Objective:To evaluate the application value of diffusion tensor imaging (DTI) in guiding the postoperative radiothera-py plan of the gliomas adjacent to the corticospinal tract (CST). Methods:Thirty patients with gliomas adjacent to the CST underwent routine magnetic resonance imaging (MRI) contrast-enhanced scanning and DTI after radiotherapy. Tractography data sets were ac-quired and were fused with the images of corresponding anatomical MRI and computed tomography. The acquired data sets of radio-therapy planning system were imported to assist with the delineation of the target volume, organs at risk, and CST. Two sets of radio-therapy plan, which considered or did not consider the dose protective effect of the CST, were formulated and compared using the treat-ment technique of intensity modulated radiotherapy. Results:The protective radiotherapy and unprotected plans both achieved the thera-peutic dose to the target volume and the protection of the routine organs at risk. In the protective dose (with an optimization program that considered the dose reduction of CST), the maximum and mean radiation doses suffered by the patients' ipsilateral and contra-later-al CSTs were lower compared with the unprotected plan (P<0.05). Conclusion:DTI can identify the location and shape of CSTs, and their relationship with the postoperative radiotherapy target of gliomas. These findings contribute to the formulation of a protective ra-diotherapeutic regimen to keep the CST from the maximum and the mean radiation doses to the largest extent, thereby decreasing the possibility of nerve damage after radiotherapy.

Objective To evaluate the ability of 3-AB to sensitize the human esophageal carcinoma cell strain (CaEs-17) to radiation in v/tro and its mechanisms. Methods CaEs-17 cells were treated with 3-AB at 0, 2.5, 7.5 mmol/L and given irradiation O, 3, 6, 9, 12 Gy. 3-AB concentration in each group was made dose-survival curve using multi-target single-hit maiths model by clonogenie assay. MTT assay was performed to observe the survival of irradiated cells.comet assay and metaphase chromosome analysis were used to measure the DNA damage degree and chromosome aberration of CaEs-17 cell after 3-AB treatment and irradiation. Results Cell survival experiments showed SER of 1.21, 1.52 for 2.5 mmol/L, 7.5 mmol/L 3-AB respectively using multi-target single-hit maths model. The survival fraction of irradiated CaEs-17 cell was decreased after 3-AB treatment. DNA damage and the chromatid breakage number of irradiated CaEs-17 cells were increased after 3-AB treatment. Conclusions 3-AB, a PARP inhibitor, can enhance the radiosensitivity of human esophageal carcinoma cell strain (CaEs-17). DNA damage repair inhibition by 3-AB might be one of the mechanisms.

Objective To investigate the clinical value of blood oxygen level-dependent functional magnetic resonance imaging (BOLD-FMRI) in guiding the dose reduction and functional protection of the motor cortex during postoperative radiotherapy for brain astrocytoma.Methods This study included 27 brain astrocytoma patients with tumors near the motor cortex,who underwent routine MRI and BOLD-FMRI before postoperative radiotherapy.The location and scope of the motor cortex,which were acquired based on BOLD-FMRI results,were marked on positioning CT images,so that the motor cortex would be dealt with as organs at risk.The dose to the motor cortex was reduced as much as possible while ensuring the therapeutic dose to the target area.Finally,the radiotherapy plan that would reduce the mean received dose of the motor cortex was formulated and compared with the routine plan that could not reduce the received dose.Results With the protective radiotherapy plan,the mean received dose of the motor cortex decreased 0.76％-59.20％ (mean 30.78％) on the affected side and 23.33％-68.30％ (mean 48.07％) on the unaffected side;the coefficients of variation were 71.41％ on the affected side and 36.71％ on the unaffected side.Conclusions BOLD-FMRI can help to reduce the received dose of the motor cortex while ensuring the therapeutic dose to the target area when formulating the postoperative radiotherapy plan for brain astrocytoma,thus protecting the motor function and improving patients' quality of life.

Objective To analyze the feasibility of incorporation of tracking visual pathway fiber bundles by diffusion tensor imaging ( DTI) in computed tomography ( CT) simulation to develop a protective radiotherapy regimen for cerebral gliomas.Methods A total of 31 patients with cerebral gliomas who were admitted to our hospital from 2013 to 2015 and planed to receive postoperative radiotherapy were enrolled as subjects.All patients underwent CT simulation, conventional or contrast-enhanced magnetic resonance imaging, and DTI.The obtained DTI images of visual pathway fiber bundles were fused with 3DT1 anatomical scans and then imported into the treatment planning system.A protective treatment plan ( setting the entire visual pathway fiber bundles as organs at risk (OARs)) and a conventional treatment plan were made for intensity-modulated radiotherapy ( IMRT) .Comparison of treatment outcomes was made by paired t test.Results There were no significant differences in the conformity index and heterogeneity index of the planning target volume between the two treatment plans ( P=0.875,0.597), both of which had sufficient radiation doses to the target volume and conventional OARs protected.For the patients undergoing the protective treatment plan, the Dmax and Dmean values were reduced to 9.01%and 9.05%, respectively, in the ipsilateral optic tract and to 17.96%and 15.52%, respectively, in the contralateral optic tract;the Dmax and Dmean values were reduced to 5.37%and 5.48%(P=0.000), respectively, in the ipsilateral optic radiation tract and to 12.89%and 11.21%( P=0.000) , respectively, in the contralateral optic radiation tract.Conclusions The protective treatment plan based on CT simulation combined with the display of visual pathway fiber bundles by DTI can reduce the radiation dose to the entire visual pathway fiber bundles, which keeps the risk of visual dysfunction after radiotherapy as low as possible.

Objective To investigate the clinical value of blood oxygenation level-dependent functional magnetic resonance imaging(BOLD-fMRI)in the protection of visual function during postoperative radiotherapy for occipital lobe gliomas. Methods Twenty-eight patients with occipital lobe gliomas receiving postoperative radiotherapy from 2014 to 2016 were enrolled as subjects. All patients underwent computed tomography(CT) simulation,conventional MRI,and BOLD-fMRI before radiotherapy. The location and scope of the visual cortex on 3DT1anatomical images were used to guide the labeling of the visual cortex on simulated CT images. A visual cortex protective radiotherapy plan and a conventional radiotherapy plan were made by intensity-modulated radiotherapy. The feasibility of the visual cortex protective radiotherapy plan was evaluated using conformity index(CI),homogeneity index(HI),Dmax,and Dmeanfor planning target volume(PTV)and Dmaxand Dmean to the visual cortex. Results For the two plans, if the effective dose to target volume was guaranteed and the doses to conventional organs at risk were acceptable, there were no significant differences in CI or HI for PTV between them(P=0.874,P=0.602).Compared with the conventional radiotherapy plan,the Dmaxand Dmeanto the ipsilateral visual cortex were reduced by 8.40% and 9.25%, respectively, while the Dmaxand Dmeanto the contralateral visual cortex were reduced by 13.26% and 14.77%, respectively, in the protective radiotherapy plan. Conclusions With a guaranteed prescribed dose to target volume and BOLD-fMRI used as a guide, the visual cortex protective radiotherapy, compared with the conventional plan, can reduce the dose to the visual cortex and protect the corresponding functional areas.

Objective: To investigate the impact of bladder filling status on the movement of uterine and on the volume of organs at risk(OAR), so as to provide theoretical basis for individualized internal target volume (ITV) and planning target volume (PTV). Methods: Simulation CT images for a total of 27 patients with locally advanced cervical cancer were acquired with empty bladder, 1.0 h after bladder filling, 1.5 h after bladder filling, respectively. The volumes of uterine corpus, cervix, OARs, CTV and PTV 1.0 h after bladder filling were delineated. The impact of bladder filling status on the displacements of cervix and corpus, volumetric changes of rectum, small intestine, and the volumes of small intestine, bladder and rectum within PTV were analyzed. The correlation between bladder filling status and uterine displacement and volume of OAR was also investigated, as well as the volume of cervix and corpus in the PTV with empty bladder and 1.5 h after bladder filling. Results: Bladder filling status is different for individual cases. The maximum movement range of cervix and uterine body with bladder filling state was 0-3.04 cm and 0-4.31 cm respectively. The anterior displacements of corpus (F=7.818, P<0.05), the volumetric changes of blander, as well the volume of bladder and small intestine in the PTV (F=46.197, 44.609, 29.546, P<0.05) were significantly different between different bladder filling status. The bladder filling status was correlated with the displacements of the anterior of corpus, volumetric changes of small intestine, and the volumes of bladder and small intestine within the PTV (r=-0.232, -0.298, 0.915, -0.336, P<0.05). The volumes of cervix and corpus out of the PTV were significantly different between the empty bladder and 1.5 h after bladder filling (t=-1.326, -1.559, P<0.05). Conclusions Bladder filling status was different for individual patients. The displacements of the anterior of the corpus were significantly affected by the bladder filling status. Increasing the anterior margin of PTV was recommended. The consistency of bladder filling status was critical for the precise cervical cancer IMRT.

Objective:To investigate the clinical application of cervix-uterine internal target volume (ITV) in volume-modulated arc therapy (VMAT) for cervical cancer under different bladder filling conditions, aiming to obtain more accurate planning target volume (PTV).Methods:Sixty-two patients with cervical cancer receiving radiotherapy rather than surgery were selected and randomly divided into the study ( n=31) and control groups ( n=31). In the study group, individualized ITV, PTV and PTV margin were obtained under three bladder filling status by localization CT scan to compare the VMAT. The target area and organs at risk (OARs) within the target area were statistically compared between two groups. The target missing rate in CBCT, adverse events and short-term efficacy of radiotherapy were analyzed in two groups. Results:There was no significant difference in the volume of target area and OARs in the target area between two groups (both P>0.05). In the study group, the target missing rate and target missing volume were significantly lower compared with those in the control group (both P<0.05). There was no significant difference in the incidence of acute radiation-induced adverse events between two groups ( P>0.05). The 1-, 2-year overall survival and progress-free survival did not significantly differ between two groups (all P>0.05). One patient in the study group had uterine recurrence and 2 cases in the control group. Conclusion:Application of individualized cervix-uterine ITV and PTV in definitive VMAT under different bladder filling conditions can improve the accuracy of target area contouring and improve the local control rate in cervical cancer patients.