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Objective To explore the dosimetric effect of using a split of the gross tumor volume (GTV) delineation approach during intensity-modulated radiotherapy (IMRT) treatment planning for advanced T-stage nasopharyngeal carcinoma (NPC) with prevertebral space involvement (PSI).Methods Twenty NPC patients with T3-T4 tumors with prevertebral space involvement were studied.Two kinds of plans were generated based on the same protocol.The first plan was GTV-split consisting of organ at risk (including spine cord and brain stem) overlapping and non-overlapping subsegments.The subsegments were assigned independent dose constraint.The second plan was done based on a standard treatment planning protocol.The two plans were compared with respect to target coverage and organ at risk (OAR) sparing,and target conformity index.Results Two plans both met requirement of dose coverage of target and constraints on normal tissue.Regarding the planning gross target volume (PGTV),the doses of ＜ 93％ volume of plan 1 and plan 2 were [(0.63 ± 0.21)％,and (0.68 ± 0.10)％,P =0.049];the doses of ＞ 110％ volume of plan 1 and plan 2 were [(11.59 ± 7.Ol) ％,and (12.71 ± 6.03) ％,P =0.041];the doses of ＞115％ volume of plan 1 and plan 2 were [(2.05 ± 0.80)％,and (2.76 ± 1.14)％,P =0.049];about OARs,the maximal dose of spine cord for plan 1 and plan 2 were (41.00 ± 4.52) Gy and (45.00 ± 3.25) Gy (P =0.048);and the target coverage and target conformity index of plan 1 were better than those of plan 2,the p-values were 0.063,and 0.135,respectively.The difference between two plans was statistically significant (P ＜ 0.05).Conclusions A split-GTV delineation,independent dose constraint,and multi-course IMRT for advanced T-stage nasopharyngeal carcinoma with prevertebral space involvement optimized IMRT treatment planning,improved target coverage and target conformity index,and decreased the maximal dose for the spine cord and brain stem.It is feasible and has advantage to decrease the dose to OARs.The approach deserves to be further studied.
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Objective To develop information system for radiotherapy. Methods The radiotherapy information the system adopts B/S structure mode,ACCESS 2010 as the database Server at the front desk, running on the hospital local network,background database is called Oncentra TPS and SQL Server 2008 in Mosaiq system, using ASP programming language network, the system is in Macromedia Dreamweaver 8 platform development. Based on the Internet information services ( IIS) 6. 0 6. 0 build system server service components,IE browser is used to implement the client access server capabilities. Results The information system including system Settings module,physics teacher module,the doctor module,technician module,data statistics and analysis, data download, seven modules such as video teaching. Conclusions The Radiotherapy information system is real?time performance, data security, stable operation, is the key construction for efficient utilization of resources in radiotherapy.
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Objective To evaluate the clinical value of the afterloading brachytherapy inverse intensity-modulated radiotherapy of gynecological tumor.Methods Twenty patients with cervical cancer,were randomly divided into A and B groups,10 cases for each group.Group A received the afterloading brachytherapy inverse intensity-modulated radiotherapy.Group B received the three-dimensional comformal afterloading brachytherapy.The target volume dose distribution,organs at risk (rectum,bladder),shortterm curative effect and radioactive complications were analyzed on both groups.Results The dose homogeneity index of the target volume of group A was 52.43-± 0.45,better than that of group B (46.37 ± 1.45) (t =0.92,P ＜ 0.05).The maximum dose of rectum and bladder of group A were about 37％,35％,less than that of group B (t =1.34,1.39,P ＜ 0.05).The 75％ prescription dose irradiated volume of rectum and bladder of group A were about only 1/2 of group B (t =1.23,1.13,P ＜ 0.05).The local control rate of 96％ for group A was better than 93％ for group B (t =1.25,P ＜ 0.05).Conclusions Afterloading brachytherapy inverse intensity-modulated radiotherapy technique could be better than the three-dimensional comformal afterloading brachytherapy.It should be recommended for gynecological tumor.
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Objective To study the laws of heating and thermal field of heating seed arrays in different magnetic field intensity during the magnetic induction hyperthermia.Methods 3.0 cm×3.0 cm ×2.6 cm and 5.0 cm ×5.0 cm×2.6 cm of magnetic heating seed was implanted respectively in 10.0 cm×10.0 cm ×10.0 cm pure agar phantom.The regions was divided into one file per 5 Gs in the range of 60-120 Gs magnetic induction.The temperature measurement experiments were implemented in each sub-file.Muscle-agar mixture model was used in the magnetic induction 60 Gs and 90 Gs to implement GTV-heating simulation experiments and thermal field analysis.Results The pure agar phantom heating experiments show that the heating is of basically the same rule when seeds with various diameters were implanted in the magnetic thermal array.Along with the increase of magnetic induction,the final temperature of the focal point heated for 40 min increased accordingly.and time required for heating to 50℃ was shortened correspondingly.The thermal field analysis of muscle-a mixture agar mixture model showed that the implantation density of magnetic heating seed is closely associated with the temperature of the target area and thermal field in difierent magnetic field intcnsity.Conclusions The magnetic induction has a significant impact on heating of the seeds,as the magnetic modium,and this impact is trending downwards when the magnetic field reaches a certain intensity.Within a certain size,adequate magnetic heating seed density is necessary to achieve the desired temperature required for the temperature value.The heating seeds should be put in a certain order to heat the venue evenly,not in a simply order,but in line with the principle of outer dense and inner sparse.
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This article describes the physical, technical, and dosimetric aspects of total body irradiation (TBI) that was carried out by using 6MV X-Ray from Varian 2300 C/D Linear Accelerator at a distance of 450 cm from target to the treatment table and at a gantry angle of 270°.The dose to lung tissue was limit by setting the individual lead compensators customized before, and using DPD-510 to monitor the absorbed dose of the reference point the absorbed dose in depth of half of body will be (Din+Dout)/2 after taking treatment in both AP position and PA position.