ABSTRACT
Objective To investigate the accuracy and application value of optical surface monitoring system in intensity modulated radiotherapy for thoracic tumors patients.Methods Twenty-eight patients with thoracic tumors were included.During each treatment fraction,the patients were immobilized with body surface markers and laser lamps.The surface images obtained by the optical surface monitoring system were registered with the reference images and recorded during the CBCT scan.The translation and rotation errors of x (left-right),y (craniocaudal) and z (anterior-posterior) axes were recorded.After scanning,the CBCT images were registered with the planned CT images and the translation and rotation errors of x,y and z axes were recorded.The setup errors of these two image systems were analyzed and corrected before each treatment.The correlation between the two sets of setup errors were analyzed with Pearson test,and systematic error (∑) and random error (σy) were also calculated.The consistency of the two image systems was evaluated with the Bland-Altman method and the 95％ limits of agreement were calculated.Results There was a good correlation between these two groups,and the correlation coefficients were 0.79,0.62,and 0.53 in x,y and z axes,respectively.The ∑/σr of the optical surface monitoring system were 0.7 mm/1.5 mm,0.9 mm/1.8 mm and 0.9 mm/1.5 mm in x,y and z axes,respectively.The ∑/σ of CBCT were 0.8 mm/1.6 mm,1.3 mm/1.9 mm and 0.7 mm/1.5 mm in x,y and z axes,respectively.The 95％ limits of agreement of translations direction were (-2.0-2.3),(-3.4-3.6) and (-3.3-2.4) mm,and the 95％ limits of agreement of rotation direction were (-2.0 to 1.6)°,(-2.0 to 1.4)° and (-1.6 to 1.6)° inx,y and z axes,respectively.Conclusions The optical surface monitoring system is an effective image guide tool,which can quickly and accurately verify the patient's position and improve the position accuracy.It can be applied for positioning in the intensity modulated radiation treatments for the thoracic tumor patients.
ABSTRACT
Objective To analyze the setup errors by cone-beam computed tomography (CBCT) for breast cancer patients who were immobilized with neck and breast thermoplastic mask and received intensity modulated radiation therapy (IMRT), and to calculate the external margins from the clinical target volume (CTV) to the planning target volume (PTV) (MPTV) of tumors. Methods Twenty-five breast cancer patients who were immobilized with neck and breast thermoplastic mask and received IMRT in the Oncology Department of Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology from November 2016 to June 2017 were enrolled. The position of the patients were verified by CBCT before treatment . The linear and rotation errors of the X, Y and Z axes were analyzed by online bone registration. The systematic errors (Σ) and random errors (σ) of the patients were also calculated, and then the margins from CTV to PTV margins were calculated based on MPTV=2.5Σ+0.7σ. 25 patients'height, weight, body mass index (BMI) and the maximum diameters of CTV in the lateral, longitudinal and vertical directions were recorded, and the relation between the setup errors and the above mentioned was analyzed by using Spearman method. Results A total of 174 CBCT scans for 25 breast cancer patients were completed. The group Σ were 1.40 mm, 1.50 mm and 1.20 mm, and rotation errors were 0.9°, 0.7° and 0.8° at the X, Y and Z axes, respectively. The group σ were 2.20 mm, 3.00 mm and 1.40 mm, and rotation errors were 0.7°, 0.6° and 0.7° at the X, Y and Z axes, respectively. MPTVwas recommended as 4.90 mm, 6.00 mm and 3.90 mm at the X, Y and Z axes, respectively. There was no correlation between the height, weight, BMI of the patients and the setup errors (all P ＞ 0.05). However, there was a significant correlation between the maximum lateral, longitudinal diameters of the CTV and the setup errors (rs= 0.406, P= 0.044; rs= 0.512, P= 0.009). Conclusions The neck and breast thermoplastic mask can improve the diagnostic accuracy of radiotherapy in breast cancer patients. The data of setup errors verified by CBCT can provide meaningful references for the setting of MPTV.
ABSTRACT
This study examined the role of PI3K/Akt pathway in radiosensitization of DNA damage of cervical carcinoma cells. The 50% inhibition concentration (IC(50)) of cisplatin and docetaxel in HeLa cells was detected by Mono-nuclear cell direct cytotoxicity assay (MTT) in vitro. HeLa cells were treated by cisplatin/docetaxel of 10 percent of IC(20) alone or combined with LY294002 for 24 h, and then radiated by different doses of X-ray. The cell survival ratio was obtained by means of clone formation. One-hit multi-target model was fitted to the cell survival curve to calculate dose quasithreshold (Dq), mean lethal dose (D(0)), 2Gy survival fraction (SF(2)) and sensitization enhancement ratio (SER). The pAkt and total Akt expression was detected by Western blotting and DNA damage by neutro-comet electrophoresis. The HeLa cells were randomly divided into 7 groups in terms of different treatments: Control; radiation treatment (RT) group; LY294002+RT group; cisplatin+RT group; docetaxel+RT group; LY294002+cisplatin+RT group; LY294002+docetaxel+RT group. The apoptosis ratio of each group was measured by flow cytometry. The results showed that docetaxel and cisplatin significantly enhanced the phosphorylation of Akt in radiation-treated HeLa cells. The Dq, D(0) and SF2 in LY294002-contained groups were lower than those in docetaxel or cisplatin+RT group. The SER in the LY294002+docetaxel+RT group was 1.35 times that of the docetaxel+RT group, and that in the LY294002+cisplatin+RT group 1.26 times that of the cisplatin+RT group. The Comet electrophoresis showed that tail distance in the LY294002+cisplatin+RT group or LY294002+docetaxel+ RT group was longer than in the cisplatin+RT group or docetaxel+RT group. The apoptosis ratio in the LY294002+cisplatin+RT group or LY294002+docetaxel +RT group was higher than in the cisplatin+RT group or docetaxel+RT group. It was concluded that inhibiting PI3K/Akt pathway can increase the effect of docetaxel and cisplatin on the radiosensitivity of HeLa cells and DNA damage resulted from radiation.