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Objective:To screen the kinase genes related to radioresistance by high-throughput method and provide a theoretical basis for clinical treatment strategy of oral squamous cell carcinoma.Methods:The tongue squamous carcinoma cell line Cal-27 was infected with lentivirus shRNA kinase library that contains 4 675 different shRNAs regulating 709 human kinase genes. The uninfected cells were removed by puromycin screening. Then, the cells were irradiated with different doses (0, 10, 15 cGy) and continued to culture for 3 d to enrich the differences among groups. Afterwards, the cell genomic DNA was extracted and the complete shRNA sequences were obtained by PCR.Different tags were labeled in shRNAs of each group. An illumina platform was used for next generation sequencing to acquire the shRNA abundance, and then the differentiated expressed genes among different groups were identified.Results:A total of 5 kinase genes (PKLR, IPMK, AURKB, ITPKB and DLG2) were screened out from irradiated cells. Knockdown of PKLR and IPMK increased radiation resistance, while knockdown of AURKB, ITPKB and DLG2 increased radiation sensitivity, and the high expression of these genes would lead to radiotherapy tolerance.Conclusions:In this study, 3 genes relative to radioresistance of oral squamous cell carcinoma were identified by using shRNA lentivirus library combined with next generation sequencing, but the underlying mechanism requires further exploration.
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Objective To explore the elementary properties of LiF (Mg,Cu,and P) thermoluminescent dosimeter (TLD) in dosimetry for tumor radiotherapy,and to provide a reliable basis for thermoluminescent dosimetry in clinical radiotherapy.Methods 60Coγ-ray and 6 MV X-ray were used for evaluation of the dispersion,repeatability,and dose response of LiF TLD.To meet the requirement of clinical radiotherapy,the effects of energy,dose (50-600 cGy),radiation dose rate (50-600 MU/min),and the angle of incidence for accelerator gantry (0°-± 90°) on TLD were determined and the respective correction factors were calculated.Results The errors of repeatability and dispersion of TLD were less than ±3％.There was a linear relationship between readout and irradiation dose within a certain range of irradiation dose.The minimal relative deviation of 0.3％ was obtained when 6 MV X-ray was used with a dose rate of 300 MU/min and an angle of incidence of 0°.Conclusions LiF TLD shows excellent repeatability,low dispersion,high stability,and strong linear correlation.It meets the international criteria and can be used for dose measurement in tumor radiotherapy.
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Objective To understand the status of the radiation therapy in sichuan province, analysis the development level of radiotherapy in the past five years in sichuan province,provide reference for the rational allocation of radiotherapy resources in the province, promote the healthy development of radiotherapy. Methods With reference to the surveys carried out by other provinces and the survey of sichuan province in 2009,to determine the survey schemes,survey projects. The survey covers all medical units of radiation therapy in the province, adopt the way of combination of questionnaire and on?the?spot visiting. Results There is a big progress in basic condition, treatment equipment, auxiliary equipment, verification equipment,personnel and application of new technologies. Compared with 2009 survey,multiple projects achieve a 50% or even more than 100% growth. Conclusions The rapid development of radiation oncology in sichuan province will ultimately benefit a large number of tumor patients in sichuan province. Patients will be treated with better environment,treatment technology and quality. At the same time,higher requirement of quality control for the entire province is put forward to us.
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Objective To investigate influence on dose distribution due to cavity and inhomogeneous structures using thermoluminescence dosimeters (TLD) and Chengdu phantoms.Methods A cavity 4 cm × 4 cm × 3 cm was made by a head and neck phantom and a lung phantom was cut into slices which were got a CT scanning and setup in a digital simulator.The TLD were pasted on edge and in the center of cavity structure and inhomogeneous structures.Treatment plans of different radiotherapy technologies were made generated and delivered on a linear accelerator.Then the TLD were read and analyzed.Results There were remarkable cavity effects of conventional single field,opposite fields and IMRT plans with 7 fields for head and neck phantom.There is similar effect in lung phantom.The more complexity the radiotherapy technology was the less cavity effect.Conclusions It is necessary to consider using more advanced radiotherapy technology or applying more fields to make treatment plans in order to decrease the cavity effect or similar effect when there are inhomogeneous structures.
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ObjectiveTo study the using of cerrobase as the compensation material in the intensitymodulated radiation therapy (IMRT) implementation and impact factors.MethodsWith therapy planning system (TPS) exported the radiation field intensity file (Dicom RT),through measuring the attenuation coefficient of cerrobase,to calculate the processing depth of AUTIMO 3D CNC corresponding for Dicom RT files at each pixel,then using the processed foam casting of Cerrobase,produced the required IMRT compensator.Through the MATRIXX testing the IMRT compensator in clinical implementation.At the same time we compared the MU of using multi-leaf collimator (MLC) and Cerrobase IMRT compensator for 10patients.ResultsWith cerrobase compensation IMRT can get similar dose or dose distribution to dose produced by TPS for point or plane dose,error is within 5％.To comparison with MLC,using cerrobase compensator has fewer treatment times ( (4.44±0.39) min:(5.71±0.57) min (t =10.82,P =0.000) )and fewer MU (462.5 ± 65.8) MU:(524.5±99.6) MU(t=3.14,P=0.012) ).Conclusions Comparison with MLC IMRT,the cerrobase compensation technique has an important application value with its unique advantages.This research provides an implemented method of IMRT radiotherapy for the primaryhospital.
