ABSTRACT
OBJECTIVE@#To identify the problems in clinical radiotherapy planning for cervical cancer through quantitative evaluation of the radiotherapy plans to improve the quality of the plans and the radiotherapy process.@*METHODS@#We selected the clinically approved and administered radiotherapy plans for 227 cervical cancer patients undergoing external radiotherapy at Sun Yat-sen University Cancer Center from May, 2019 to January, 2022. These plans were transferred from the treatment planning system to the Plan IQTM workstation. The plan quality metrics were determined based on the guidelines of ICRU83 report, the GEC-ESTRO Working Group, and the clinical requirements of our center and were approved by a senior clinician. The problems in the radiotherapy plans were summarized and documented, and those with low scores were re-planned and the differences were analyzed.@*RESULTS@#We identified several problems in the 277 plans by quantitative evaluation. Inappropriate target volume selection (with scores < 60) in terms of GTV, PGTV (CI) and PGTV (V66 Gy) was found in 10.6%, 65.2%, and 1% of the plans, respectively; and the PGTV (CI), GTV, and PCTV (D98%, HI) had a score of 0 in 0.4%, 10.1%, 0.4%, 0.4% of the plans, respectively. The problems in the organs at risk (OARs) involved mainly the intestines (the rectum, small intestine, and colon), found in 20.7% of the plans, and in occasional cases, the rectum, small intestine, colon, kidney, and the femoral head had a score of 0. Senior planners showed significantly better performance than junior planners in PGTV (V60 Gy, D98%), PCTV (CI), and CTV (D98%) (P≤0.046) especially in terms of spinal cord and small intestine protection (P≤0.034). The bowel (the rectum, small intestine and colon) dose was significantly lower in the prone plans than supine plans (P < 0.05), and targets coverage all met clinical requirements. Twenty radiotherapy plans with low scores were selected for re-planning. The re-planned plans had significantly higher GTV (Dmin) and PTV (V45 Gy, D98%) (P < 0.05) with significantly reduced doses of the small intestines (V40 Gy vs V30 Gy), the colon (V40 Gy vs V30 Gy), and the bladder (D35%) (P < 0.05).@*CONCLUSION@#Quantitative evaluation of the radiotherapy plans can not only improve the quality of radiotherapy plan, but also facilitate risk management of the radiotherapy process.
Subject(s)
Humans , Female , Uterine Cervical Neoplasms/radiotherapy , Rectum , Colon , Kidney , Organs at RiskABSTRACT
Objective To develop a MOSAIQ Integration PlatformCHN (MIP) based on the workflow of radiotherapy (RT) and to meet the actual requirements in China and the special needs for the radiotherapy department.Methods MIP used C/S (client-server) structure mode running on the local network in the hospital and its database was based on the Treatment Planning System (TPS) and MOSAIQ database.Five network servers,as the core hardware,supplied data storage and network service based on cloud services.The core software was developed based on Microsoft Visual Studio Platform using C# network programming language.The MIP server could simultaneously offer network service for about 200 workstations,including entry,query,statistics,and print of data.Results MIP had 15 core function modules,such as Notice,Appointment,Billing,Document Management (application/execution),and System Management,which almost covered the whole workflow of radiotherapy.Up to June 2016,the recorded data in the MIP were as follows:13546 patients,13533 plan application forms,15475 RT records,14656 RT summaries,567048 billing records,and 506612 workload records.Conclusions The MIP based on the RT workflow has been successfully developed and used in clinical practice.It is an important part of radiotherapy information system construction with the advantages of intuitive operation,real-time performance,data security,and stable operation.It is digital,paperless,user-friendly,and convenient for the retrieval and statistics of data as well as information sharing and department management,and can significantly improve the efficiency of the department.More functions can be added or modified to enhance its potentials in research and clinical practice.
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 dosimetric characteristics and their clinical applications of volumetric modulated Arc therapy (RapidArc) with fixed-fields intensity modulated radiotherapy for early stage nasal NK/T-cell lymphoma.Methods Ten patients with stage Ⅰ E and Ⅱ E nasal NK/T-cell lymphoma were enrolled in the study.Five field coplanar plan (5F),nine field coplanar plan (9F),five field non-coplanar plan (5F-N) and RapidArc plans were designed for each patient,in which 5F plan was set as the control group.Conformity index (CI) and homogeneity index (HI) as well as the maximum dose of organs at risks were compared.Results The target CI of 5F,9F,5F-N and RapidArc plan was 0.419±0.159,0.478 ±0.181,0.465 ±0.121 and 0.518 ±0.111,respectively.Compared with 5F (0.136±0.038),the target HI of 9F and RapidArc plan was 0.111 ±0.027 and 0.112 ±0.031 (t =3.11,3.04,P ＜ 0.05).9F plan significantly increased the Dmax of lens in the contralateral side(t =2.82,P ＜ 0.05) and in ipsilateral side (t =3.25,P ＜ 0.05),while 5F-N plan decreased the Dmax of optical nerves by up to 9％.RapidArc plan effectively reduced the radiation to organs at risk in lens (t =3.25,P ＜0.05),eyes (t =3.25,P ＜0.05),optical nerve (t =2.57,P ＜0.05) and optical chaism(t =7.62,P ＜0.05).The delivery efficiency of four plans ranked as RapidArc ＞ 5F ＞ 5F-N ＞ 9F.Conclusions RapidArc produced statistically significant improvement in the dose distributions of targets,and also reduced the Dmax of organs at risk,which would be the better choice of radiotherapy for nasal NK/T-cell lymphoma.
ABSTRACT
Objective To evaluate the accuracy of image registration based on bony structure (RBS) and grey-scale (RGS) in positioning correction of radiation treatment,and their reliability in clinical application.Methods Setup errors of anthropomorphic phantom (chest& abdomen,head& neck) were simulated with x-,y-,z-directions.CBCT images were acquired for each simulation and registered with planning CT.using bony structure and grey-scale registration separately.Geometry accuracy of all registration were then obtained and analyzed.Results The errors of RBS and RGS in x-,y-,z-directions were (-0.65 ±0.22) mm and (-0.70±0.17) mm (P=0.00),(1.02 ±0.27) mm and (0.90±0.20) mm (P =0.00),(1.46 ± 0.53) mm and (1.47 ± 0.47) mm (P =0.54) for head& neck positioning; with (0.82±0.33) mm and (0.79±0.18) mm (P=0.03),(2.45±1.17) mm and (1.61 ±0.84) mm (P =0.00),(1.44 ± 3.25) mm and (0.19 ± 1.11) mm (P =0.00) for chest& abdomen positioning.Conclusions RGS is more accurate and stable than RBS.The accuracy of image registration is a little better for head& neck than that for chest& abdomen.The algorithms of image registration used in clinical application needs to be tested independently and the systematic error needs to be corrected before applying in different treatment techniques according to their accuracy requirement.
ABSTRACT
To synchronize the radiation of microSelectron-HDR (Nucletron afterloading machine) and measurement of MOSFET dose system, a trigger system based on interface circuit was designed and corresponding monitor and trigger program were developed on Qt platform. This interface and control system was tested and showed stable operate and reliable work. This adopted serial port detect technique may expand to trigger application of other medical devices.