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Objective:To explore the feasibility of the clinical implementation of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans with 6MV photon on two Elekta Linacs (Versa HD and Synergy) after beam matching.Methods:The images of 12 patients with nasopharyngeal carcinoma, central lung cancer and prostate cancer were randomly selected, and the IMRT and VMAT plans were designed. Two different dose tools of ionization chamber and three-dimensional detector ArcCheck were used to verify the individualized radiation treatment of 6MV photon beams on two Linacs and compare the differences.Results:The deviations between the doses of two Linacs (Versa HD and Synergy) measured by the ion chamber and treatment planning system were (0.32±1.32)% and (0.54±1.29)%. The differences of all plans were within the range of ±3%, and the deviations of the point dose between two Linacs were within the range of ±2% with no statistical significance (both P>0.05). The γ analysis of verification using ArcCheck showed that the passing rates of all plans under the 2mm/3% and 3mm/3% with 10% threshold conditions were over 95%, respectively. The average differences between two Linacs were 0.19%(2mm/3%) and 0.09%(3mm/3%). Conclusions:The results of performing IMRT/VMAT plans on two Linacs meet the clinical requirements and the differences between two Linacs are small. Hence, the same plans can be implemented interchangeably on different Linacs.
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Objective To study the dosimetric characteristics and plan quality of PTV-based intensity modulated proton radiotherapy (IMPT) and volumetric-modulated arc therapy (VMAT) plans for prostate cancer,so as to provide a reference for clinical application.Methods A total of 10 prostate cancer cases were included in this retrospective study.IMPT and RapidArc plans were designed by RayStation and Eclipse TPS based on PTV,respectively.For each case,IMPT plans were generated using multiple field optimization (MFO) technique with two parallel-opposed lateral fields,whereas RapidArc plans were generated using double-arc technique (two full arcs).Final dose calculation of IMPT was conducted by pencil beam (PB) and Monte Carlo (MC) algorithm,respectively,with adopted data model from the pencil beam scanning (PBS) proton therapy system of IBA Protues Plus (IBA Group,Belgium);The data model originated from the linear accelerator of Varian Clinac iX (Varian Medical Systems,America) was used for RapidArc plans.Dosimetric parameters of DVH and dose distribution were used to compare the dose differences in targets and organs at risk (OARs) between these two treatment techniques.Results For targets,HIs of PB-IMPT and MC-IMPT were slightly better than that of RapidArc,but CI of IMPT was slightly lower than that of RapidArc;D1 of PB-IMPT was significantly better than those of MC-IMPT and RapidArc (Z =-2.805,-2.803,P ＜ 0.05).PB-IMPT and MC-IMPT achieved better protection than RapidArc on rectum V30 (Z =-2.191,-1.988,P＜ 0.05) and D (Z =-2.599,-2.497,P＜0.05),bladder V30 (Z=-2.701,-2.701,P＜0.05),V40 (Z=-2.395,-2.395,P＜0.05) and D (Z =-2.701,-2.701,P ＜ 0.05).There was no significant difference between PB-IMPT and MC-IMPT plans for prostate cancer,except for the D1％ [(73.86t67.34) Gy vs.(75.45±2.01) Gy] (RBE) and HI [(0.040±0.010) vs.(0.058±0.020)] of the target.Conclusions Both techniques can meet the clinical requirements,but IMPT showed significant dosimetric advantages compared with RapidArch by reducing the dose to OARs and improving the plan quality.
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Objective@#To study the dosimetric characteristics and plan quality of PTV-based intensity modulated proton radiotherapy (IMPT) and volumetric-modulated arc therapy (VMAT) plans for prostate cancer, so as to provide a reference for clinical application.@*Methods@#A total of 10 prostate cancer cases were included in this retrospective study. IMPT and RapidArc plans were designed by RayStation and Eclipse TPS based on PTV, respectively. For each case, IMPT plans were generated using multiple field optimization (MFO) technique with two parallel-opposed lateral fields, whereas RapidArc plans were generated using double-arc technique (two full arcs). Final dose calculation of IMPT was conducted by pencil beam(PB) and Monte Carlo (MC) algorithm, respectively, with adopted data model from the pencil beam scanning (PBS) proton therapy system of IBA Protues Plus(IBA Group, Belgium); The data model originated from the linear accelerator of Varian Clinac iX (Varian Medical Systems, America) was used for RapidArc plans. Dosimetric parameters of DVH and dose distribution were used to compare the dose differences in targets and organs at risk (OARs) between these two treatment techniques.@*Results@#For targets, HIs of PB-IMPT and MC-IMPT were slightly better than that of RapidArc , but CI of IMPT was slightly lower than that of RapidArc; D1% of PB-IMPT was significantly better than those of MC-IMPT and RapidArc (Z=-2.805, -2.803, P<0.05). PB-IMPT and MC-IMPT achieved better protection than RapidArc on rectum V30(Z=-2.191, -1.988, P<0.05)and Dmean(Z=-2.599, -2.497, P<0.05), bladder V30(Z=-2.701, -2.701, P<0.05), V40(Z=-2.395, -2.395, P<0.05)and Dmean(Z=-2.701, -2.701, P<0.05). There was no significant difference between PB-IMPT and MC-IMPT plans for prostate cancer, except for the D1% [(73.86±67.34) Gy vs.(75.45±2.01) Gy] (RBE) and HI [(0.040±0.010) vs. (0.058±0.020)] of the target.@*Conclusions@#Both techniques can meet the clinical requirements, but IMPT showed significant dosimetric advantages compared with RapidArch by reducing the dose to OARs and improving the plan quality.
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Objective To realize the autom ated assessm ent of the levels of epiphysis of distal radius and ulna by support vector m achine (SVM). Methods The X-ray film s of the leftwrist jointswere taken from 140 teenagers aged from 11 to 19 years old as training sam ples. The levels of epiphysis of distal radius and ulnawere divided into five developm ental levels. Each level contained 28 sam ples. A nother 35 cas-eswere selected as independent verifying sam ples. SVM classification m odels of the five developm ental levels of epiphysis of distal radius and ulnawere established. The internal cross validationwas m ade by leave one out cross validation (LOOCV ),while the external validationwas m ade by histogram of orient-ed gradient (HOG), and then the accuracy (PA ) of testing resultswas calculated, respectively. Results The PA of SVM, LOOCV and HOG of distal radius epiphyseal levelwere 100%, 78.6%, and 82.8%, respec-tively;whereas the PA of SVM, LOOCV and HOGof distal ulna epiphyseal levelwere 100.0%, 80.0%and 88.6%, respectively. Conclusion The SVM -based autom atic m odels of the growth stage of distal ra-dius and ulna appear to have certain feasibility, and m ay provide a foundation for software developm ent of bone age assessm ent by forensic medicine.
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Objective To summarize the subtle anatomical structures of the normal nasal bone in mul-ti-slice spiral CT (MSCT) image through the observation of the three-dimensional images. Methods One hundred and twenty volunteers who had no nasal trauma and disease history were collected. The nasal was scanned using MSCT. Raw data was reconstructed into bone window images (slice thickness 0.6 mm, slice interval 0.5 mm), and then the images were imported into Syngo Imaging XS software to recon-struct three-dimensional images and to summarize the nasal bone ’s subtle anatomical structures. Results The subtle anatomy of normal nasal bone generally included four seams, two holes and one edge. The four seams were left and right nasal-maxillary suture, nasal-frontal seam, and internasal suture. The two holes were left and right nasal aperture. The edge of the nasal was the lower edge of the nasal bone. In addition, there was suture bone in internasal suture in some normal nose. The nasal aperture mostly was hole-like, but some nasal apertures were line shape. The nasal edge can be divided into flat type, wave-shaped type, inverted spike type, hook-shaped type and others. Conclusion The anatomy diversity and individual differences in nasal bone are large. MSCT and three-dimensional image reconstruction techniques, combined with the history of trauma could distinguish between the normal anatomy and fractures.