OBJECTIVE: To lay a foundation for formulating clinical evaluation and regulatory policies regarding radiotherapy equipment in China. METHODS: Comprehensive retrieval and comparison of the regulatory requirements for radiotherapy equipment from regulatory agencies in the United States, the European Union, and China are conducted, and their similarities and differences are analyzed. RESULTS: For mature radiotherapy systems in the European and American regions, the comparison of performance parameters serves as an important basis for determining whether a product can be marketed. Both the European Union and China regard the clinical evaluation report as a crucial part of the medical device review and submission process. CONCLUSION Identifying clear state of the art standards, performance parameters, and clinical indicator parameters, and establishing relevant technical guidelines are important directions for promoting the standardized development of radiotherapy equipment supervision.
Radiotherapy/standards* ; United States ; China ; European Union

OBJECTIVE: To compare the application among intensity-modulated radiotherapy (IMRT), three-dimensional conformal radiotherapy(3D-CRT) and conventional radiotherapy (CRT) for locally advanced middle-low rectal cancer. METHODS: From January 2015 to December 2016, 93 locally advanced middle-low rectal cancer patients with clinical stage cT3N+M0 or cT4N0/+M0 who underwent preoperative concurrent chemoradiotherapy at Department of Colorectal Surgery, the Third Affiliated Hospital of Kunming Medical University and had complete data were enrolled in this retrospective cohort study. Patients were divided into IMRT group (17 cases), 3D-CRT group (28 cases) and CRT group (48 cases) according to different radiotherapy methods. The frequency and dose of CRT were 1 time/day, 5 times/week, for a total of 5 weeks, with a single dose of 2.0 Gy, the total dose was 50 Gy. Frequency and dose of 3D-CRT and IMRT were 1 time/day, 5 times/week, for a total of 23 to 28 times, with a single dose of 1.8 to 2.0 Gy, and a total dose of 45.0 to 50.4 Gy. The chemotherapy regimen was performed with capecitabine tablets at a dose of 825 mg/m twice a day for 5 days every week, at the same time during radiotherapy. The efficacy, chemotherapy adverse reactions and immune function of the three groups were compared. RESULTS: There was no significant difference in the baseline data among the three groups (all P>0.05). The proportion of patients receiving permanent ostomy in the IMRT group and the 3D-CRT group was 29.4%(5/17) and 32.1%(9/28) respectively, which was lower than 58.3%(28/48) in CRT group, and the difference was statistically significant (χ²=7.982, P=0.030), while this proportion was not significantly different between IMRT and 3D-CRT group(χ²=0.037, P=0.848). The pathologic complete response(pCR) rate was 23.7%(22/93) in the whole study, and the pCR rate was 39.3%(11/28) in the 3D-CRT group, which was higher than that of CRT group and IMRT group [12.5%(6/48) and 29.4%(5/17)], and the difference was statistically significant (χ²=7.407, P=0.025), while there was no significant difference in pCR rate between CRT group and IMRT group (χ²=2.554, P=0.110). There was no adverse reaction of grade 3 or above in all three groups. No significant difference in the incidence of bone marrow suppression, abnormal liver and kidney function markers, digestive tract reaction or radiation dermatitis was found(all P>0.05). After receiving concurrent chemoradiotherapy, the proportion of CD3/CD4 cells in the IMRT group and the CRT group decreased compared with that before treatment(23.1±9.3 vs. 31.1±10.9, 27.4±10.7 vs. 33.6±7.2, respectively); the proportion of CD3/CD8 cells was up-regulated (36.1±15.2 vs. 24.8±10.9, 30.9±14.4 vs. 24.0±8.3,respectively), and the differences were statistically significant (both P<0.05), while the above indexes before and after treatment were not significantly different in the 3D-CRT group(all P>0.05). After treatment, the proportion of CD4/CD8 cells in IMRT group decreased (0.8±0.6 vs. 1.6±1.0, t=3.838, P=0.003), while this proportion was not significantly different in CRT group and 3D-CRT group(all P>0.05). CONCLUSIONS IMRT and 3D-CRT can reduce the rate of permanent stoma. 3D-CRT can increase pCR rate. No obvious advantage is shown in IMRT as compared with 3D-CRT in the short-term efficacy. On the contrary, an immunosuppressive status may occur. Therefore, 3D-CRT is recommended as the best preoperative treatment strategy for patients with locally advanced middle-low rectal cancer, especially for those with immunosuppression status.
Humans ; Radiotherapy ; methods ; standards ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; Radiotherapy, Conformal ; standards ; Radiotherapy, Intensity-Modulated ; standards ; Rectal Neoplasms ; radiotherapy ; Retrospective Studies

OBJECTIVE: To compare the accuracy of different methods for image registration in image-guided adaptive brachytherapy (IGABT) for cervical cancer. METHODS: The last treatment planning CT images (CT1) and the first treatment planning CT images (CT2) were acquired from 15 patients with cervical cancer and registered with different match image qualities (retained/removed catheter source in images) and different match regions [target only (S Group)/ interested organ structure (M Group)/body (L Group)] in Velocity3.2 software. The dice similarity coefficient (DSC) between the clinical target volumes (CTV) of the CT1 and CT2 images (CTVCT1 and CTVCT2, respectively) and between the organs-at-risk (OAR) of the two imaging datasets (OARCT1 and OARCT2, respectively) were used to evaluate the image registration accuracy. RESULTS: The auto-segmentation volume of the catheter source using Velocity software based on the CT threshold was the closest to the actual volume within the CT value range of 1700-1800 HU. In the retained group, the DSC for the OARs of was better than or equal to that of the removed group, and the DSC value of the rectum was significantly improved ( < 0.05). For comparison of different match regions, the high-risk target volume (HRCTV) and the low-risk target volume (IRCTV) had the best precision for registration of the target area, which was significantly greater than that of M group and L group ( < 0.05). The M group had better registration accuracy of the target area and the best accuracy for the OARs. The DSC values of the bladder and rectum were significantly better than those of the other two groups ( < 0.05). CONCLUSIONS The CT value range of 1700-1800 HU is optimal for automatic image segmentation using Velocity software. Automatic segmentation and shielding the volume of the catheter source can improve the image quality. We recommend the use of interested organ structures regions for image registration in image-guided adaptive brachytherapy for cervical cancer.
Brachytherapy ; methods ; standards ; Female ; Humans ; Organs at Risk ; diagnostic imaging ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; standards ; Radiotherapy, Image-Guided ; methods ; standards ; Software ; Tomography, X-Ray Computed ; methods ; standards ; Uterine Cervical Neoplasms ; diagnostic imaging ; radiotherapy

Nuclear medicine is a rapidly growing discipline that employs advanced novel hybrid techniques that provide unique anatomical and functional information, as well as targets for molecular therapy. Concomitantly, there has been an increase in the attention paid to medical radiation exposure. A radiological justification for the practice of nuclear medicine has been implemented mainly through referral guidelines based on research results such as prospective randomized clinical trials. The International Commission on Radiological Protection recommends diagnostic reference levels as a practical mechanism to optimize medical radiation exposure in order to be commensurate with the medical purpose. The Korean Society of Nuclear Medicine has been implementing radiological optimization through a survey of the protocols on how each hospital determines the dose of administration of each radiopharmaceutical. In the case of nuclear medicine, radiation exposure of caregivers and comforters of patients discharged after administration of therapeutic radiopharmaceuticals can occur; therefore, optimization has been implemented through written instructions for patients, based on international recommendations. The development of patient-radiation-dose monitoring software, and a national registry and management system of patient-radiation-dose is needed to implement radiological optimization through diagnostic reference levels. This management system must work in agreement with the "Institute for Quality Management of Nuclear Medicine", and must take into account the medical reality of Korea, such as low medicine fee, in order to implement reasonable radiological justification and optimization.
Humans ; Neoplasms/diagnosis/radiotherapy ; Positron-Emission Tomography ; *Practice Guidelines as Topic ; Radiation Exposure/*standards ; Radiation Protection ; Radiopharmaceuticals/chemistry/therapeutic use ; Reference Values ; Republic of Korea ; Societies, Scientific ; Tomography, X-Ray Computed

After the rapid development of medical equipment including CT or PET-CT, radiation doses from medical exposure are now the largest source of man-made radiation exposure. General principles of radiation protection from the hazard of ionizing radiation are summarized as three key words; justification, optimization, and dose limit. Because medical exposure of radiation has unique considerations, diagnostic reference level is generally used as a reference value, instead of dose limits. In Korea, medical radiation exposure has increased rapidly. For medical radiation exposure control, Korea has two separate control systems. Regulation is essential to control medical radiation exposure. Physicians and radiologists must be aware of the radiation risks and benefits associated with medical exposure, and understand and implement the principles of radiation protection for patients. The education of the referring physicians and radiologists is also important.
Guidelines as Topic ; Humans ; International Agencies ; *Occupational Exposure ; Positron-Emission Tomography ; Radiation Injuries/etiology/prevention & control ; *Radiation Protection ; Radiation, Ionizing ; Radiotherapy Dosage/standards ; Reference Values ; Tomography, X-Ray Computed

Electronic medical records (EMR) is the clinical diagnosis, guiding intervention and digital medical service record of outpatient, hospital patients (or care object) in medical institution. And it is the complete, detailed clinical information resource which has produced and recorded in all previous medical treatments. Radiotherapy electronic medical records contain texts, images and graphics, therefore the information is more complicated. This paper proposes an EMR information system based on DICOM-RT standard, through the use of seven objects of DICOM-RT to achieve the information exchange and sharing between different systems, equipments, convenient radiotherapy treatment data management, improve the efficiency of radiation treatment.
Computer Communication Networks ; Humans ; Medical Records Systems, Computerized ; standards ; Radiographic Image Enhancement ; methods ; Radiology Information Systems ; organization & administration ; Radiotherapy, Computer-Assisted ; methods ; User-Computer Interface

OBJECTIVETo study the impact of different planning target volume (PTV) margin settings on surface and superficial dose distribution and explore the resolution of high superficial dose when the target area is close to the surface during head and neck intensity-modulated radiotherapy (IMRT).

METHODSA typical superficial target volume was designed in an circular neck phantom. Two experimental inverse IMRT plans were conducted with 8MV X ray, and in plan A, the superficial side of PTV margin ranged from 0 to 5 mm, while other side margins were 5 mm; in plan B, an suppositional machine dosimetry data for IMRT optimization was established in which the build-up dose was eliminated, and this machine data was used to optimize the inverse IMRT plan followed by recalculation of the planned dose distribution with the actual clinical machine dosimetry data. The variation of the surface and superficial dose resulting from set-up error and the dose distribution to CTV were compared. The adequate PTV margin was analyzed when the CTV approached the surface.

RESULTSIn plan A, the high dose greater than the prescribed dose was found in the surface and superficial region when the superficial sparing distance was between the surface and PTV d<3 mm, and the 3 mm set-up margin increased this superficial dose remarkably. Reducing the superficial side of PTV margin lowered the high superficial dose effectively and allowed maintenance of the prescribed dose to the CTV. To avoid reduction of the dose to the CTV to below 95% of the prescribed dose, the superficial side of PTV margin should be greater than 1 mm. Plan B effectively lowered the surface doses and maintained the prescribed dose to the CTV.

CONCLUSIONSWith appropriate techniques for optimizing inverse IMRT, more homogeneous superficial dose can be achieved.

Computer Simulation ; Head and Neck Neoplasms ; radiotherapy ; Humans ; Radiation Injuries ; prevention & control ; Radiation Protection ; methods ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy, Intensity-Modulated ; methods ; standards ; Skin ; radiation effects

Quality control includes application of VARIAN IMRT network, quality control of radiotherapy technology, radiologic physics and radiotherapy equipment. Strengthen quality control and establish quality control system can further promote the level of intensity modulation radiotherapy.
Quality Control ; Radiotherapy, Intensity-Modulated ; standards

As a powerful global optimization approach, genetic algorithms (GA) can solve a variety of optimization problems in which the objective function is discontinuous, non-differentiable, or highly non-linear, to produce high convergence speed and vast search space. In this thesis, GA is used to optimize the beam weights of intensity modulated radiation therapy (IMRT) inverse planning, and 2D and 3D isodose contour as well as dose volume histogram (DVH) are used to evaluate the treatment plan. Also presented in this thesis are the results of calculation with discussions.
Algorithms ; Humans ; Models, Theoretical ; Radiotherapy Dosage ; Radiotherapy Planning, Computer-Assisted ; methods ; Radiotherapy, Conformal ; methods ; standards

INTRODUCTIONThis study aims to assess the early tumour outcome and morbidity associated with radiation therapy (RT) in tumours of the central nervous system (CNS).

MATERIALS AND METHODSPatients receiving RT with radical intent were entered on a prospective database. Tumour types were categorised into glioma, base of skull, pituitary, germ cell or primitive neuroectodermal tumour (PNET) and other malignant CNS tumours. Study endpoints were overall survival and progression free survival. Acute and late toxicity endpoints included Common Terminology Criteria version 3.0 (CTC) grade 3 or 4 events, need for admission during RT and change in performance status at 12 months.

RESULTSOne hundred and fifty-two patients with CNS tumours were managed with radical intent over the 4-year period. The median age was 49 years and 68.4% were Eastern Co-operative Group (ECOG) 0-1 performance status. The major pathology groups were glioma (59.9%) and base of skull tumours (17.1%). Gross total resection was performed in 28.3% only and RT was delayed after diagnosis until time of progression in 19.7%. For the 91 patients with glioma, the median survival and 2-year survival rate was 19.1 months and 44.1%, respectively. The 2-year survival rates for the subgroups of WHO Grade I or II, III and IV were 100%, 52% and 35%, respectively. For the non-glioma tumour groups, the relapse varied with pathology. Toxicity was minimal with only 3 acute and 3 late CTC grade 3 or 4 events occurring. Overall, 47 or 31% of patients required some inpatient hospitalisation during RT, although this was determined to have some causative relationship to RT in only 12 or 8% of patients. In the 12 months post-RT, performance status was stable or improved in 76.2% of patients, and most deterioration was associated with tumour relapse.

CONCLUSIONSRT for CNS tumours using modern techniques was well-tolerated with good tumour outcome and minimal morbidity.

Adolescent ; Adult ; Aged ; Central Nervous System ; physiopathology ; Central Nervous System Neoplasms ; radiotherapy ; Child ; Child, Preschool ; Female ; Humans ; Male ; Middle Aged ; Prospective Studies ; Radiotherapy ; methods ; standards ; Singapore ; Survival Analysis