ABSTRACT
Objective:To evaluate the preliminary clinical efficacy and safety of stereotactic body radiation therapy (SBRT) in combination with targeted therapy for metastatic renal cell carcinoma (mRCC).Methods:Clinical data of 58 patients with mRCC who were treated with SBRT in combination with targeted therapy in Sun Yat-sen University Cancer Center from June 2013 to December 2018 were retrospectively analyzed. Among them, 79.3% patients were classified as intermediate or high risk according to International Metastatic Renal Cell Carcinoma Database Consortium Criteria. The median biologically equivalent dose (BED) was 147 Gy (67 to 238 Gy).Results:Overall, 32, 13, 7, 5 and 1 patients received SBRT for 1, 2, 3, 4 and 6 metastatic sites (105 lesions) and 71.4% of them were bone lesions. Targeted therapy was continued during SBRT. With a median follow-up of 9.4 months (range 2.7 to 40.1 months), 18 patients died. The 1-year local control rate was 97.4%. The 1-year progression-free survival was 50.3%. The 1-and 2-year overall survival was 72% and 53%. Approximately 85% patients experienced pain relief after SBRT. Patients who achieved complete or partial response after SBRT obtained better overall survival than those with stable disease or disease progression (1-year overall survival: 83% vs. 48%, P=0.021). In the whole cohort, 6 cases developed Grade Ⅲ adverse events, 4 of which were Grade Ⅲ myelosuppression, 1 case of Grade Ⅲ neuropathy and 1 case of radiation-induced skin injury. Conclusion:Preliminary study reveals that combined use of targeted therapy and SBRT is an efficacious and safe treatment of advanced mRCC.
ABSTRACT
Objective To establish a quantitative evaluation of quality control image for the onboard imaging system of medical linear accelerator.Methods An MV planar image of electronic portal imaging device (EPID) is acquired by both Elekta iViewGT and Varian aS1000,and a kV planar image and cone-beam computed tomography (CBCT) images of CBCT are acquired by both Elekta X-ray volume imaging (XVI) and Varian On-board Imager (OBI).Phantoms used here included Las Vegas,TOR18FG,and Catphan504.A series of image quality indicators were evaluated by analyzing the images mentioned above using a quantitative method.Results A quantitative value was calculated to represent the contrast resolution of EPID.A modulation transfer function (MTF) to describe spatial resolution and a quantitative value representing contrast resolution were calculated for the kV planar image.As for the CBCT system,a series of quantitative results of noise,uniformity,CT value accuracy,and contrast resolution and a MTF were calculated to represent the performance of CBCT system.Conclusions Based on common phantoms,a complete set of quantitative methods to evaluate the image quality of EPID and CBCT has been developed,which could provide a very good reference for the establishment of quality control system for image-guided radiotherapy.
ABSTRACT
Objective To analyse the influencing factors diagnosed by the virtual touch tissue quantification (VTQ) technology on the hardness of papillary thyroid carcinoma (PTC).Methods From May 2011 to March 2014,a total of 266 PTCs in 266 patients confirmed by pathology were enrolled in Shanghai Tenth People's Hospital.The shear wave velocity (SWV) values of PTCs were measured by VTQ.PTCs were divided into 2 groups including SWV ≥ 2.87 rn/s and SWV ＜ 2.87 rn/s.The x2 test was used to compare the basic clinical data,ultrasound features and immunohistochemical results between 2 groups.The influencing factors of SWV values of PTCs were analyzed by forward stepwise Logistic regression analysis.Results Of the 266 PTCs,183 were SWV ≥ 2.87 m/s and 83 were SWV ＜ 2.87 m/s.The x2 test showed that the ultrasound features of PTCs such as single or multiple,with or without central lymph node metastasis,location,size,shape,with or without posterior acoustic attenuation,with or without calcification,with or without capsule invasion,whether close to the trachea between the 2 groups were significant different (x2=4.233,4.740,9.910,4.988,4.416,4.737,7.154,8.559,all P ＜ 0.05 or 0.01).Logistic regression analysis demonstrated that nodules were single or multiple,location,with or without posterior acoustic attenuation,with or without calcification,whether close to the trachea were influencing factors of SWV value of PTCs.The regression equation was defined as Y=-2.507 + 0.670X1 (nodules were single or multiple) + 0.800X3 (location of nodules) + 0.851X6 (with or without posterior acoustic attenuation) + 0.628X7 (with or without calcification) + 1.106X9 (whether close to the trachea).Conclusions Multiple nodules,central lymph node metastasis,located isthmus,nodules size ＞ 10 mm,irregular shape,posterior acoustic attenuation,calcification,capsule invasion,close to the trachea were correlated with the diagnosis of PTC by VTQ technology.The more characteristics of nodules appeared,such as multiple nodules,located isthmus,posterior acoustic attenuation,calcification,close to the trachea,the harder PTCs were.
ABSTRACT
Objective To study the mathematical predicting model of parotid DVH for the NPC IMRT planning, and its accuracy with the analysis of medical data. Methods 50 NPC radiotherapy treatment plans with same beam setup were chosen as sample data set, then their parotid DVHs and distance of voxels in the parotid to the target volumes were calculated with self-developed program to form the distance to target histogram ( DTHs);principal component analysis was applied to DVHs and DTHs to acquire their principal components ( PCs) ,and then nonlinear multiple variable regression was used to model correlation between the DTHs' PCs, parotids volume, PTVs and the DVHs. Another 10 plans were chosen as test data set to evaluate the efficacy and accuracy of the final model by comparing the DVHs calculated from our model with those calculated from the TPS. Results Up to 97% information of DTHs and DVHs can be represented with 2 to 3 components, the average fitting error of sample data set was (0±3. 5)%;in the 10 test cases, the shapes of DVH curves calculated from predicting model was highly the same with those from the TPS, the average modeling error was (-0.7± 4. 4)%,the accuracy of prediction was up 95%. Conclusions Our developed model can be used as a quality evaluating tool to predict and assure the dose distribution in parotid of NPC radiotherapy treatment planning effectively and accurately.
ABSTRACT
Objective To investigate the γ pass rate and contributing factors by summarizing the plan verification results of 260 volumetric modulated arc therapy (VMAT) plans.Methods From 2010 to 2012,two different detector arrays (MapCheck2,Sun,Nuclear,USA ; Delta4 ScandiDos,Swenden) were used for plan verification in 260 patients.The measured dose distributions were compared with the calculation results of treatment planning system using γ pass rate (Pγ ≤ 1 for 2％/2 mm,3％/3 mm and 5％/3 mm,threshold 10％).And the results were put under independent-samples t test.The impact of multi-leaf collimator (MLC) on the γ pass rate (3％/3 mm) was analyzed.Results The average γ pass rates of 2％/2 mm,3％/3 mm and 5％/3 mm of 260 VMAT plans were 91.7％,98.5％ and 99.7％,respectively.Among 260 VMAT plans,3 VMAT plans (1.2％ of the total) failed to meet the clinical acceptable pass rate and needed to be redesigned or re-optimized.The γ pass rate of 2％/2 mm was slightly different between two measurement devices (90.0％ vs 93.5％,P =0.000),while the γ pass rate of 3％/3 mm showed no significant difference between two measurement devices and two accelerators (98.5％ vs 98.5％,P =0.926 and 98.5％ vs 98.6％,P =0.670).The γ pass rate (3％/3 mm) of the treatment plan before MLC calibration was 61.1％,compared to 94.1％ after calibration.Conclusions Most dose verification results of treatment plans can meet the clinical requirement.Gantry rotation may influence the γ pass rate of VMAT dose verification under stricter pass rate standard (2％/2 mm).MLC calibration is essential for VMAT.