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Objective:A new algorithm based on Hough transform (HT) was proposed to improve the accuracy and stability of the film image analysis of Automatic Quality Assurance (AQA) test, and to explore the influence of the resolution of film image on the test results.Methods:Nine pairs of films were obtained for AQA modules in this study. Firstly, the median filter was used to preprocess the grayed-out film image to remove noise interference. Then, a global threshold was utilized to binarize the image. The images were edge-detected and the film edge line was extracted by Hough transform. The film image was transformed to the correct position. Finally, the edge of the field shadow circle and the shadow circle of the tungsten ball were extracted by the edge detection method and Hough transform. The radial error was finally obtained by analyzing the concentricity.Results:There was no significant difference in the accuracy between the test results yielded by the HT method and the AQA software ( P>0.05). The difference in the standard deviation of the test results was statistically significant ( P=0.027), indicating that the algorithm increased the stability while ensuring the accuracy of film analysis. Increasing the resolution of film scanning failed to significantly improve the accuracy and stability of film analysis in both two methods. Conclusions:The algorithm used in this study can eliminate the human error caused by film scanning placement while ensuring the accuracy of film analysis, providing a more stable way for the AQA test of the CyberKnife system.
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Objective:To compare the dosimetric difference between knowledge-based planning (KBP) volumetric modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) models for predicting the dose distribution during IMRT, aiming to investigate the feasibility of VMAT model to predict the IMRT plans.Methods:Fifty prostate cancer patients who had completed radiotherapy were selected. Manual planning was performed on each selected patient to generate the corresponding IMRT and VMAT plans. The IMRT and VMAT manual plans of the 40 randomly-selected patients were adopted to generate the KBP VMAT and IMRT models. The remaining 10 patients were utilized to predict IMRT plans. VMAT library-derived IMRT model (V-IMRT) and IMRT library-derived IMRT model (I-IMRT) were generated. Dosimetric parameters related to organ-at-risks (OARs) and planning target volume (PTV) were statistically compared among the manual IMRT (mIMRT), V-IMRT and I-IMRT plans.Results:Compared with the mIMRT plan, I-IMRT could significantly better control D max of the PTV ( P=0.039), whereas V-IMRT and I-IMRT plans could better protect the bladder and bilateral femoral heads (both P<0.05). V-IMRT plan could better protect the D max of bilateral femoral heads and the D 15% of the right femoral head (both P<0.05), whereas no significant difference was observed in other OARs and PTV (all P>0.05). Conclusions:Compared with the manual plans, KBP IMRT plan has significant advantages in protecting the OARs. KBP VMAT and IMRT models are both feasible in clinical practice, which yield equivalent accuracy for predicting IMRT plan.
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[Abstact] Objective To analyze the related parameters of the treatment plans for the pancreatic cancer with the Cyber-knife system.Methods The clinical data of 129 patients with single-target pancreatic cancer for the first time who underwent CyberkKnife radiosurgery between January 2017 and December 2017 in Shanghai Changhai Hospital were retrospectively analyzed.The parameters were all selected from the MultiPlan @4.0.2 treatment planning system and the data were analyzed.Results The volume of the targets in 129 patients with pancreatic cancer was 3.355-238.936 cm3,with the average volume of 51.43 ± 55.64 cm3.Patients were averagely treated for 5 to 8 sessions,and the average prescription dose was 6 Gy × 6 fraction,which equaled to 58 Gy in the biological equivalent dose (BED).The collimators with 20 mm and 15 mm accounted for up to 31％ and 27％,respectively,which were the top 2 options.The finally designed the conformal index(CI),new conformal index(nCI),and the homogeneity index were 1.14 ± 0.09,1.29 ± 0.09 and 1.42 ± 0.04,respectively.The coverages of tumor target was 80.3％-95.6％,with the average of 90.0 ± 4.6％.The treatment nodes,beams and Mus are 79,180 and 7 060 in average.The estimated treatment time was 42 ± 8 minutes.The organs at risk can be protected very well.Conclusions Reasonable Cyber-knife treatment plan can guarantee that stereotactic body radiation therapy can effectively treat Pancreatic Cancer.
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Objective To evaluate the short-term therapeutic efficacy of Cyberknife in alleviating the pain of locally advanced pancreatic cancer (LAPC) and explore the application of DWI in the pain evaluation.Methods Visual analogue scale (VAS) and Quality of life score KPS were conducted in 36 LAPC patients before and 1 month,3 month after radiotherapy,who underwent conventional MRI examination and DWI scan.The changes of VAS and KPS scores were observed before and after the treatment,as well as the apparent diffusion coefficients (ADC) changes of region of interest (ROI) in the DWI images,and the correlation of ADC with KPS and VAS was analyzed.Results VAS before and at 1 month and 3 month after the treatment was (4.89 ± 2.89),(1.08 ± 2.06) and (0.51 ± 1.48).KPS before and at 1 month and 3 month after the treatment was (72.47 ± 14.74),(93.33 ± 10.69) and (92.86 ± 10.73).ADC of DWI before and at 1 month and 3 month after the treatment was 1.47 ± 0.28,1.79 ± 0.33 and 1.94 ± 0.41,and the differences were statistically significant (all P values ＜0.001).VAS was obviously decreased at 1 month and 3 month after the treatment,while KPS and ADC were greatly increased,and the differences were statistically significant (P value ＜ 0.05).There was no statistical difference between those at 1 month and those at 3 month.There was no obvious correlation between ADC and VAS and KPS at 1 month and 3 month after the treatment.Conclusions After Cyberknife treatment,the pain was obviously relieved and the life quality was greatly improved within short period,but ADC of DWI can not sensitively monitor the changes of the pain.
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Objective To determine the effectiveness and safety of stereotactic body radiotherapy (SBRT)-CyberKnife for oligometastatic prostate cancer.Methods From May 2012 to February 2017,31 patients treated by CyberKnife were retrospectively reviewed,with a median age of 67 years(range 52 to 83 years),including 50 oligometastatic and 2 primary prostate cancer patients.The median PSA level was 8.4 ng/ml(range 0 to 300.0 ng/ml) and PSA test was performed every month.PSA progression-free survival (PSA-PFS),time to initiation of androgen deprivation therapy (ADT) and local control rate (LCR) were measured as the main outcomes.Results SBRT was well tolerated and were performed as planned in all patients.No SBRT related acute or late toxicities were observed.No bone fracture was observed in patients treated by bony targeted radiotherapy.The median follow-up after SBRT was 20.7.months (range 1.2-58.3 months).The median PSA-PFS was 5.3 months (range 0-58.3 months).1-year,2-year,and 4-year PSA-PFS was 52.0％,36.7％ and 36.7％ respe ctively.PSA level decrease was observed in 21 oligometastatic prostate cancer patients after SBRT,with median PSA-PFS of 12.3 months (range 1.2-58.3 months).PSA level increase was observed in 29 oligometastatic prostate cancer patients after SBRT.Six local recurrence were observed resulting in an actuarial 1-year,2-year and 3-year LCR of 90.4％,86.9％ and 82.6％,respectively.Twelve patients treated without ADT after SBRT,with median follow-up of 8.6 months (range 2.9-58.3 months) in this subgroup.Seven patients were added ADT after SBRT,with the median time from SBRT to initiation of ADT of 13.3 months (range 3.0-24.0 months) in this subgroup.Twelve patients were treated with ADT continuously after SBRT.Conclusions CyberKnife seems to be a safe and effective treatment with tolerated adverse events and good local control for patients with oligometastatic prostate cancer.
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Objective To determine the effectiveness and safety of patients treated with stereotactic body radiotherapy ( SBRT ) - CyberKnife for small hepatocellular carcinoma. Methods A prospective analysis of treatment details and outcomes for 33 patients with small hepatocellular carcinoma treated by CyberKnife at CyberKnife center of Shanghai Changhai Hospital from June 2014 to December 2016 was presented. Patients were followed every 3 months. WHO modified response evaluation criteria in solid Tumors( mRECIST) was used to evaluate efficacy, Common Terminology Criteria for Adverse Events Version 4. 0(CTCAE 4. 0) to evaluate treatment response, Kaplan-Meier method to calculate survival rate and local control rate and plot survival curves. Results There were 33 patients, 33 targets included in the study at the date of the last follow-up. 18 lesions (54. 5%) showed complete remission response, 7 lesions (21. 2%) showed partial remission response, 5 lesions (15. 2%) showed stable, and 3 lesions (9. 1%) progressed. Response rate was 75. 8%, and disease control rate was 90. 9%. 1- and 2-year local control rate was 100% and 83. 6%, respectively. The median disease progression free survival ( DPFS) was 15. 0 months. Non irradiated liver volume more than 100 ml, prior AFP less than 100 ng/ml, post-treatment CTCAE less than grade 2 could improve overall survival ( OS ) . V5 was a factor in grades 2 -4 hepatic toxicity ( P=0. 015 ) . All patients tolerated the radiosurgery, with grade 1 and grade 2 fatigue, and the gastrointestinal reactions and liver injury was the main side effect. 1 patient with grade 3 liver damage relieved at 6 months after treatment and 1 patient with grade 4 liver damage cured at 12 months after treatment. No grade 5 toxicity was encountered. Conclusions CyberKnife seems to be a safe and effective treatment measure with tolerated adverse reaction and good local control rate for patients with small hepatocellular carcinoma.
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Objective To explore the value of Multiple b value DWI ( MbDWI ) in the short-term efficacy evaluation of cyberknife radiotherapy for locally advanced pancreatic cancer ( LAPC ) .Methods A total of 36 patients underwent both conventional sequence and respiratory triggered MbDWI ( b=0, 25, 50, 75, 100, 150, 200, 400, 600, 800, 1 000 s/mm2 ) before cyberknife radiotherapy, 1month and 3 months after the radiotherapy, respectively.ADCtot, f, Dfast and Dslow were calculated using single and double exponential model and the changes before and after radiotherapy were observed.Results Before radiotherapy, 1 month and 3 months after radiotherapy, the ADCtot values of solid lesions were (1.56 ±0.29) ×10-3 mm2/s, (1.75 ±0.31) ×10 -3 mm2/s and (18.6 ± 0.46) ×10 -3 mm2/s;the values of Dslow were (1.10 ±0.73) × 10 -3 mm2/s, ( 1.19 ±0.97 ) ×10 -3 mm2/s and ( 1.49 ±04.6 ) ×10 -3 mm2 s/; the values of Dfast were (83 .33 ±62 .57) ×10 -3 mm2/s,(124.57 ±123.10) ×10 -3 mm2/s and (108.07 ±96 .67) ×10 -3 mm2 /s; f values were (26.81 ±23.74)%,(23.61 ±22.75)% and (21.34 ±15.36)%, respectively.ADCtot values 1 month and 3 months after treatment were significantly higher than those before treatment and Dslow 3 months post-treatment was higher than that before treatment, and the differences were statistically significant ( both P<0.05) and no other differences between two groups were significant.There were no statistical differences on Dfast and f before and after radiotherapy.Conc lusions ADCtot and Dslow both showed a significant growth trend after cyberknife radiotherapy.The advanced degree of parenchymal cystic in the targeted lesion could reflect the short-term efficacy of cyberknife treatment.