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@#<b>Objective</b> To compare the set up errors derived from different registration methods of the X-ray volume imaging (XVI) system for radiotherapy in the treatment of middle/lower-segment esophageal cancer, and to provide a reference for radiation treatment of esophageal cancer. <b>Methods</b> We randomly selected 63 patients with middle/lower-segment esophageal cancer, and obtained their reconstructed XVI images at the first therapy to perform automatic registration with gray-value and bone registration methods. We acquired and compared the three translation errors (along <i>x</i> [left to right], <i>y</i> [head to feet], and <i>z</i> [front to back] axes) and three rotation errors (around the <i>x</i>, <i>y</i>, and <i>z</i> axes) derived from the two registration methods. <b>Results</b> Gray-value registration had significantly smaller translation errors along the <i>x</i> and <i>z</i> axes than bone registration (<i>x</i> azes <i>t</i> = −2.78, <i>z</i> azes <i>t</i> = −2.15, <i>P</i> < 0.05), but there was no significant difference along the <i>y</i> axes (<i>P</i> > 0.05). The rotation errors around the three axes were all smaller than 1°, and were smaller with gray-value registration than with bone registration, but without significant differences (<i>P</i> > 0.05). <b>Conclusion</b> We recommend gray-value registration for radiotherapy in the treatment of middle/lower-segment esophageal cancer. Manual verification or fine-tuning is recommended after automatic registration in clinical practice. Besides translation errors, rotation errors should also be paid attention to.
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Objective The literature study the setup errors of head and neck, thoracic, abdominal and pelvic tumors by megavoltage fan-beam CT based image guidance in TOMO-HD to provide the margin enlarging from clinic target volume (CTV) to planning target volume (PTV) in treatment planning system of TOMO-HD. Methods 103 patients with head and neck (30 patients), thoracic (42 patients), abdominal and pelvic (31 patients) carcinoma were enrolled. Megavoltage fan-beam CT based image guidance in tomotherapy-HD was used to acquire CT scan before every treatment. The left-right (X), superior-inferior (Y), anterior-posterior (Z) and rotation (Fy) setup errors of patients can be obtained from the tomography image automatically restructured by the system. Calculating the systematic error and the random error in the three dimensions and check whether the setup data accord with the normal distribution or not, then acquire the data expand in the three directions. Results According to 2593 fan-beam CT scans, the shift errors (µ ± s) in X, Y, Z and Fy (rotation) of three study group were [(−0.31 ± 2.16) mm、(1.09 ± 3.56) mm、(2.36 ± 2.27) mm, (0.29 ± 0.96)°] (head and neck tumor), [(−0.98 ± 2.95) mm、(0.45 ± 6.86) mm、(3.79 ± 2.47) mm, (0.18 ± 0.60)°] (thoracic cancer) and [(−0.86 ± 2.85) mm、(−1.59 ± 6.91) mm、(5.77 ± 2.40) mm, (0.20 ± 0.68)°](abdominal and pelvic carcinoma). The systematic errors (∑) and random errors (σ) in X, Y, Z dimensions of patients with head and neck, thoracic, abdominal and pelvic tumors were (1.06 mm and 1.84 mm), (1.93 mm and 3.43 mm), (2.41 mm and 2.71 mm), (1.10 mm and 2.56 mm), (3.79 mm and 5.46 mm), (1.38 mm and 1.99 mm) and (1.39 mm and 0.87 mm), (4.98 mm and 5.69 mm), (1.19 mm and 2.05 mm), respectively. Conclusion It is recommended as a reference for image guidance in TOMO-HD according to the frequency distribution of setup errors, for patients with head and neck, chest and abdominal and pelvic tumors, the maximum range of motion in three dimensions are (5.00, 5.00, 5.00) mm, (6.63, 17.25, 16.00) mm and (6.49, 16.24, 13.60) mm.
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Objective:To explore the application of ArcCheck system in the validation of Helical and Direct tomotherapy plans for esophageal cancer and summarize relevant experience.Methods:The Helical and Direct tomotherapy verification plans were established for 32 patients with esophageal cancer at different positions according to the doctor′s instructions, which were verified by the ArcCHECK system to compare the passing rate of the results.The correlation between the volume of the target area and the passing rate of the planned verification was analyzed. The therapeutic verification plan with a small target volume was made. The target area was placed at the center of ArcCHECK phantom and the area of detectors to statistically compare the verification passing rates.Results:Helical plan showed a significantly higher passing rate than the Direct plan ( P<0.01). The correlation coefficients between the target volume and the passing rate of the Helical and Direct plans were -0.364 and -0.042, and the P values were 0.041 and 0.819, respectively. For the Helical plan, when the 3%/2mm criterion was adopted, there was significant difference between placing the high-dose area at the center of the phantom and the area of detectors ( P=0.005), and the passing rate of the latter was higher. There was no significant difference in the other cases (all P>0.05). Conclusions:The passing rate of the Helical plan is generally higher than that of the Direct plan, which may be related to the angular response of the ArcCHECK detector and the fact that more reference points are not included for calculation due to low-dose radiation. In addition, it may also be related to the higher requirements of Direct plan for tomotherapy dose control system. In the Helical verification plan, when the 3%/3mm criterion is adopted, the larger the target volume, the higher the possibility of lower passing rate, whereas the correlation coefficient between them is relatively low. The high-dose area can be verified by the plans at the center of the phantom or the detection point. With the comprehensive consideration, we suggest putting it at the center of the phantom.
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Objective To compare the dosimetric difference among TomoDirect (TD) radiotherapy,Helical Tomotherapy(HT) and volumetric modulated arc therapy(VMAT) in the treatment of upper thoracic esophageal carcinoma.Methods A total of 15 patients with cT2-4 N0-1 M0 upper thoracic esophageal squamous cell carcinoma were enrolled.Three plans were generated using the same dose objective for each patient:TD,HT and VMAT.Dose-volume histogram (DVH),homogeneity index (HI),conformal index (CI),dose at organ at risk (OAR),delivery time and monitor unit (MU) were compared among different plans.Results The D2 and D values in the HT and TD plans were significantly lower than those in the VMAT plans.The D98 value in the TD was similar to that in the HT,but lower than that in the VMAT.The HI of HT was significantly better than those of TD and VMAT (F =81.603,P ＜ 0.05).For the CI,there was no significant difference among the three techniques (P ＞ 0.05).For the V15 of lung,HT was significantly higher than TD (t =-2.626,P ＜0.05) and VMAT (t=3.547,P ＜ 0.05).The V20 of lung in TD was similar to that in HT,but higher than that in VMAT (t =2.824,3.052,P ＜ 0.05).The Dmax of spinal cord showed no significant difference among the three techniques.VMAT had a significantly shorter delivery time and lower MU compared with HT and TD (t =21.617,15.693,10.018,7.802,P ＜ 0.05).Conclusions HT and TD could gain a better planning target volume (PTV) coverage and HI than VMAT in the treatment of upper thoracic esophageal carcinoma.However,VMAT achieved the lowest lung V20,the least Mus and the shortest delivery time.HT achieved a better PTV coverage compared with TD,but TD had a lower lung V15 Mus and shorter delivery time compared with HT.
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Objective To explore the value of DWI (diffusion weighted imaging,DWI) in diagnosis of bladder cancer in clinical T stage by comparing DWI and CT.Methods Seventy-five patients with bladder cancer underwent MRI plain scan,enhanced diffusion-weighted imaging and CT scan,to make a diagnosis preoperative clinical T stage according to their image.Then we compared the diffusion-weighted imaging and CT results with pathological staging results to assess the value of DWI in bladder tumor staging.Results For clinical T staging bladder cancer,the diagnostic accuracy rate was 83.5％ and 72％ for DWI and CT,resectively,statistical analysis showed a significant difference (P ＜0.05).Conclusion Magnetic resonance diffusion weighted imaging can accurately diagose the clinical T stage of bladder cancer,and has a higher value than CT.
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Objective To compare the dosimetry between three -dimensional conformal radiotherapy (3DCRT)and intensity -modulated radiotherapy(IMRT)in the treatment of upper thoracic esophageal carcino-ma,and to provide references to choose radiotherapy program for clinical physician .Methods twenty-five cases with upper esophageal carcinoma (clinical stageⅠ~Ⅲstage)were treated by 3DCRT and IMRT at the concentra three-dimensional radiation treatment planning system .The different exposure doses between target area and effected organs were compared by dose volume histogram ( DVH) with the planed target volume ( PTV) ,which must reach 95% of the prescriptive doses.Results Two different radiotherapy plans of IMRT and 3DCRT:V95, (99.91 ±0.14)%,(95.73 ±4.14)% respectively,P0.05;targeting minimum dose(Dmin)were(5 458.88 ±184.06) cGy,(4541.60 ±599.0)cGy,P0.05;Lung V10 (35.39 ±11.41)%,(29.0 ±8.80)%,P<0.05,Lung V5(44.95 ±15.55)%,(37.27 ±11.93)%,P<0.05. Conclusion Intensity-modulated radiotherapy is better than 3DCRT technology in showing PTV volume ,target conformal degrees and the mean index ,spinal cord protection ,However ,The risk of lung injury could be increased with the enlarged area of low -dose irradiation in lung .
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OBJECTIVE@#To explore the difference of the threshold of auditory steady-state evoked responses (ASSR) in awake and sleeping.@*METHOD@#Fifteen adults (30 ears) with normal hearing were selected to ASSR test. ASSR parameters: carrier frequency (CM)are 0.5, 1.0, 2.0, 3.0, 4.0, 6.0 kHz, modulation frequency (FM) are 46.81 Hz. The test was performed in two different status (in awake and sleeping).@*RESULT@#In awake, the thresholds of ASSR with FM of 46 Hz are significantly lower than 81 Hz (P < 0.01); In sleeping, the thresholds of ASSR with FM of 81 Hz are lower than 46 Hz above 2 kHz CM (P < 0.05), which thresholds were close to pure tone.@*CONCLUSION@#To select low modulate (46 Hz) frequency in awake, and use high modulate (81 Hz) frequency in sleeping. When perform ASSR test, the test values are closer to the actual hearing threshold.