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Introduction: The complexity of the vocal phenomenon hinders the therapist's ability to quickly and effectively monitor the achievements obtained by the patient through vocal intervention. The assessment of therapeutic progress relies on the therapist's capability to utilize valid, reliable, and meaningful outcome criteria. Aim: Develop a conceptual framework of outcome criteria to be used in the treatment plans designed by speech-language pathologists for patients with vocal complaints. Methodology: Qualitative, conceptual, and model-type research in which a critical review is conducted through a non-probabilistic theoretical sampling of the theoretical models of therapy treatment plans, the outcome criteria involved and their relevance to voice intervention. Building upon this, a taxonomy of outcome criteria is proposed for verifying therapeutic progress in voice therapy. Results: A conceptual outcome criteria framework is proposed. This model incorporates quantitative, qualitative, and mixed criteria to monitor the diverse aspects of vocal function in the context of voice intervention. Conclusion: The model provides a precise guide to assess the results achieved by the patient in vocal intervention through treatment goals.
Introducción: La complejidad del fenómeno vocal dificulta que el/la terapeuta monitoree de manera rápida y eficaz los logros obtenidos por el/la usuario/a mediante la intervención fonoaudiológica. La evaluación del avance terapéutico depende de la habilidad del/la terapeuta para emplear criterios de medición válidos, confiables y significativos. Objetivo: Desarrollar un modelo teórico de criterios de logro para su consideración en la formulación de los objetivos operacionales en las planificaciones terapéuticas que emplean los profesionales fonoaudiólogos en la atención de usuarios/as que presentan queja vocal. Metodología: Investigación cualitativa, de tipo conceptual y modélica, en la que se lleva a cabo una revisión crítica de la literatura a través de un muestreo teórico no probabilístico de los modelos teóricos propuestos para la formulación y medición de objetivos en el contexto terapéutico y sus alcances respecto de la intervención vocal. A partir de ello, se propone una taxonomía de criterios de logro para la verificación del avance terapéutico. Resultados: Se propone una taxonomía organizada en torno a criterios de logro cuantitativos, cualitativos y mixtos, los que son propuestos para el monitoreo de diversos aspectos de la función vocal en el contexto de la intervención fonoaudiológica. Conclusión: El modelo proporciona una guía precisa para evaluar de manera efectiva el progreso y los resultados alcanzados por el/la usuario/a en el abordaje fonoaudiológico vocal a través de los objetivos operacionales planteados para la intervención.
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ABSTRACT Introduction: Superposing 3D models is an imminent need. However, current methods rely on marking multiple points on the maxilla and mandible, which could increase point marking and overlapping errors. Objective: This study aimed at developing a method for superimposing 3D models of the maxillary and mandibular arches with Autodesk Inventor® engineering software, using a single universal coordinate system (UCS) point superposition. Methods: A total of 104 STL (stereolithography) models of the maxillary and mandibular arches exported from My iTero® platform were retrospectively selected, in which T0 and T1 were the initial and refinement periods, respectively (n=26 per group). The X, Y, and Z coordinates associated with a single point in each arch were inserted into the models with SlicerCMF® software for model orientation. The arch models with UCS registration were transferred to Autodesk Inventor® for superimposition and to measure tooth movements performed during Invisalign® treatment. Arch expansion, intrusion and rotation were analyzed by two examiners. The statistics were performed using intraclass correlation coefficients (ICC), Dahlberg's formula, and t-test (p<0.05). Results: A reliable method of superimposing 3D digital models using a single UCS point in the maxilla and mandible was developed. ICC showed excellent intra- and inter-examiner correlation (ICC>0.90). A systematic error was not found concerning linear and angular measurements (<1mm and <1.5°, respectively). Digital dental movements could be analyzed, including arch expansion, dental intrusion, and tooth rotation. Conclusions: The developed method was proven reliable and reproducible for superimposing 3D models of the maxillary and mandibular arches by using UCS system.
RESUMO Introdução: A sobreposição de modelos 3D é uma necessidade iminente. No entanto, os métodos atuais dependem da marcação de múltiplos pontos na maxila e na mandíbula, o que pode aumentar a incorporação de erros no processo de sobreposição. Objetivo: O objetivo desse estudo foi desenvolver um método para sobrepor modelos 3D das arcadas superior e inferior utilizando o software de engenharia Autodesk Inventor®, por meio da marcação de um único ponto em cada arcada, usando o sistema de coordenadas universal (UCS). Métodos: No total, 104 modelos STL das arcadas superior e inferior exportados da plataforma My iTero® foram selecionados retrospectivamente, onde T0 foi o período inicial e T1, o de refinamento (n=26 por grupo). As coordenadas X, Y e Z associadas a um único ponto em cada arcada foram inseridas nos modelos usando o software SlicerCMF®. Os modelos com os pontos UCS demarcados foram transferidos para o software Autodesk Inventor® para realizar a sobreposição e medir os movimentos dentários realizados durante o tratamento com Invisalign®. Os movimentos de expansão, intrusão e rotação foram analisados por dois examinadores. A análise estatística foi realizada usando os coeficientes de correlação intra-classe (ICC), fórmula de Dahlberg e teste t (p<0,05). Resultados: Foi desenvolvido um método confiável de sobreposição de modelos digitais 3D usando um único ponto UCS na maxila e mandíbula. O ICC apresentou excelente correlação intra e inter-avaliadores (ICC>0,90). Não foi encontrado erro sistemático nas medidas lineares e angulares (<1mm e <1,5°, respectivamente). Os movimentos dentários puderam ser analisados por meio do método proposto, incluindo expansão da arcada, intrusão e rotação dentária. Conclusão: O método desenvolvido provou ser confiável e reprodutível para sobreposição de modelos 3D das arcadas superior e inferior usando o sistema UCS com marcação de ponto único.
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Objective:To validate the feasibility of the gamma analysis method in the study of prescription dose conversion between logistic nanodosimetry model (LNDM) and microdosimetric kinetic model (MKM) basing on the Chinese self-developed model LNDM by applying clinical experiences of National Institute of Radiological Science (NIRS).Methods:Physical dose distributions derived from the MKM- and LNDM-based carbon ion treatment plans were compared via the method of gamma analysis under the open-source treatment planning platform matRad. In this way, the prescribed dose conversion factor between the MKM- and LNDM-based treatment plans was obtained. Using water phantoms, the influence of geometric shape, size, depth of target volume (TV), prescribed dose and field setting on the conversion factor was investigated comprehensively. Moreover, preliminary verification of the acquired conversion factor was conducted on the C-shape model and a case of liver cancer patient.Results:The conversion factor depended on the field setting rather than the TV shape. Under the condition of single field, the conversion factor was positively correlated with the size and depth of TV, and the prescribed dose. Moreover, the conversion factor was successfully verified using the C-shape model and the patient with liver cancer, where the gamma passing rates (2%/2 mm) of the physical dose distribution generated by the MKM and LNDM treatment plans were 92.79% and 91.19%, respectively.Conclusions:The conversion factors (f=D LNDM/D MKM) obtained in this study might provide guidance for the prescribed dose setting during the carbon ion treatment planning based on the LNDM. Besides, the gamma analysis method could be used for the study of the prescribed dose conversion between different models.
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Objective:In Shanghai Advanced Proton Therapy Facility (SAPT) of Ruijin Hospital Proton Therapy Center, the calculation accuracy of the commercial proton treatment planning system RayStation (V10), especially the accuracy of the proton range calculation, was measured and verified, aiming to provide reference for the clinical application of the treatment planning system.Methods:A head phantom was used to verify the calculation accuracy of RayStation. The phantom CT was imported into treatment planning system (TPS). The phantom was followed closely by a water tank with a one-liter cubic target. A single field verification plan with the prescribed dose of 200 cGy (relative biological effectiveness) was designed and implemented. Then, the measured distribution results were compared with the calculation results.Results:When the verification plan of the phantom was designed with the default settings of RayStation, the measured longitudinal dose distribution was approximately 4 mm deeper than that of TPS, indicating that RayStation overestimated the water equivalent thickness (WET) of the tissue substitute materials in the phantom. To study the range error, the actual beam was used to measure the WET of the soft tissue substitute material. The default setting of RayStation was fine-tuned according to the measured results. It was found that the error between the measured SOBP and TPS calculations was reduced to only 2 mm.Conclusions:Using the default setting of RayStation to calculate the stopping power of the phantom may cause a large range error. A method that combines tissue segmentation with the measured WET of the tissue substitute material is proposed to improve the range calculation accuracy of the TPS. The results show that the proposed method can improve the dose and range accuracy of the commercial TPS including RayStation for tissue substitute materials.
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Objective:To introduce the method and result of the modeling and preliminary dose verification of the treatment planning system used in the first domestic proton therapy device of China (Raystation 10B, a system of scientific research version with no available registration certificate) and to verify the modeling accuracy using dose verification result.Methods:The modeling method for a treatment planning system (TPS) mainly included the data acquisition and modeling of integrated depth dose (IDD) curves, the data acquisition and modeling of beam spot profiles in air, and the calibration and modeling of absolute dose by scanning a 10 cm ×10 cm square field with a spot spacing of 2.5 mm. By measuring the dose distributions in three cases with different complexity levels and comparing them with the dose distributions calculated using the TPS, this study verified and analyzed the modeling accuracy and proposed the requirements for beam parameters and the commissioning suggestions of the proton device.Results:The peak values of the IDD curves of low-energy regions fitted using the TPS model were less than the measured values, while those of medium- and high-energy regions fitted using the TPS model approximated the measured values. The range in all energy regions fitted accurately. For the three cases with different complexity levels, the deviation between the average dose calculated by the TPS and that measured was within ±5% (national standard for type tests of medical devices). Moreover, the DTA of high-dose-gradient areas was less than 3 mm.Conclusions:The modeling accuracy of the TPS generally meets the verification requirements. However, due to the low resolution of IDDs obtained by Monte Carlo simulation in the TPS model and the sharp Bragg peaks of low-energy regions, the IDD modeling accuracy of low-energy regions is insufficient.
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Objective:To propose an automatic planning approach for Eclipse15.6 planning system based on Eclipse scripting application programming interface (ESAPI) and evaluate its clinical application.Methods:20 patients with nasopharyngeal carcinoma and 20 cases of rectal cancer were selected in the clinical planning. The developed automatic planning script SmartPlan and RapidPlan were used for automatic planning and dosimetric parameters were compared with manual planning. The differences were compared between two groups by using Wilcoxon signed rank test. Results:The dosimetric results of automatic and manual plans could meet clinical requirements. There was no significant difference in target coverage in nasopharyngeal carcinoma planning between two groups ( P>0.05), and automatic plans were superior to manual plans in organs at risk sparing ( P<0.05). Except for the homogeneity index of PTV and the maximum dose of bowel in rectal cancer plans, the other dosimetric parameters of the automatic plans were better than those of the manual plans (all P<0.05). Conclusions:Compared with the manual plans, the automatic plans have the same or similar target coverage, similar or better protection of organs at risk, and more convenient implementation. The developed SmartPlan based on ESAPI has clinical feasibility and effectiveness.
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Brachytherapy plays an important role in radical radiotherapy of cervical cancer. At present, most hospitals in China use high-dose-ate brachytherapy, which irradiatevolume by simulating line source with a single approximate point source. Therefore, the dwell positions and dwell times can be optimized appropriately. However, due to various reasons, the initial state of the optimization plan must start from the standard loading pattern, and ensure that the optimized plan basically maintains the pear-shaped dose distribution. This paper introduces the standard loading pattern of intracavitary brachytherapy and intracavitary combined interstitial brachytherapy for cervical cancer through literature review, and expounds the planning optimization model and the constraints in the optimization process, to provide important reference for the planning of brachytherapy for cervical cancer.
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Objective:To build a systemic and automatic importing scheme for importing CT images and structures into the treatment planning systems (TPSs) of Eclipse and Monaco.Methods:Based on two TPSs of Eclipse and Monaco, the files of CT images and structures were automatically transported from OAR auto-delineation system to the importing directory of these two TPSs using batch script in Windows system. Following the standard importing procedures of these two TPSs, the automatically importing script of CT images and structures were developed using the application of UiBot. Finally, the CT images and structures were imported into these two TPSs opportunely.Results:By comparing the importing time using script and manual methods, the script not only achieved auto-importing CT images and structures into TPSs, but also yielded almost the same efficiency to manual method. The number of imaging layers in most patients was between 130 and 180, and the average manual and automatic importing time within this interval was 76 s and 75 s.Conclusions:Automatic scripts can be developed by using the automation function of UiBot combined with the actual problems of radiotherapy and repeated workflow. The efficiency of radiotherapy work can be significantly improved. Manual and time costs can be saved. It provides a novel alternative for the automation of radiotherapy procedures.
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@#This is a retrospective study, the organ doses of the bladder and the rectum were compared between routine PLATO V14.2.3 (Nucletron B.V., Veenendaal, The Netherlands) and newer version software Oncentra MasterPlan (OMP) V4.3 (Nucletron B.V., Veenendaal, The Netherlands) treatment planning systems (TPS). The treatment data of 32 intracavitary brachytherapy patients at Hospital Universiti Sains Malaysia from January 2010 to June 2015 were used. These data sets were used for catheter reconstruction for both PLATO and OMP TPS followed by independent verification using Excel. There was no significant difference in mean doses to organs at risk (OARs) that calculated by both TPS (p>0.05). The mean percentage of doses calculated by PLATO TPS for bladder and rectum were 66.58 ± 27.42% and 46.27 ± 14.47%, respectively. While, the mean percentage of doses for bladder and rectum calculated by OMP TPS were 65.68 ± 24.24% and 46.46 ± 16.66%, respectively. The mean percentage difference in doses comparison between independent verification calculation and PLATO TPS was 1.96 ± 6.00% and then became 6.37 ± 5.17% when it was compared with OMP TPS. Overall, the dose calculation differences for both versions of TPS were within the range recommended by Nuclear Regulatory Commission (NRC). The dose calculations of the two treatment planning systems showed good agreement and both could be used in planning intracavitary brachytherapy for cervical cancer. Whereas, Excel based independent verification is suitable to be implemented as routine dose verification programme prior to treatment delivery.
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Aim of Study: The goal of this research was to investigate if application of optimized imaging parameters, recommended in literature, would be effective in producing the image quality required for treatment planning of spinal radiation fields with metallic implants. Materials and Methods: CT images from an anthropomorphic torso phantom with and without spinal implants were acquired using different imaging protocols: raising kVp and mAs, reducing the pitch and applying an extended CT scale (ECTS) technique. Profiles of CT number (CT#) were produced using DICOM data of each image. The effect of artifact on dose calculation accuracy was investigated using the image data in the absence of implant as a reference and the recommended electron density tolerance levels (Δρe). Results: Raising the kVp was the only method that produced improvement to some degree in CT# in artifact regions. Application of ECTS improved CT# values only for metal. Conclusions: Although raising the kVp was effective in reducing metallic artifact, the significance of this effect on Δρe values in corrected images depends on the required tolerance for treatment planning dose calculation accuracy. ECTS method was only successful in correcting the CT number range in the metal. Although, application of ECTS method did not have any effect on artifact regions, its use is necessary in order to improve delineation of metal and accuracy of attenuation calculations in metal, provided that the treatment planning system can use an extended CT# calibration curve. Also, for Monte Carlo calculations using patient's images, ECTS-post-processed-CT images improve dose calculation accuracy for impure metals
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Objectives: The aim of this study is to address the limitation of combined intracavitary-interstitial (IC/IS) brachytherapy (BT) in locally advanced cervical cancer using standardized applicators and to determine the optimal dose distribution in patients with challenging tumors, innovative methods of customizing and optimizing the IS needle configuration for combined IC/IS BT are proposed and investigated. Materials and Methods: A software module that could customize the IS needle configuration and subsequently generate the digital model of guiding template for three-dimensional printing was developed and integrated into our in-house treatment planning system for BT. The inverse optimization method based on the technique of mixed-integer linear programming was introduced to determine the needle tracks out of a candidate pool and dwell times at corresponding locations to best meet dose objectives. A treatment planning study was conducted to evaluate the feasibility and performance of the proposed methods. Results: The workflow for combined IC/IS BT with customized and inverse optimized IS needle configuration was presented. Dosimetric results of the treatment planning study showed that sufficient target coverage could be obtained with the customized IS needle configuration for challenging cases. The proposed dose-based optimization method for IS needle configuration was feasible and effective. Improved target coverage and organ-at-risk sparing were achieved using the inverse planning method. Conclusions: Using the proposed methods of customizing and optimizing the IS needle configuration, the limitation in the standardized design of combined IC/IS applicators can be addressed, and sufficient target coverage is obtained in cervical cancer patients with unfavorable tumor topography and/or extra lateral expansion.
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Objective: The objective of this study is to assess the clinical effect and safety of ultrasound-guided percutaneous microwave ablation (US-PMWA) assisted by three-dimensional (3D) visualization operative treatment planning system in larger adrenal metastasis (LAM) (D ≥ 4 cm). Materials and Methods: From Dec 2011 to Dec 2017, 12 consecutive LAM patients with pathologically proven with a mean diameter of 5.2±1.3cm (range 4.1-7.6) were treated. Artificial ascites and thermal monitoring system as ancillary technique were used. The patients were followed up with imagings and complications were recorded. Results: The median follow-up period was 31 months (ranged 6–52 m). All LAM achieved completely ablation according to the 3D planning preoperation. Complete ablation was achieved in 10 (10/12, 83.3%) patients by one session and 2 patients (2/12, 16.7%) by two sessions. Recurrence was detected at the treated site in 3 patients (3/12, 25.0%) at 5, 9, and 13 months after ablation and received another ablation. Progression of metastasis disease at extra-adrenal sites occurred in 9 patients (9/12, 75%). Seven (7/12, 58.3%) patients died during the follow-up period. Therefore, the 1-, 2-, and 3-year local tumor control rates were 83.3%, 75.0%, and 75.0%, and 1-, 2-, 3- and 4-year overall survival rates were 91.7%, 75.0%, 50.0%, and 41.7%, respectively. No severe complications related to ablation occurred, except 3 (3/12, 25%) patients developed hypertension during ablation. Conclusions: US-PMWA assisted by 3D visualization preoperative treatment planning system maybe a safe and efficient therapy for LAM, which could promote ablation precision, improve the clinical outcomes
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Radiation therapy (RT) is widely used to treat cancer. Technological advances in RT have occurred in the past 30 years. These advances, such as three-dimensional image guidance, intensity modulation, and robotics, created challenges and opportunities for the next breakthrough, in which artificial intelligence (AI) will possibly play important roles. AI will replace certain repetitive and labor-intensive tasks and improve the accuracy and consistency of others, particularly those with increased complexity because of technological advances. The improvement in efficiency and consistency is important to manage the increasing cancer patient burden to the society. Furthermore, AI may provide new functionalities that facilitate satisfactory RT. The functionalities include superior images for real-time intervention and adaptive and personalized RT. AI may effectively synthesize and analyze big data for such purposes. This review describes the RT workflow and identifies areas, including imaging, treatment planning, quality assurance, and outcome prediction, that benefit from AI. This review primarily focuses on deep-learning techniques, although conventional machine-learning techniques are also mentioned.
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Objective@#To report an implementation method and results of an independent brachytherapy dose verification software (DVS).@*Methods@#The DVS was developed based on Visual C+ + and the modular structure design was adopted. The DICOM RT files exported from the treatment planning system (TPS) were automatically loaded into the DVS. The TG-43 formalism was employed for dose calculation. Six cervical cancer patients who underwent brachytherapy were retrospectively selected to test the DVS. Different applicators were utilized for each patient. Dosimetric parameters and γ analysis (0.1cm, 5%) were used to evaluate the dose difference between the DVS and the TPS.@*Results@#Compared with the TPS dose, the γ pass rates of the doses calculated by the DVS were higher than 98%. For CTV, the dosimetric differences were less than 0.29% and 0.53% for D100% and D90%. For bladder, rectum and sigmoid, the agreement of D0.1cm3, D1cm3 and D2cm3 within a 0.5% level.@*Conclusion@#With minimal human-computer interactions, the DVS can verify the accuracy of dose calculated by TPS for brachytherapy.
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Objective To report an implementation method and results of an independent brachytherapy dose verification software (DVS).Methods The DVS was developed based on Visual C++ and the modular structure design was adopted.The DICOM RT files exported from the treatment planning system (TPS) were automatically loaded into the DVS.The TG-43 formalism was employed for dose calculation.Six cervical cancer patients who underwent brachytherapy were retrospectively selected to test the DVS.Different applicators were utilized for each patient.Dosimetric parameters and γ analysis (0.1 cm,5％) were used to evaluate the dose difference between the DVS and the TPS.Results Compared with the TPS dose,the γ pass rates of the doses calculated by the DVS were higher than 98％.For CTV,the dosimetric differences were less than 0.29％ and 0.53％ for D100％ and D90％.For bladder,rectum and sigmoid,the agreement of D0.1cm3,D1cm3 and D2cm3 within a 0.5％ level.Conclusion With minimal human-computer interactions,the DVS can verify the accuracy of dose calculated by TPS for brachytherapy.
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BACKGROUND: The development of digital technology has changed the diagnosis and treatment process in traditional oral clinic. The digital workflow can improve patient’s comfort, and save time. Virtual articulator as the new development section has been used in most of the dental design software, which is to replicate the function of mechanical articulator and simulate static and dynamic occlusion. It makes treatment more convenient, accuract and efficient. OBJECTIVE: To review the recent progress in the field of operation and clinical application of multiple virtual articulators at home and abroad. METHODS: The first author searched the related literature, clinical cases and books by computer in domestic and foreign databases, and the related contents and opinions were summarized. RESULTS AND CONCLUSION: (1) Although it has been studied for about 20 years, virtual articulator has not been widely applied because of technical sensitivity and high cost. (2) The transfer of articulator needs to scan the mandible model and record the mandibular movement relation. To define mandibular movement relation, average mandible parameters can be used, the ultrasonic sensor, photoelectric sensor, digital face bow or cone beam computed tomography for individualized records can also be used. (3) At present, virtual articulator has been used in fields of orthognathic surgery, temporomandibular joint disease, implant, and aesthetic repair. Comparative studies have shown that accuracy can meet clinical requirements and save time. However, differences between occlusal systems need to be detected. (4) Virtual articulator can save clinical operation time, improve accuracy, make up for the limitations of mechanical articulator, and has a wide range of application prospects.
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Aim: The aim was to measure doses of eyes and lenses in the presence and absence of shield during whole brain irradiation (WBI). In addition, the dose calculations accuracy of radiation therapy dose plan treatment planning system (TPS) in dose calculation of the eyes and lenses in WBI was evaluated. Materials and Methods: To measure the eyes and lenses doses during WBI, an inhomogeneous phantom of human head was used. Then, the eyes and lenses doses in the presence and absence of shield were measured by EBT3 film. Results: In single fraction with 200 cGy to reference point, average doses received by the left and right eyes in the absence of shield were 20 ± 1.5 and 22 ± 1.0 cGy, respectively, and for the left and right eyes in the presence of shield were 18 ± 2.2 and 21 ± 2 cGy, respectively. In addition, the average dose received by the left and right lenses in the absence of shield were 19.5 ± 0.5 and 18.5 ± 0.5 cGy, respectively, and for the left and right lenses in the presence of shield were 20.5 ± 1.5 and 19.5 ± 1.5 cGy, respectively. The results showed the TPS compared to the film underestimates doses for the eyes and lenses. Conclusion: The average dose received by the eyes and lenses during WBI were estimated around 9–11% of prescribed dose. According to the results, there is probability of radiation-induced cataractogenesis during WBI. By investigating the effect of shield on the lenses and eyes doses, using shield during WBI is not recommended. In addition, the results showed dose calculation accuracy of the TPS for the estimation of doses received by the eyes and lenses during WBI is not acceptable
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Objective To investigate the commissioning and testing of the Eclipse model of an Edge accelerator with high-definition muhi-leaf collimator (HD-MLC).Methods The percentage depth dose (PDD),profile,output factor measured by Razor and CC13 were statistically compared with the standard data.Penumbra,transmission factor (TF),leakage,concave-convex groove,accuracy of movement and dosimetry leaf gap (DLG) were measured with EBT3,electronic portal image device (EPID) and PTW SRS1000&SRS1500.The optimal DLG/TF was acquired when the γ pass rate of test cases was the highest.The point dose of regular fields,intensity-modulated radiation therapy (IMRT) and volume-modulated radiation therapy (VMAT) was verified with FC65-G.The planar dose of these case was verified with Octavius 4D and EBT3.Results The measured PDD data were consistent with the standard data.The measured penumbra of 3 cm and 4 cm square fields was smaller,whereas that of 6 cm square field was larger than the standard values.The left and right edge,field size,center of the field were distributed within the range of-1.0-0.4 mm、0.2-1.7 mm,-0.3-1.9 mm and-0.1-0.8 mm,respectively.The mean penumbra of the left and right MLC in different positions were (2.5±0.042) mm and (2.7±0.005) mm.The leakage of MLC was 0.009-0.016.The measured DLG/TF was 0.1861 cm/0.0116 and the optimal DLG/TF was 0.015 cm/0.014.The differences of point dose of all the test cases except the one which was in the low-dose area were within ±3％.Local and global γ pass rates of all IMRT were 79.81％-100％ and 96.3％-100％ (3％/3 mm),71.3％-98.9％ and 94.3％-99.8％ for VMAT cases.Conclusions This method can accurately test and commission the Eclipse treatment planning model of Edge Linac equipped with HD-MLC.
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Objective@#To investigate the effect of simple artifacts on the calculation of radiation dose in actual clinical operations by the aid of artificially caused CT artifacts.@*Methods@#The phantom was scanned using CT before and after replacing the titanium alloy component. Then, the CT values were measured at different distances before and after replacement. After correcting the CT value of the titanium alloy region to the CT value of the water phantom, the doses to the phantom were calculated by using Varian′s AAA algorithm, AXB algorithm and Pinnacle system′s CCC algorithm. The absolute dose values at different distances were furtherly analyzed.@*Results@#Varian system was consistent with Pinnacle system in evaluating the CT values. When the CT value deviated by less than 30 HU for a uniform phantom, the dose deviations of the three different algorithms were within 6.0 %-12.0 % at a distance of 0.5 cm from the body surface, and less than 1.0% at a distance of more than 1.5 cm from the body surface. When the CT value deviated by 15 HU for the lung phantom, both Varian′s AAA algorithm and Varian′s AXB algorithm showed about 1.0% dose deviation. However, the CCC algorithm of the Pinnacle system had a significant difference (5.0%) in dose values under the same conditions.@*Conclusions@#CT artifacts have noticeable effects on the calculation of radiation dose and change tissue dose distribution which may result in insufficient or excessive exposure doses.
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Objective To evaluate the feasibility of utilizing dose-volume histogram (DVH) prediction models of organs at risk (OARs) to deliver automatic treatment planning of prostate cancer.Methods The training set included 30 cases randomly selected from a database of 42 cases of prostate cancer receiving treatment planning.The bladder and rectum were divided into sub-volumes (Ai) of 3 mm in layer thickness according to the spatial distance from the boundary of planning target volume (PTV).A skewed normal Gaussian function was adopted to fit the differential DVH of Ai,and a precise mathematical model was built after optimization.Using the embedded C++ subroutine of Pinnacle scripa,ahe volume of each Ai of the remaining validation set for 12 patients was obtained to predict the DVH parameters of these OARa,ahich were used as the objective functions to create personalized Pinnacle script.Finalla,automatic plans were generated using the script.The dosimetric differences among the original clinical plannina,aredicted value and the automatic treatment planning were statistically compared with paired t-test.Results DVH residual analysis demonstrated that predictive volume fraction of the bladder and rectum above 6 000 cGy were lower than those of the original clinical planning.The automatic treatment planning significantly reduced the V70,V60,V50 of the bladder and the V70 and V60 of the rectum than the original clinical planning (all P＜0.05),the coverage and conformal index (CI) of PTV remained unchangea,and the homogeneity index (HI) was slightly decreased with no statistical significance (P＞ 0.05).Conclusion The automatic treatment planning of the prostate cancer based on the DVH prediction models can reduce the irradiation dose of OARs and improve the treatment planning efficiency.