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

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.

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 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.

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.

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 To compare and analyze the dosimetric characteristics of the intensity-modulated arc therapy (RapidArc) combined with active breathing coordinator (ABC) in the thoracic esophageal carcinoma radiation therapy. Methods Ten thoracic esophageal carcinoma patients undergoing radiotherapy were selected for this study.The CT simulations were performed under three breath patterns respectively:moderate deep inspiration breath-hold (mDIBH) with ABC aid; Set the trigger threshold to 80％ of the peak of the respiration curve; and free breathing (FB).Based on the corresponding CT image sets,three treatment plans were generated for each patient respectively:Arc-ABC( three small arcs),ArcFB (consisted of two coplanar full arcs) and IMRT-FB plan.The following dosimetric parameters were compared among different plans:D2％,D98％,V95,homogeneity index ( HI),conformal index ( CI ) the percentage of volume receiving dose of over x Gy (Vx),monitor unit (MU),control points and treatment time.Results The planning target volume ( PTV ) of FB was 376 cm3 which decreased to 260 cm3 after using ABC.For mDIBH and FB patients,the total lung volumes were 5964.6 cm3(35％ more than FB) and 3838.8 cm3 respectively; the heart volumes were 524.4 cm3 and 642.7 cm3 respectively. No significant difference was observed among Arc-ABC,IMRT-FB and Arc-FB in terms of D2,D98,V95,CI and HI.For Arc-ABC plans,there were significant decreases of radiation dose in total-lung's V10,V20,V30,V40 and mean lung dose ( F =4.38,5.34,4.07,3.89,4.28,P ＜0.05).Various dose decreases of heart V20,V3,V40,Dmean and spinal cord Dmax were observed,yet no statistically significant difference existed.The MUs and total control points of Arc-ABC plans were significantly lower than other plans ( F =26.86,12.56,P ＜ 0.05 ).Conclusions When thoracic esophageal carcinoma patients were treated with radiotherapy,the combined utilization of RapidArc and ABC can potentially decrease the volume of irradiated lung yet escalate the dose in target.

Objective To assess mutations in the ALDH3A2 gene in two patients with Sj(o)gren-Larsson syndrome manifesting primarily as congenital ichthyosis,mental retardation and spastic paraplegia.Methods Two patients,a 2-year-old girl and a 1.5-year-old boy,with Sj(o)gren-Larsson syndrome were included in this study.None of their family members suffered from this disease.Peripheral blood samples were collected from the two patients,their family members (an elder brother and both parents),and 100 unrelated healthy controls.DNA was extracted from the blood samples,and subjected to PCR for the amplification of 10 encoding exons and their flanking sequences of the ALDH3A2 gene followed by DNA sequencing.Results A homozygous missense mutation c.325G ＞ A,which leads to the substitution of glycine by arginine at position 109,was detected in the ALDH3A2 gene of patient 1,whose parents and elder brother were heterozygous carriers of this mutation.The patient 2 carried compound heterozygous mutations,including c.1157A ＞ G (p.Asn386Ser) inherited from his father and c.1294A ＞ T (p.Arg432X) inherited from his mother.None of these mutations was detected in the unrelated healthy controls.Conclusion The homozygous mutation p.Gly109Arg and compound heterozygous mutations p.Asn386Ser and p.Arg432X present in these patients may be associated with clinical phenotypes of Sj(o)grenLarsson syndrome.

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 evaluate the accumulated doses to normal tissues and organs at risks (OARs) of patients with lung cancer in radiotherapy plans by using the deformable registration method,and make comparison with the empirical calculation method.Methods Ten patients with lung cancer were analyzed retrospectively.3D-CRT or IMRT plans were designed before treatment. CT to simulator was rescanned and the same treatment plan was redesigned during radiotherapy. Based on the deformable registration method,the Mimvista software was used to calculate the accumulated doses to normal tissues and OARs in two CT images respectively.The empirical estimation algorithm was calculated by the linear relationship between the fractions and the total prescribed dose.Results The target coverage of patients had no significant difference in two plans.There were no significant differences in all the dose volume parameters for normal tissues and OARs,except the mean dose to right lung( t =2.98,P ＜ 0.05 ) when the the same plan was conducted in position-setting and reposition CT images.Conclusions The empirical estimation for the accumulated dose could be used to evaluate the dose and volume parameters for normal tissues and OARs in lung cancer by the same plan.