Acupuncture Therapy ; Adolescent ; Drugs, Chinese Herbal ; administration & dosage ; Female ; Furunculosis ; drug therapy ; therapy ; Humans

Objective To compare the dosimetric differences between helical tomotherapy (HT) and volume-modulated arc therapy (VMAT) in the treatment of upper thoracic esophageal carcinoma (UTEC).Methods A total of 10 patients with UTEC were randomly selected.HT plan and double-arc VMAT plan were designed and optimized for each patient.The prescription dose was 50 Gy/30 fractions for gross target volume (GTV), 66 Gy/30 fractions for planned target volume (PTV).The dose distribution and conformal index (CI), homogeneity index (HI) of target volume, the D1％, D5％, Dg5％, D99％, and dose of organ at risk (OAR) were analyzed by using the dose volume histogram (DVH).The monitor units and delivery time were also evaluated.Results For GTV and PTV, the D99％ of HT plans were slightly higher than those of VMAT plans (t =4.476, 3.756, P ＜ 0.05) , but no significant differences in D1％ , D5％ , D95％ , HI and CI (P ＞ 0.05) were found.The V10, V15, V20 and mean lung dose (MLD) to the total-lung of HT plans were all significantly lower than those of VMAT plans (t =-3.369,-4.824, -4.869,-3.657, P ＜ 0.05).There were no significant differences for V5, V30 and Dmax of cord (P ＞ 0.05).The monitor units and delivery time of VMAT plans were significantly lower than those of HT plans (t =13.970, 7.982, P ＜ 0.05).Conclusions Both HT and VMAT are appropriate for esophageal cancer radiotherapy.HT significantly reduces the radiation dose of the total-lung, while VMAT has obvious advantages in efficiency.

OBJECTIVETo evaluate the feasibility and accuracy of using Megavoltage CT(MVCT) for head and neck dose calculation.

METHODSThe cheese Phantom was imaged using MVCT scanner, and the MVCT value density calibration curve was established. Conventional CT and MVCT image of nasopharyngeal carcinoma was acquired respectively, and IMRT plan was designed on conventional CT image of NPC patient. The conventional CT plan was copied to MVCT image. The dose distribution was calculated for tumor and normal tissue using the MVCT value density calibration curve, and compared with that of conventional CT. Ten NPC patients were collected for dose verification of IMRT plan on MVCT images.

RESULTSThe MVCT numbers depended linearly on the electron density of the sample, and the stability of the MVCT numbers to electron density was good.The error between the measured dose and calculated dose in measured point was less than 3%.The isodose distribution was well agreement with that calculated by planning system.

CONCLUSIONSPerforming dose recalculation using MVCT of Tomotherapy in head and neck region was feasible.and the dose distributions on kVCT and MVCT were in excellent agreement.

Algorithms ; Head and Neck Neoplasms ; radiotherapy ; Humans ; Phantoms, Imaging ; Radiosurgery ; instrumentation ; methods ; Radiotherapy Dosage ; Tomography, Spiral Computed ; instrumentation

Objective To research the structure and principle of Helical Tomotherapy, and study the clinical application value of the equipment system. Methods As the first helical radiotherapy system in the mainland of China, its constructions, structure and principle were analyzed and discussed. Results Helical Tomotherapy is a new kind of radiotherapy equipment. The Hi-Art treatment system is a combination of a LINAC and a CT scanner capable of having the function of both systems. It was approved to achieve the best intensity modulated radiation therapy (IMRT), used for adjusting the setup position of the patient with MVCT and as the basis for dose reconstruction and other adaptive radiotherapy processes. It is the first integrated planning, delivery and verification system for IMRT. Conclusion Image-guided radiation therapy (IGRT) and IMRT have introduced a new era in radiation oncology which will better fight cancer and simultaneously improve the patients' quality of life. Having been designed from the ground up for IGRT and IMRT, the tomotherapy system is in the forefront of technical advancements for efficacy and processes to make it efficiently.

Objective To evaluate the absorbed doses of lower-neck and supraclaviclar subclinical target and the normal tissues of nasopharyngeal carcinoma using three different intensity-modulated radiation therapy (IMRT) techniques. Methods Three radiotherapy techniques were single tangential low neck-supraclavicular field technique (tech1), seven portal IMRT in which the gantry angles are 180°, 150°, 120°, 90°, 270°, 210°(tech2) and 240°and eight portal IMRT in which the gantry angles are 180°, 150°, 120°,90°,0°,270°,210°and 240°(tech3). The dose distribution of lower-neck and supraclaviclar subclinical target and normal tissues were analyzed through the dose-volume histograms, high dose volumes were analyzed using V60 (volume of accepted > 60 Gy/all volume × 100%). The delivery efficiencies were evaluated by means of the total number of segments and MUs. Results The V60 of PTV2 were 65%, 10% and 3% in tech1, tech2 and teeh3 respectively. The maximum doses of spinal cord were 42.0, 48.9 and 45.1 Gy in techl, tech2 and tech3 respectively. The average doses of trachea were 32.92, 52.17 and 36.56 Gy in techl, tech2 and tech3 respectively. Conclusions Tech1 is simple method, but the dose distribution is very nonuniform. Tech2 is better than the Tech1, but the spinal cord and trachea receive the highest doses in three strategies. Tech3 uses less number of segments and MUs than Tech2, and has the best dose distribution.

Objective:To analyze the awareness rate of obesity risk factors among children and adoles-cents, and to provide the basis for preventing their obesity. Methods: The students selected by using stratified cluster sampling method, were measured for the body height, weight, and waist circumference, and were surveyed for the awareness rate of obesity risk factors by using the questionnaire. The distribu-tion characteristics of awareness on obesity risk factors were analyzed. Results: The awareness rate of obesity risk factors was 74 . 1%, and there was no significant difference on the awareness rate of obesity risk factors between the males [71. 2% (247/347)] and females [77. 2% (257/333)], the abdominal obesity students [73. 5% (202/275)] and non-abdominal obesity students [74. 6% (302/405)], the overall obesity students [74. 3% (185/249)] and non-overall obesity students [74. 0% (319/431)], re-spectively. However, the awareness rate of obesity risk factors among the primary school students was 81. 9% (272/332) that was higher than that of the middle school students [66. 7% (232/348)] (P<0. 05). Compared with the primary school students, the non-awareness risk of obesity risk factors would in-crease among the middle school students (OR=2. 23, P<0. 05). Conclusion:The overall awareness rate of obesity risk factors is not high among children and adolescents, especially among middle school students.

Objective To study dosimetric characteristics of helical tomotherapy (HT) by comparing its treatment plans with linear accelerator-based step-and-shoot intensity modulated radiation therapy (IMRT) for nasopharyngeal carcinoma(NPC). Methods Targets on CT images of 10 NPC patients were delineated and transferred to HT and IMRT treatment plan systems. The prescription dose was 70 Gy/33 f for pGTV and GTVnd,60 Gy/33 f for FTV1 ,and 54 Gy/33 f for PTV2. The limit dose of organ at risk was parotid V35 ＜50% ,brain-stem＜54 Gy,spinal cord ＜45 Gy and lens ＜9 Gy. Data of the two groups were compared by paired t-test. Results The dose distribution, conformality and homogeneity were good in both groups.But the homogeneity index(HI) and Dmean of PTV1 in HT group were better than IMRT group( P ＜ 0.01 ).The Dmean of PTV1 in HT group(63.84 Gy)was lower than IMRT group(70.30 Gy). The Dmean, V35 and V30 of parotids,and the Dmax of larynx-esophagus were lower in HT group than IMRT group. Conclusions Helical tomotherapy treatment plan has a better homogeneity, steeper dose gradient, and a better protection for organs at risk.

Objective To evaluate the dosimetric effect of carbon fiber tabletop on the patient doses in radiotherapy. Methods The transmission factors of couch and inserts were measured in air and solid water phantom using 0.6 cm3 ion chamber and PTW 2D ion chamber array for 6 MV ,10 MV and 18 MV X-ray,respectively. Absorbed doses at depth of maximum dose ,5 cm and 10 cm in solid water were measured with the 2D ion chamber array. Absorbed doses fluctuations with different gantry angles and air gaps between phantom and couch were also measured. Results The posterior field measurement showed that the reductions of absorbed doses at the depth maximum dose,5 cm and 10 cm were within 5%. The ratios of the absorbed doses with to without couch increased with the oblique incident angles and varied slightly with the air gap at depth of 5 cm. The transmission factors of inserts were less than those of couch owing to its thinner thickness. Conclusion The carbon-fiber tabletop affects the absorbed doses and dose distributions of the target, and this effect changes with the gantry angle and air gap. Special considerations should be taken during treatment planning.

Objective To develop a measurement method of dosimetric parameters for Hi-ART tomotherapy unit. Methods Percentage depth doses and beam profiles were measured using the dedicated mini water phantom, and compared to the results of 6 MV X-ray from Primus accelerator. Following the AAPM TG51 protocol, absolute dose calibration was carried out under SSD of 85 cm at depth of 1.5 cm for field of 5 cm ×40 cm. The output linearity and reproducibility were evaluated. The output variation with the gantry rotation was also investigated using 0.6 cm3 ion chamber in cylindrical perplex phantom and on-board MVCT detectors. Leaf fluence output factors were quantified for the leaf of interest and its adjacent leaves.Results The buildup depth was around 1.0 cm. The PDD values at 10 cm for Hi-ART and Primus were 59.7% and 64.7%, respectively. Varying with the field width, the lateral and longitudinal beam profiles were not so homogeneous as the Primus fields. The measured dose rate was 848.38 cGy/min. The fitted lint(sec) ,with a relative coefficient of 0. 999. The maximum deviation and standard deviation of output were 1.6% and less than 0.5% ; The maximum deviation and standard deviation of output changed by gantry angle were 1.1% and 0.5 % , respectively. Leaf fluence output factors did not increase significantly when leaves were opened beyond the two adjacent leaves. Conclusions Hi-ART Tomotherapy unit has a very high dose output and inhomogeneous beam profiles owing to its special design of the treatment head. This may be useful in dose calculation and treatment delivery.

Objective To examin and analyze the structure, ultrastructure and the circulation of the spleen ellipsoid in the soft-shelled turtle, Pelodiseus sinensis. Methods Twelve turtles were used and observed by light- and electron-microscopy and injection of ink suspension in this study. Results The spleen white pulp was consisted of the periarteriolar lymphatic sheath (PALS) and periellipsoidial lymphatic sheath (PELS). There was no lymphoid nodule in the spleen. Red pulp included splenic cords and splenic sinusoids. The marginal zone was not found in the turtle spleen. When the central arteriole left out of the PALS, it divided into several ellipsoid capillaries which were surround by the PELS. The end of the ellipsoid capillary opened directly to the splenic cord and the blood cells then entered into the splenic sinusoid through the gap between the endothelial cells. The ellipsoid capillary was consisted of simple cuboidal epithelium with an uncompleted basement membrane. The ellipsoid wall was consisted of supporting cells,ellipsoid-associated cells and reticular fibres. Lymphocytes and red cells were always found on the ellipsoid wall. After 40min of the injection of ink suspesion, much carbon particles of ink were restricted on the wall. Conclusion The ellipsoid capillary in the soft-shelled turtle, just like the high endothelial venule, was the important passage of the lymphocytes and blood cells going out and into the lymph tissue. The splenic circulation in the turtle belongs to the opening model.