The image guided radio therapy (IGRT) Imaging System based on cone-beam computer tomography (CBCT) can reach the goal of improving the accuracy of the radiotherapy. However, because the clinical registration between CBCT images and Planning CT images is carried out manually, it inevitably reduces radiation positioning accuracy to some extent. To tackle the problem, we proposed a new feature vector selection method for the CBCT image elastic registration in the framework of hierarchical attribute matching mechanism for elastic registration (HAMMER) algorithm. We analyzed the characteristics of HAMMER algorithm and used Canny operator which has a better edge detection and positioning performance to replace the noise-sensitive gradient amplitude. Therefore, we used a new attribute vector, which consisted of the intensity, Laplacian of the Gaussian and Canny operator, to ex tract the image feature points in CBCT and planning CT images. We also presented an adaptive feature-point selection method and the choice criteria of attribute vector weights. Experimental results showed that the new feature vector effectively avoided the noise interference resulted from scattering lines in CBCT images to improve registration accuracy, and it also decreased the required feature point numbers and reduced the computation redundancy, so that it provided a new approach for the clinical elastic registration of CBCT and Planning CT rapidly and accurately.
Algorithms ; Cone-Beam Computed Tomography ; Humans ; Radiotherapy ; methods ; Radiotherapy Planning, Computer-Assisted

OBJECTIVE: To summarize clinical experience of application of argon knife under electronic bronchoscope in the management of pediatric glottic and subglottic diseases. METHOD: Reports in the literature were reviewed. Outcome and prognosis of 4 cases with pediatric glottic and subglottic diseases managed with argon beam coagulator technique in Shanghai children's Medical Center since 2011 were retrospectively analyzed. RESULT: Granulation tissue hyperplasia in 3 cases with subglottic lesions did not recur after surgery. Scarring or stenosis were not found in the airway. Intubation of the trachea and tube of tracheotomy was pulled out successfully in all cases, restoring normal breathing. No lesion recurrence was found in 1 case with squamous cell moderate atypical hyperplasia one month after the surgery. CONCLUSION Electronic bronchoscope has advantages of clear image, fine and soft lens body, optional bending, angle conversion, accurate positioning. And the argon knife with small head diameter can pass the pediatric supraglottic. It can be manipulated precisely with short operation time and no damage to surrounding normal tissues. Its worth in popularization and application of management for with glottic and subglottie disease in pediatric patients.
Adolescent ; Argon ; therapeutic use ; Bronchoscopes ; Child ; China ; Cicatrix ; Humans ; Hyperplasia ; Intubation, Intratracheal ; methods ; Laryngeal Diseases ; surgery ; Lasers, Gas ; therapeutic use ; Neoplasm Recurrence, Local ; Prognosis ; Retrospective Studies ; Tracheotomy ; instrumentation

Objective Using Eclipse and Pinnacle3 V 7.4f treatment planning sytems (TPS) for dose calculation of the CT images of simulation phantom,patients and homogeneous organization phantom,to compare the differences between the two TPS for the calculation of non-uniform organizations.Methods For the CT images of simulation phantom,patients and homogeneous organization phantom,the calculating results between the two TPS were compared,including the common used clinical indexes of V20 and V30 of the lung,D95 of the planning target volume,the doses of the ISO and eight points of interest inside ISO slice.Resuits For simulation phantom and patients,although the calculating differences of the isocenter doses between the two TPS were small,the differences of other indicators were large.For example,when using secondary collimator irradiation,the maximal D95 difference of planning target volume reached 10.17%for patients and 4.64%for simulation phantom.When using muhileaf collimator irradiation,the maximal D95 difference reached 10.74%for patients and 5.66%for simulation phantom.Sometimes the dose differences of points 1-4 at the edge of planning target volume were more than 10%.In addition,the V30 differences of the lung were large too.But for the homogeneous organization phantom,the calculating differences were small.Conclusions The calculating differences between the two TPS are less for simulation phantom than for patients,and more for simulation phantom and patients than for homogeneous organization phantom.

ObjectiveTo study the efficacy of using multileaf collimators with different position and different degree in the treatment of nasopharyngeal carcinoma (NPC) using intensity-modulated radiotherapy techniques.Methods Ten patients withNPC were administered andanalyzed.Thepenumbra characteristics, dose of target, and radiation conformal indexes (CI) of mode T1 and mode T2 were measured and compared using dose volume histogram generated by Varian Eclipse three-dimensional planning computer system. Mode T1 :The angles of seven coplanar beams were 0°, 52°, 106°, 160°, 212°, 258°and 308°,respectively. There were no restriction on the position and degree of multileaf collimators. Parameters were set and optimized. Mode T2 :The beam angles and the parameters were as same as mode T1. According to the actual situations, the position and the degree of the multileaf collimators were changed. Then thedose optimization was performed. Results Target dose coverage in both mode T1 and T2 could be clinically accepted, and the CI were 0. 82 and 0. 83(t = -0. 25, P =0. 815). The maximum dose reductions in the lens, eyes, optic nerves and corneas were 28. 7% (t = 4. 80, P = 0. 000), 2. 7% (t = 2. 99, P = 0. 021),1.4%(t= 1.05,P=0.032), and 30.5% (t=2.99,P=0. 020), respectively. However, the mean dose and V35 of the parotid were increased by 0. 6% (t = - 2. 82, P = 0. 043) and 9.9% (t = - 2. 05, P =0. 038). ConclusionsOpimization of multileaf collimators can reduce the scattering and leaking rays. Compared with mode T1 ,controlling the position and degree of multileaf collimators could reduce the radiation dose to the eyes and optic-nerves, especially to the lens.

Objective To assess the feasibility for the automated treatment planning verification system Mobius3D (M3D) to perform an independent 3D dose calculation in intensity-modulated radiotherapy (IMRT) for cervical cancer.Methods Twenty patients with cervical cancer were randomly selected.With treatment planning systems (Pinnacle,Version 9.2;Eclipse,Version 13.5),all IMRT plans were divided into 7 fields to meet the dosimetric goals.The optimized plans were exported to the M3D server.The percentage differences in the volume of region of interest (ROI) and the dose calculation of target volume and organ at risk (OAR) were evaluated for the two treatment planning systems,and theγ passing rate was used to assess the accuracy of M3D calculation.Results The difference in the volume of ROI for Pinnacle 9.2 to M3D was less than that for Eclipse 13.5 to M3D,with maximum differences of 0.22％±0.69％ and 3.5％±1.89％ for Pinnacle 9.2 and Eclipse 13.5,respectively.The differences in the dose calculation of target volume and OAR for the two treatment planning systems to M3D were within ± 1％.After recalculating by M3D,the dose difference between Pinnacle 9.2 and M3D was smaller than that between Eclipse 13.5 and M3D,but the mean differences were all within ±3％.The γ passing rates for target volume and OAR were more than 95％ on average.Conclusions The method of utilizing the automated treatment planning verification system to validate the accuracy of plans is convenient.It can be used as a secondary check tool to improve accuracy in IMRT dose calculation.

BACKGROUND:Previous studies from Shaanxi Institute of Ophthalmology have shown that ostrich cornea has the advantages to be developed into the alternatives of human corneal material.
OBJECTIVE:To determine the potential toxic effects of ostrich corneal stromal scaffold on cel s.
METHODS:Cel culture methods were used to culture L-929 cel s in the extracts of ostrich acel ular corneal
stroma which was dried and dehydrated. 3-(4,5)-Dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide assay was used to evaluate the growth and proliferation of cel s after cultured for 1, 2 and 3 days.
RESULTS AND CONCLUSION:After the cel s were cultured in the extracts of ostrich acel ular corneal stroma subjected to dryness and dehydration for 1, 3 and 5 days, and the toxicity level of cultured cel s was graded as level 1. The cytotoxicity test was conducted according to the“National Standard of the People's Republic of China GB/T16886.5-2003”. After cultured in the extracts of ostrich acel ular corneal stroma, a smal number of cel s were round in shape and loosely adherent without intracytoplasmic granules, and cel lysis could be observed
occasional y. The results of 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide assay showed that
the ostrich acel ular corneal stromal scaffold which was dried and dehydrated had level 1 of cytotoxicity and could be considered as a qualified material.

Objective To evaluate the dose distribution of target volume and normal tissues in forward intensity modulated radiotherapy (fIMRT) and inverse intensity modulated radiotherapy (iIMRT) modes for breast cancer after radical mastectomy.Methods Both fIMRT and iIMRT plans were developed for 10 patients with breast cancer after radical mastectomy.On each patient's CT images the supraclavicular area, chest wall, and internal mammary area were delineated.The prescription dose was 50 Gyin 25fractions.In the fIMRT plan X-ray irradiation at the dose of 6 MV was adopted for the supraclavicular and the chest wall areas and electron irradiation at the dose of 9 - 12 MeV was adopted for the internal mammary area, and the doses of cold and hot spots were adjusted according to the fitting doses of these 3 regions.In the iIMRT plan the supraclavicular area, chest wall, and internal mammary area were taken asa whole target, 6 MV X-rays was used, and inverse optimal design was performed.The dose distribution oftarget volume and normal tissues, conformal index (CI) , and heterogeneous index (HI) , and acceleratormonitor unit (MU) were analyzed using dose-volume histogram (DVH)for the two intensity modulated modes.Results The maximum dose of PTV of the iIMRT plan was significantly lower than that of the fIMRT plan(t = -3.23,P ＜0.05), the minimum dose and V95% of PTV of the iIMRT were significantly higher than those of the fIMRT plan(t = 4.08, -2.69, both P ＜0.05).The CI level of the iIMRT plan was significantly higher than that of the fIMRT plan and the HI level of the iIMRT plan was significantly lower than that of the fIMRT plan (t = -3.13, 2.74, both P ＜0.05).There were not significant differences in V10, V20, V25, V30, and Dmean of the ipsilateral lung between these 2 groups.However, the V15 of ipsilateral lung of the iIMRT group was significantly lower by 4.2% than that of the fIMRT group (t= 3.2, P ＜ 0.05).There were not significant differences in the mean dose (Dmean) and V30 of heart, and Dmean of contralateral lung and contralateral breast between these 2 groups.Conclusions Compared with fIMRT, the iIMRT plan results in more PTV coverage, higher conformity index, and more homogeneous dose distribution, with lower dose upon the lung at the affected side, and better protection of the contralateral lung, heart, and breast.

Objective To investigate the feasibility of online and offline cone-beam CT (CBCT) guided radiotherapy for lung cancer. Methods Fourteen patients with lung tumor treated by three-dimen-sional conformal radiotherapy were investigated. Online kV CBCT scan,image registration and setup correc-tion were performed before and immediately after radiotherapy. CBCT online-guided correction data were used to calculate the population-based CTV-PTV margins under the condition of non-correction and correction in every fraction respectively. The numbers of initial images and the population-based CTV-PTV margins af-ter the offline compensation of the system setup error were evaluated with the permission of 0.5 mm and 1.5 mm maximal residue error,respectively. Results Under the condition of non-correction,the required mar-gins for total error were 5.7 mm,8.0 mm and 7.8 mm in the left-right(x axis) ,cranio-caudal(y axis) and anterior-posterior(z axis) directions, respectively. When the tumor was corrected in every fraction, the re-quired margins for intra-fraction error were 2.4 mm,2.4 mm and 2.3 mm in x,y and z axes, respectively. To correct the systematic setup error,9 sets of CBCT images for 3.3 mm,3.7 mm and 3.6 mm PTV margins, and 7 sets of CBCT images for 3.9 mm,4.3 mm and 4.3 mm PTV margins in x,y and z axes were necessary when 0. 5 mm and 1.5 mm maximal residue errosr were permited respectively. Conclusions Both of the online CBCT correction and the offline adaptive correction can markedly reduce the impact of setup error and reduce the required PTV margins accordingly. It is feasible to deliver the online and offline image guided ra-diation for patients with lung tumor.

Objective To evaluate the dosimetric imnpact of the fixed position of two-degrade collimator in the treatment of breast cancer after radical mastectomy using intensity-modulated radiotherapy (IMRT) technique.Methods A total of ten patients with breast cancer were treated with radical mastectomy and radiotherapy sequaciously involving the supraclavicular region and the chest wall.Two different IMRT treatment plans were designed for each patient:0°,40° and two tangential field.There was no restriction on the position of two-degrade collimator(IMRT-1) (P ＞ 0.05).The beam angles and the parameters were as same as IMRT-1,but fixed the position of the two-degrade collimator of 0° and 40° at the inferior border of the supraclavicular (IMRT-2).The dose distribution of target volume and normal tissues,conformal index (CI),and heterogeneous index (HI) were estimated with the dose volume histogram (DVH) for the two intensity modulated modes.Results The CI were 0.79 and 0.73 (Z =-2.316,P＜0.05),and the HI of the IMRT-2 plans was not different from IMRT-1 (P ＞ 0.05).Considering the dose volunes of the ipsilateral lung in two plans,the values of V5,V10,D of IMRT-2 were significantly less than those of IMRT-1 (Z =-2.805,-2.812,-2.521,P ＜ 0.05).Meanwhile,the D of the contralateral lung,D of heart and D of the contralateral breast from the IMRT-2 were all lower than those oflMRT-1 (Z=-2.666,-2.701,-2.310,P＜0.05).There was no significant difference in the values of V20,V30 of the ipsilateral lung,V30 of heart and between IMRT-1 and IMRT-2 (P ＞0.05).Conclusions Compared with IMRT-1,IMRT-2 with fixed position of the two-degrade collimator could significantly reduce the low dose region of the lung and heart.It may be used as an effective alternative for breast cancer after radical mastectomy irradiation.

Objective To evaluate the anatomic changes and dosimetric variations of patients with nasopharyngeal carcinoma (NPC) during the course of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) by comparison of the dosimetric differences with or without replanning.Methods Twelve cases with NPC treated with SIB-IMRT underwent repeated CT scans after 20- 25 fractions of the initiation of therapy.The original treatment plan ( Plan1 ) based on the first CT scan ( CT1 ) and the second IMRT plan (Plan 2) based on the second CT scan (CT2) were calculated with an inverse planning system (Pinnacle3,Philips Medical System).In addition,the hybrid IMRT plan,Planl (CT2),was generated by deformable registration with MIMVISTA software,and the doses in Plan 1 ( CT1 ) and Plan 2 ( CT2 ) were accumulated based on CT2.The dosimetric differences were compared among the Plan 1 ( CT1 ),Plan 1 (CT2) and Plan 1 + 2(CT2).Results Compared with CT1,the mean volumes of the right and left parotid glands in the CT2 were significantly smaller by ( 24.6 ± 11.9 ) ％ and ( 35.1 ± 20.1 ) ％,respectively.Compared with Plan 1 ( CT1 ),the dose received by 95％ of the target ( D9s ) to PGTV,PTV1 and PTV2,and mean dose (D ) to PGTV,and PTV2 were all significantly lower in the Plan 1 (CT2),indicating that the doses to targets decreased without replanning.With repeated CT and replanning after 25 fractions as shown in Plan 1 + 2 (CT2),the doses to targets would be improved.The doses to normal tissue were increased without replanning,although no statistical significance was observed.In 5 of 12 cases,the doses to the spinal cord and brainstem exceeded the constraint without replanning,while the corresponding values decreased with replanning.Conclusions During the course of IMRT for cases with NPC,the volumes of the targets and parotid glands decrease significantly.Mid-treatment CT scanning and replanning should be recommended to ensure adequate doses to the targets and safe doses to the normal tissues.