Objective To evaluate the quality of treatment planning(TP)and re-optimization planning(RP)of radiotherapy for rectal cancer using PlanIQ software,thereby providing methods and tools for the screening and optimization of radiotherapy plans.Methods Twenty patients with rectal cancer who received radiotherapy were selected retrospectively,with 10 cases of intensity-modulated radiotherapy(IMRT)and 10 of volumetric modulated arc therapy(VMAT).(1)TP:IMRT plan involved 5-field irradiation,and VMAT plan involved two 360°arcs.The prescription doses were 50 Gy/25 f for PTV1 and 45 Gy/25 f for PTV2.All plans underwent direct machine parameter optimization and required 95%isodose lines to cover 100%of the target volume.Organs-at-risk(OAR)were limited by reference to tolerated dose standards.After the planning was completed,the plans were reviewed and confirmed by a physician,and the treatment was implemented after dose verification.(2)RP:a physicist with 10 years of experience re-optimized the 20 TP plans,with the irradiation technique and field setting unchanged.The re-optimization involved adjusting planning conditions and parameters based on individual experience until the dose to OAR was minimized while without affecting PTV coverage.The quality of TP plans and RP plans were quantitatively evaluated using PlanIQ software.Non-parametric Wilcoxon signed rank test was performed for dose-volume histogram parameters and plan quality index between two groups.Results The dose-volume histogram parameters in RP plans were superior to those in TP plans,and the differences in the Dmax of PTV1,the V45 Gy and Dmax of small intestine,and the V45 Gy of colon were statistically significant(P<0.05).The quality scores of RP plans for IMRT group,VMAT group and all patients were significantly higher than those of TP plans(P<0.05),with plan quality index of 88.55±3.35 vs 86.61±4.63(P=0.005),89.72±3.15 vs 87.21±3.04(P=0.028),and 89.14±3.22 vs 86.91±3.22(P=0.001),respectively.Conclusion RP can further improve the quality of radiotherapy plan for rectal cancer.PlanIQ software serves as an effective tool for quality control and screening of radiotherapy planning.

Objective To assess inter-observer variations(IOV)in the delineation of target volumes and organs-at-risk(OAR)for intensity-modulated radiotherapy(IMRT)of nasopharyngeal carcinoma(NPC)among physicians from different levels of cancer centers,thereby providing a reference for quality control in multi-center clinical trials.Methods Twelve patients with NPC of different TMN stages were randomly selected.Three physicians from the same municipal cancer center manually delineated the target volume(GTVnx)and OAR for each patient.The manually modified and confirmed target volume(GTVnx)and OAR delineation structures by radiotherapy experts from the regional cancer center were used as the standard delineation.The absolute volume difference ratio(△V_diff),maximum/minimum volume ratio(MMR),coefficient of variation(CV),and Dice similarity coefficient(DSC)were used to compare the differences in organ delineation among physicians from different levels of cancer centers and among the 3 physicians from the same municipal cancer center.Furthermore,the IOV of GTVnx and OAR among physicians from different levels cancer centers were compared across different TMN stages.Results Significant differences in the delineation of GTVnx were observed among physicians from different levels of cancer centers.Among the 3 physicians,the maximum values of △V_diff,MMR,and CV were 97.23%±83.45%,2.19±0.75,and 0.31±0.14,respectively,with an average DSC of less than 0.7.Additionally,there were considerable differences in the delineation of small-volume OAR such as the left and right optic nerves,chiasm,and pituitary,with average MMR>2.8,CV>0.37,and DSC<0.51.However,relatively smaller differences were observed in the delineation of large-volume OAR such as the brainstem,spinal cord,left and right eyeballs,and left and right mandible,with average△V_diff<42%,MMR<1.55,and DSC>0.7.Compared with the differences among physicians from different levels cancer centers,the differences among the 3 physicians from the municipal cancer center were slightly reduced.Furthermore,there were also differences in the delineation of target volumes for NPC among physicians from different levels cancer centers,depending on the staging of the disease.Compared with the delineation of target volumes for earlier stage patients(stages I or II),the differences among physicians in the delineation of target volumes for advanced stage patients(stages III or IV)were smaller,with average △V_diff and DSC of 98.31%±67.36%vs 69.38%±72.61%(P<0.05)and 0.55±0.08 vs 0.72±0.12(P<0.05),respectively.Conclusion There are differences in the delineation of GTVnx and OAR in radiation therapy for NPC among physicians from different levels of cancer centers,especially in the delineation of target volume(GTVnx)and small-volume OAR for early-stage patients.To ensure the accuracy of multicenter clinical trials,it is recommended to provide unified training to physicians from different levels of cancer centers and review their delineation results to reduce the effect of differences on treatment outcomes.

Female ; Humans ; Pregnancy ; Septate Uterus ; Uterus/surgery* ; Hysteroscopy/methods* ; Estrogens ; Tissue Adhesions/surgery* ; Randomized Controlled Trials as Topic ; Multicenter Studies as Topic

In recent years, ultra-high dose rate (FLASH) radiotherapy has become one of the most advanced research topics in the field of radiotherapy. Experimental data indicate that FLASH radiotherapy can significantly reduce the irradiation damage in normal tissues while being as effective as clinical conventional dose rate radiotherapy in tumor control. The oxygen depletion hypothesis is considered as one of the key mechanisms underlying the FLASH effect. In this article, research progress on the discovery, experimental evidence and reaction principle of oxygen depletion was reviewed, the measurement methods and biological effect modeling methods of the oxygen depletion hypothesis were summarized, and the oxygen depletion difference between normal tissue and tumor was also discussed.

Purpose: This study was aimed to investigate long-term survivals and toxicities of early-stage nasopharyngeal carcinoma (NPC) in endemic area, evaluating the role of chemotherapy in stage II patients. Materials and Methods: Totally 187 patients with newly diagnosed NPC and restaged American Joint Committee on Cancer/ International Union Against Cancer 8th T1-2N0-1M0 were retrospectively recruited. All received intensity-modulated radiotherapy (IMRT)±chemotherapy (CT) from 2001 to 2010. Results: With 15.7-year median follow-up, 10-year locoregional recurrence-free survival, distant metastasis-free survival (DMFS), disease-specific survival (DSS), and overall survival (OS) were 93.3%, 93.5%, 92.9% and 88.2%, respectively. Multivariable analyses showed cervical lymph nodes positive and pre-treatment prognostic nutritional index ≥ 52.0 could independently predict DMFS (p=0.036 and p=0.011), DSS (p=0.014 and p=0.026), and OS (p=0.002 and p < 0.001); Charlson comorbidity index < 3 points could predict DSS (p=0.011); age > 45 years (p=0.002) and pre-treatment lactate dehydrogenase ≥ 240 U/L (p < 0.001) predicted OS. No grade 4 late toxicity happened; grade 3 late toxicities included subcutaneous fibrosis (4.3%), deafness or otitis (4.8%), skin dystrophy (2.1%), and xerostomia (1.1%). No differences on survivals were shown between IMRT+CT vs. IMRT alone in stage II patients, even in T2N1M0 (p > 0.05). Unsurprising, patients in IMRT+CT had more acute gastrointestinal reaction, myelosuppression, mucositis, late ear toxicity, and cranial nerve injury (all p < 0.05) than IMRT alone group. Conclusion Superior tumor control and satisfying long-term outcomes could be achieved with IMRT in early-stage NPC with mild late toxicities. As CT would bring more toxicities, it should be carefully performed to stage II patients.

Objective: To assess the interobserver variations in delineating the planning target volume (PTV) and organs at risk (OAR) using different contouring methods during intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC), aiming to provide references for the quality control of multi-center clinical trials. Methods: The PTV and OAR of CT image of 1 NPC patient manually delineated by 10 physicians from 8 different radiation centers were defined as the " manual contour group" , and the OAR auto-contoured using the ABAS software and modified by the physicians were defined as the " auto+ manual contour group" . The maximum/minimum ratio (MMR) of the PTV and OAR volumes, and the coefficient of variation (CV) for different delineated contours were comparatively evaluated. Results: Large variation was observed in the PTV and OAR volumes in the manual contour group. The MMR and CV of the PTV were 1.72-3.41 and 0.16-0.39, with the most significant variation in the PTV_nd (MMR=3.41 and CV=0.39 for the PTV_nd-L). The MMR and CV of the manually contoured OAR were 1.30-7.89 and 0.07-0.67. The MMR of the temporal lobe, spinal cord, temporomandibular joint, optic nerve and pituitary gland exceeded 2.0. Compared with the manual contour group, the average contouring time in the auto+ manual group was shortened by 68% and the interobserver variation of the OAR volume was reduced with an MMR of 1.04-2.44 and CV of 0.01-0.37. Conclusions Large variation may occur in the PTV and OAR contours during IMRT plans for NPC delineated by different clinicians from multiple medical centers. Auto-contouring+ manually modification can reduce the interobserver variation of OAR delineation, whereas the variation in the delineation of small organs remains above 1.5 times. The consistency of the PTV and OAR delineation and the possible impact upon clinical outcomes should be reviewed and evaluated in multi-center clinical trials.

Objective To investigate the physics technique and quality assurance (QA) during radiotherapy in the institutions from the East Guangdong province,aiming to provide reference for the construction of radiotherapy discipline and rational allocation of resources in the primary hospitals from the eastern Guangdong province.Methods From March 15 to May 20,2016,the general conditions,radiotherapy equipment,available technique and quality assurance (QA) in the medical institutions from eastern Guangdong were investigated and analyzed by online combined with on-spot surgery.Results There were 8 institutions which provided radiotherapy with 966 ward beds,a daily capacity of 632 patients and 222 radiotherapy practitioners.Radiotherapy equipment included 12 linear accelerators,5 after-loading devices,1γ-knife,8 CT simulators and 9 radiotherapy planning systems.Five institutions performed IMRT/VMAT,IGRT and ART.Dose verification was performed before precision radiotherapy delivery in all institutions except for 1 center.QA procedures were missing for the linear accelerators,CT simulators and after-loading devices.Short-term advanced studies and hand-by-hand teaching were the main approaches for staff professional training.Conclusions The resource allocation for radiotherapy in the medical centers from the eastern Guangdong province is scarce.The technique and QC levels greatly differ among different institutions.Standard QA protocols are urgently to be established and implemented.Extensive attentions should be paid to the the professional training for technicians.

Objective To analyze the 10-year survival outcome and failure patterns for patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT),aiming to provide reference for optimized treatment for NPC.Methods Clinical data of 866 patients with NPC receiving IMRT from January 2001 to December 2008 were retrospectively analyzed.Survival analysis was performed using the Kaplan-Meier estimator.Univariate analysis was carried out by log-rank test and multivariate analysis was performed using Cox proportional hazards model.Results The median follow-up time was 132 months.The 10-year local recurrence-free survival (LRFS),distant metastasis-free survival (DMFS),progression-free survival (PFS) and disease specific survival (DSS) were 92.0％,83.4％,75.7％ and 78.6％,respectively.A total of 210 patients died including 124 patients (59.0％) from distant metastasis,which was the primary cause of death,and 47 (22.3％) from local regional recurrence.Independent negative factors of DSS included age＞50 years (P=0.00),LDH ≥ 245 IU/L (P=0.00),Hb＜ 120 g/L (P=0.01),T2-T4 staging (P=0.00),N1-N3 staging (P=0.00) and GTV-nx＞20 cm3(P=0.00).The 10-year LRFS,DMFS and DSS of stage Ⅱ NPC patients did not significantly differ after IMRT alone and chemoradiotherapy (P=0.83,0.22,0.23).For patients with stage Ⅲ NPC,the 10-year LRFS and DSS in the chemoradiotherapy arm were significantly higher than those in the IMRT alone (P=0.01,0.01),whereas no statistical significance was observed in the DMFS between two groups (P=0.14).The overall survival of stage Ⅳa+Ⅳb NPC patients is relatively poor.Conclusions IMRT can improve the long-term survival of NPC patients.Distant metastasis is the primary failure pattern.Patients with stage Ⅰ-Ⅱ NPC can obtain satisfactory survival outcomes after IMRT alone.The addition of chemotherapy can further enhance the LRFS and DSS of stage Ⅲ NPC patients.However,the optimal therapeutic strategy remains to be urgently investigated for stage a+ Ⅳb NPC patients.

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.

Objective To conduct the 7th investigation by Chinese Society of Radiation Oncology,Chinese Medical Association,and to further investigate the current situation of radiotherapy in mainland China,reasonably allocate personnel and equipment resources,and promote the development of radiotherapy in China.Methods From October 8,2015 to December 2015,the office for investigation of radiotherapy information was established,the list and contact information of radiotherapy units were provided by each province,and a special data submission system was used for a complete,rapid,and efficient investigation through the Internet.Results As of January 20,2016,there were 1 413 radiotherapy units in the mainland China with 52,496 employees in total,among which there were 15 839 radiotherapy physicians (4824 with senior professional titles),8 452 technical therapists (260 with senior professional titles),3 292 physicists (562 with senior professional titles),and 938 maintenance engineers (120 with senior professional titles).In the aspect of radiotherapy equipment,there were 1930 linear accelerators,96 Co-60 teletherapy units,173 X-knife units,212 γ-knife units,382 Ir-192 brachytherapy units,436 Co-60 brachytherapy units,1 051 X-ray simulators,1 353 CT simulators,642 MRI simulators,978 sets of multileaf collimators,1922 sets of treatment planning systems,and 974 sets of radiotherapy network systems.As for quality control devices,there were 1 792 dosimeters,2 143 ionization chambers,935 two-dimensional array dosimeters,540 threedimensional dosimetric verification systems,596 three-dimensional water tanks,844 anthropomorphic phantoms,and 1 168 water equivalent phantoms.In the aspect of therapeutic situation,there were 102,170 beds (including beds in departments of oncology in general hospitals),76612 episodes per day,and 919339 episodes per year.Conclusions The results of this investigation show significant increases in radiotherapy units,personnel,and equipment in recent years in mainland China.The distribution of radiotherapy units and equipment and the structure of radiotherapy personnel are becoming more reasonable,but there are still some problems.In some regions,current radiotherapy equipment cannot meet the medical needs,and there is a lack of professional technical personnel.