Objective To define the correlation between nasopharyngeal carcinoma (NPC) cell radiosensitivity and gene mutation in the ATM/PI3K coding region. Methods The gene mutation in the ATM/PI3K region of nasopharyngeal carcinoma cell lines which vary in radiosensitivity,was monitored by reverse transcription polymerase chain reaction (RT PCR) and fluorescence marked ddNTP cycle sequencing technique.Results No gene mutation was detected in the ATM/PI3K region of either CNE1 or CNE2.Conclusion Disparity in intrinsic radiosensitivity between different NPC cell lines depends on some other factors and mechanism without being related to ATM/PI3K mutations.

Objective To compare the accuracy of output factor calculation for rectangular inserts of electron beams by using three kinds of algorisms: square root, one dimensional formula and area periphery ration. Methods The differences between the values of output factor calculated by these three algorithms mentioned above and the results measured by ionization chamber for seven rectangular inserts were compared. Results When beam energy was fixed, the difference between calculated and measured output factors was larger for area periphery ration algorithm than that of the square root or one dimensional formula algorithms. The electron cone size, beam energy and rectangular inserts size all had some effect on the value of output factor calculated by the three algorithms. Conclusions The area periphery ration algorithm is not recommended for clinical use because of its great deviation. One dimensional formula and square root algorisms possess a good accuracy. One dimensional formula is superior to square root algorithm, but square root algorithm is more practical for clinical use.

Objective To assess and delineate the dosimetric shortcomings of conventional radiotherapy planning,as compared with the three dimensional treatment planning system, and to obtain a better technique in the treatment of lung cancers.Methods Thirteen patients with stage ⅢA ⅢB non small cell lung cancer were chosen in the present study. Using the Cadplan 6.0.8 treatment planning system , three different methods of radiotherapy planning: conventional planning, conventional and conformal planning, and conformal planning were designed for each patient. The total radiation dose was 66 ?Gy and DVHs were used to assess the dosimetric distribution in the gross tumor volume and the surrounding organs at risk. Results No significant dosimetric disparity in the target volume was found among the three designs, according to anticipated therapeatic requirements. The conformity indices were 0.13,0.24 and 0.35 for these three radiotherapy designs. The mean lung volumes which received radiation dose of≥20?Gy were 32%,26% and 25%.The mean maximum dose at the spinal cord were 42?Gy,49?Gy and 33?Gy.The mean esophageal volume which received radiation of ≥50?Gy were 32%,34% and 22%, and the mean radiation dose to the heart were 18?Gy,15?Gy and 12?Gy,respectively. Conclusions Conventional radiotherapy planning is able to meet the demands of dosimetric requirements for radiation treatment of lung cancers. The three dimensional conformal radiation therapy planning system is able to provide superior delivery of high dose to the target volume without inflicting too high a risk to the surrounding normal tissues and organs.

Objective To analyze the prognostic factors and evaluate the effect of stereotactic radiosurgery for patients with multiple brain metastases. Methods Comparison was made in 53 such patients treated by stereotactic radiosurgery plus radiotherapy and 53 treated by radiotherapy alone. Patients were matched paired according to the following criteria: age, Karnofsky performance scale(KPS) before treatment, extent of systemic cancer and number of brain metastasis.Fourty patients had stereotactic radiosurgery, 13 patients stereotactic fractionated radiosurgery. In the stereotactic radiosurgery group, the patients were given a mean marginal dose of 20?Gy. Methods of stereotactic fractionated radiosurgery was 4 12?Gy per fraction, twice a week to a total dose of 15 30?Gy. Whole brain radiotherapy was given immediately after stereotactic radiosurgery. For patients treated by radiotherapy alone, the entire brain was treated by 30 40?Gy in 3 4 weeks. Results The median survival was 11.6 months in stereotactic radiosurgery plus radiotherapy and 6.7 months in radiotherapy alone. The one year survival rate and one year local control rate were 44.3%,17.1% and 50.9%,13.2%. Those with KPS increased after treatment gave 1 year survivals of 69.8% and 30.2%, respectively. The validity rates in CT or MRI three months after treatment were 82.0% and 55.0%.The difference in the two groups was found to be statistically significant (P

Objective To evaluate the effects of prophylactic cranial irradiation (PCI) on the survival and brain metastatic rates in patients with limited stage small cell lung cancer (SCLC) in complete remission. Methods Fifty one patients with limited stage SCLC in complete remission after chemoradiotherapy were randomly divided into prophylactic cranial irradiation (PCI) group (n=26) and control group (n=25). Patients in PCI group received irradiation to a dose of 25.2～30.6?Gy by 1.8～2.0?Gy per fraction. With the survival rates of the two groups analyzed by life table and compared by Log Rank test, the difference in cranial metastatic rates between the two groups were tested by ? 2 test. The patients' clinical features such as age, sex, effect of treatment before PCI were comparable between the two groups. Results The incidence of cranial metastasis was 3.8% in the PCI group as compared with 32.0% in the control group, with the difference significant (? 2=5.15, P= 0.02 ). The 1 , 3 , 5 year survival rates were 84.6%, 42.3%, 34.6% in the PCI group and 72.0%, 32.0%, 24.0% in the control group, with no significant difference between the two groups (? 2=2.25, P=0.13). No serious complications were observed in patients who received PCI. Conclusion For patients with limited stage SCLC complete response after chemoradiotherapy, PCI can decrease the incidence of cranial metastasis and tends to improve the survival rate.

Objective To evaluate 18 F deoxyglucose positron emission tomography (FDG PET) in the detection of suspicious recurrence in head and neck cancers , as compared with CT/MRI imaging. Methods Thirty seven patients with clinically suspicious recurrences in head and neck cancers underwent FDG PET, with 34 checked with CT/MRI imaging. The final diagnosis of recurrence were proved by pathology or clinical following up. Results FDG PET detected recurrence successfully in 32 of 37(86.5%) patients with 3 false positives and 2 false negatives. The FDG PET sensitivity, specificity and accuracy in defining local recurrence were 91.7%, 76.9%, 86.5%, respectively; and those of CT/MRI were 68.2%, 75.0%, 61.8%, respectively. Conclusion In comparison with CT/MRI, FDG PET possesses a higher accuracy in detecting recurrence in head and neck cancers.

Objective To study the effect of arsenic trioxide(As 2O 3) combin ed w ith radiation on the killing of ovarian cancer cells. Methods Using MTT and FCM to detect the cytotoxic and apoptosis at different As 2O 3 concentrations combined with 2 an d 8 ?Gy radiation on ovarian cancer cells(SKOV-3). Radiation survival curves were det ermined by cloning assay with 5?mol/L As 2O 3 combined with 2, 3, 4, 6, 8 and 12?Gy radiation. Curve was used to evaluate the effect of cell killing. Results ⑴ Inhibition of cell proliferation seemed more dependent on the increase of As 2O 3 concentration, ⑵Cell survival rate was lower in the combination of As 2O 3 an d r adiation than As 2O 3 alone, ⑶The apoptosis ratio was increased in 2?Gy and As 2O 3 with increase in As 2O 3 concentration, ⑷D q , D 2 value was decr eased in t he combined As 2O 3 and radiation than radiation only (D q: 1.44 vs 2.78, D 0: 0.85 vs 1.30, SF 2: 0.42 vs 0.87), with radiation enhancement ratio of 1.53 and 2.0 7 according to D 0 value and SF 2. Conclusions Arsenic trioxide is able to enhanc e radiation effect obviously ,especially at lower radiation dose.

Objective To compare the treatment effects and toxicity of late co urse accelerated hyperfractionation radiotherapy (LCAFR), LCAFR plus concurren t chemotherapy (LCAFR+C) and conventional fractionation radiotherapy(CFR) on esop hageal cancer. Methods 150 patients with squamous carcinoma of thoracic esophag us were divided randomly into three groups: 1.CFR group, patients were irradiate d 2.0?Gy/f, 5 times a week, to a total does of 60?Gy. 2. LCAFR group, patients wer e first irradiated with CFR to 30?Gy, then followed by 1.5?Gy/f bid, at more t han 6 hours' interval, to the total dose of 60?Gy. 3.LCAFR+C group: The radiotherap y technique was the same as the LCAFR group, but weekly 20 mg DDP and 500 mg 5-Fu wer e added simultaneously for 5 weeks. Results All three groups completed their tre atment course. Of CFR, LCAFR and LCAFR+C groups, the 1-,2-,3- and 4-year sur viva l rates were 54%, 30%, 18%, 18%; 76%, 56%, 44%, 42% and 82%, 62%, 50%, 44%. The 1-,2-,3- and 4-year local control rates were 40%, 32%, 26%, 24%; 72%, 60%, 5 6%, 54% and 78%, 66%, 60%, 56%, with obvious better results in the latter two groups (P0.05). The acute toxic effect was severer in the LCAFR+C g roup than in the other two, with the difference significant between the LCAFR+C and CFR group, bu t not between the LCAFR and CFR group. The tolerance of the patients to LCAFR wa s better than that of LCAFR+C group. There were no significant differences in la te complications and causes of death between the three groups. The main cause of death was local recurrence and uncontrolled primary disease, which were signifi cantly lower in the LCAFR and LCAFR+C groups than in the CFR group. Conclusions Both late course accelerated hyperfractionation radiotherapy and late course acc elera ted hyperfractionation radiotherapy plus chemotherapy can significantly improve the local control and survival of esophageal cancer, but the latter has increase d toxicity. Concurrent small dose chemotherapy can not lowered the remote metas tatic rate.

Objective To investigate the protective effect and it's possible mechanism of Tanshinone ⅡA in radiation-induced pulmonary fibrosis.Methods Having the right hemithorax of female Wistar rats irradiated(30?Gy) in 10 fractions within 14 days by 6 ?MV photons,the radiation-induced pulmonary fibrosis animal model was established.In the treatment group,sodium Tanshinone ⅡA sulfonate(15?mg/kg) was given by intraperitoneal injection 1 hour before each fraction of irradiation.Five months after irradiation,the difference of the histopathological changes,the hydroxyproline content and expression of TGF-?1 between the radiation alone group,tanshinone plus radiation and control group were analyzed by HE stain,Massion stain,immunohistochemical methor and reverse transcriptase polymerase chain reaction(RT-PCR) method.Results The histopathological comparison revealed the protective effect of Tanshinone ⅡA.The content of hydroxyproline was(21.99?3.96),((38.25?)(7.18)),(28.94?4.29)??g/g in the control group,radiation alone group and radiation plus Tanshinone ⅡA.The expression of TGF-?1(mRNA and protein) was reduced by Tanshinone ⅡA.Pathological changes of the pulmonary fibrosis was reduced by Tanshinone ⅡA yet.Conclusions Our study shows that Tanshinone ⅡA can inhibit radiation-induced pulmonary fibrosis,and the possible mechanism of its may be made possible through down-regulating the expression of TGF-?1 in the irritated lung tissue.

Objective To study the effect of transcatheter arterial chemoembolization(TACE) combined with three-dimensional conformal radiotherapy(3DCRT) for inoperable primary liver cancer.Methods Ninety-six such patients were prospectively randomized to TACE therapy alone group(TACE group-,47 patients) and TACE+3DCRT group(combined group-,49 patients).Results The overall 1-,2-,3-year survival rate was 82%,63%,43% in the combined group.It was 55%,28%,15% in the TACE group.The difference between the two groups was significant(P0.05).Conclusion Transcatheter arterial chemoembolization combined with three-dimensional conformal radiotherapy is more effective than transcatheter arterial chemoembolization therapy alone for inoperable primary liver cancer,without inflicting more treatment-related toxicities.