code(MCNP)simulated calculation.Methods The calculation in water phantom was contrasted with the practical measurements and the reported values using the percent depth dose(PDD)curve and normal peak scatter factor.Results There Was no significant difference between calculated and measured results in the 10 cm×10 cm field(t＝-0.41,P>0.05),however,there were significant differences in the 5 cm×5 cm field(t=7.2,P<0.05)and in the 12 cm×12 cm field(t=-4.6,P<0.05).There was no significant difierence between the calculated results and the reported values(t=-1.91,P>0.05).In the same radiation field,the PDD decreased as the depth increased,but increased as the size of the radiation field increased at the same depth.PDD and normal peak scatter factor were both important parameters for calculation of prescribed dose.Conclusions It is possible to establish a set of accurate and comprehensive percent depth doses and normal peak scatter factor parameters so as to provide the basis of clinical use, quality assurance and quality control for radiotherapy.
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Objective To study the CT characteristics of inflammatory pseudotumor of the liver(IPL).Methods 16-slice spiral CT findings of IPL in 16 cases were analysed retrospectively.The CT values of IPLs and the liver tissue surrounding the lesions were measured on plain and contrast-enhanced CT scans.Results Totally 18 lesions in 16 cases were detected by CT,most of them(16 lesions) located in the right lobes of liver.The lesions appeared as low-density,round or round-like,or irregularity in sharp.Dynamic enhanced CT scan showed the lesions no or slight enhancement in arterial phase,slight to moderate enhancement in portal vein phase.A part of the lesions showed ring enhancement surrounding the lesions,nodular or fiber stripped enhancement in the center of lesions,and the branches of the portal vein passesed through the lesions.In enhanced degree of the lesions,there was not statistical difference in arterial phase compared with plain CT scans,but there were statistical differences in portal-venous phase compared with plain scan and arterial phase.In the liver around the lesion,the enhanced degree had statistical difference in artery phase and portal-vein phase compared with plain CT scans.Conclusion Dynamic enhanced CT scan shows that IPL is of hypovascularity,it's of characteristic in the portal-venous phase and delayed phase.