Objective To perform a systematic review and Meta-analysis on volumetric and dosimetric changes in target volumes and organs at risk (OARs) in adaptive radiotherapy (ART) for patients with head and neck cancer (HNC),and to investigate the role of ART in the treatment of HNC.Methods Literature retrieval was performed to include related studies,and the parameters of primary tumor,GTV-T and GTV-N,parotid volume,D95 and Dmean of target volumes,Dmean of ipsilateral and contralateral parotid volume (I-PG and C-PG),and Dmax of the spinal cord and brainstem.Results A total of 17 studies involving 336 patients were included in the meta-analysis.Primary tumor and parotid volume changed significantly.The volumes of GTV-T,GTV-N,and I-PG were significantly reduced during the 15-20th radiotherapy and after the 20th radiotherapy (P＜0.05),and the C-PG was significantly reduced after the 20th radiotherapy (P=0.004).The analysis of actual dose showed that the D95 and Dmean of primary tumor showed no significant differences,and during the 15-20th radiotherapy,the Dmax of the spinal cord was increased by 2.26 Gy (P=0.000),while the Dmax of the brainstem showed no significant changes before the 20th radiotherapy and was increased by 1.78 Gy after the 25th radiotherapy (P=0.020).In addition,the Dmean of I-PG was increased by 2 Gy during the 20-25th radiotherapy (P =0.0001),and the D of C-PG was increased before the 20th radiotherapy and showed no significant changes after the 25thradiotherapy (P=0.110).The dosimetric analysis of ART showed that the Dmax of the spinal cord and brainstem was reduced significantly (spinal cord:MD =-2.15,95％ CI-3.12 to-1.18,P=0.000;brainstem:MD =-2.20,95％ CI-3.32 to-1.09,P=0.000).The Dmean of I-PG was reduced by about 3.5 Gy,and the sensitivity analysis revealed that the results of Dmean of C-PG were unstable.Conclusions The volumes of primary tumors and parotid glands change significantly,and the actual doses of OARs (Dmax of the spinal cord and brainstem and Dmean of the parotid glands) significantly increase,while the doses of GTV-T and GTV-N show no significant changes.ART can effectively protect the OARs,and patients with locally advanced HNC who receive concurrent chemoradiotherapy can obtain good dose gains from ART plan performed during the 15-20th radiotherapy and at about the 25th radiotherapy.

Objective To compare the effects of positioning robustness on dose distribution between intensity-modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for head and neck tumor,and to evaluate their needs for image-based guidance.Methods Thirty patients with nasopharyngeal carcinoma undergoing IMRT were enrolled as subjects.The VMAT plans were designed according to the clinical dosimetric requirements and the dose calculation was made by the AAA method.For the two plans in each patient,the isocenters were shifted by ±1.0,±3.0,and ±5.0 mm along the original x,y,and z axes to simulate the impacts of positioning errors in left-right (LR),superior-inferior (SI),and anterior-posterior (AP) directions,respectively,on dose distribution.The dose-volume histogram parameters were analyzed in 60 references and 1080 re-calculated plans.Comparison was made by paired t-test.Results When the error was 1 mm,the average deviations of gross tumor volume (GTV) D98,clinical target volume (CTV) D95 and heterogeneity index,and planning gross tumor volume (PGTV) V95 were＜0.5％.When the error was 3 mm,the average dose deviations of GTV and CTV were＜1.0％ and significantly larger in VMAT than in IMRT;the average dose deviation of PGTV was large (GTV D98,P=0.00;CTV D95,P=0.00);the average deviations of PGTVnxV95 and PGTVndV95 were significantly smaller in IMRT than in VMAT (1.64％vs.1.95％,P=0.01;1.73％ vs.2.63％,P=0.00).The deviations of parameters became larger with the increasing positioning error and were significantly larger in VMAT than in IMRT (GTV D98,P=0.00;CTV D95,P=0.00;CTV HI;P=0.00;PGTV V95;P=0.01).Compared with the target volume,Dmax to the spinal cord and brain stem had larger deviations.However,there were no significant differences in Dmax to the spinal cord and brain stem between IMRT and VMAT.Conclusions The IMRT and VMAT plans are both robust when the positioning error is small (＜3 mm).Compared with IMRT,VAMT is more sensitive to the positioning error,mainly in the target volume.The difference between the two plans becomes larger with the increasing positioning error.An increase in the frequency of image-based guidance is recommended for patients undergoing VMAT.

AIM:To compare the effects of different histogram enhancement algorithms on improving the quality of MRI image.METHODS:Three processing algorithms,including histogram equalization,adaptive histogram equalization and histogram specification,were applied to enhance a MRI cervical spine T2-weighted image based on programming software interactive data language.The capability of representation of details in dark area and the level of noise were evaluated by means of peak signal to noise ratio and image information entropy.RESULTS:Histogram equalization cannot enhance the details in dark region obviously,but decline the contrast of whole image;adaptive histogram equalization can improve details but enlarge noise and engender shadow at edges simultaneously;histogram specification can choose the type of histogram function to match;it reveals the details in dark area sufficiently,and there is the lowest level of noise among these three algorithms.CONCLUSION:MRI cervical spine T2-weighted image processing with different algorithms of histogram enhancement,histogram specification is more outstanding than histogram equalization and adaptive histogram equalization in the representation of details and the low-level of noise.

Objective To investigate the consistency in the measurement of epicardial adipose tissue (EAT)volume using non-ECG-gated CT and ECG-gated CT.Methods ECG-gated CT and non-ECG-gated CT examinations were obtained in 104 subjects. The ECG-gated group was outlined the epicardium by an associate chief physician with a hand-painted method,the CT value of quan-titative adipose tissue was ranged from -30 HU to -250 HU.The non-ECG-gated group was outlined the epicardium by two asso-ciate chief physicians,A and B;The two CT values were ranged from -20 HU to -250 HU and from -30 HU to -250 HU,re-spectively.The measurement results of two groups were compared for the analysis of the relationship between EAT volume and cor-onary atherosclerosis.Results After the employment of CT value ranging from -20 HU to -250 HU for non-ECG-gated group, the measurement result was well consistent with ECG-gated group.The measurement results obtained by two associate chief physi-cians using the same range of CT value were in a good consistency.The EAT volumes obtained by various measurements were all correlated to the occurrence of coronary atherosclerosis.Conclusion After adjusting the range of CT value,two methods were in a good consistency.Non-ECG-gated CT measurement of EAT volume is easy to operate,which has a better practical value.

OBJECTIVE: To analyze recent developments in image texture research both from methodology and from medical image analysis. DATA SOURCE: With the key words of "medical image, texture research, image analysis, application", we retrieved PubMed database (http://www.ncbi.nlm.nih.gov/sites/entrez/), ScienceDirecr database (http://www.sciencedirect.com/) from 1983 to 2009 and CNKI database (http://www.cnki.net/) from 2004 to 2009. DATA SELECTION: Original research thesis, and reviews with clear opinion, sufficient data and reliable conclusion were included. Repetitive studies and studies concerning unrelated to the objective were excluded. MAIN OUTCOME MEASURES: A total 104 literatures were selected, including 10 Chinese literatures and 94 English literatures. These literatures were primarily collected by reading titles and abstracts. A total of 33 literatures with unrelated objective, 18 literatures with repetitive studies were excluded. Finally, 53 Chinese and English literatures were included for further analysis. RESULTS: Primary methods used in texture analysis are structural, statistical, model-based and transform-based-method. When we are interested in identifying texture primitives and their distribution to analyze regular texture, structural approaches are suited. Characteristics of texture like smoothness and coarseness are well analyzed by statistical approaches. Model-based-method is based on the construction of an image model that can be used not only to describe texture, but also to synthesize it. Digital features of texture are got by using some signal processing theories in transformation domain. Texture applications have been widely used in medical imaging domain. CONCLUSION: Because of the specific and complication of medical image and texture, not all texture measure can be used for medical image analysis. One of the development directions of medical image texture research is how to integrate and educe advantages of different methods to fully extract texture features and exactly attribute medical image texture and the relation between its changes and pathological state, resulting in an important component of computer-aided diagnosis.

Objective To investigate the dosimetric comparison of target volumes and organs at risk (OAR) between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for esophageal cancer by a meta-analysis.Methods A literature search was performed to collect the clinical studies on dosimetric comparison between VMAT and IMRT.The primary endpoints of interest were dosimetric parameters of target volumes and OAR, number of monitor units (MUs), and treatment time (TT).Results A total of 17 studies involving 323 patients were included in this meta-analysis.When the total dose was>50.4 Gy, VMAT showed significantly lower mean dose (Dmean) of gross tumor volume (GTV) and maximum dose (Dmax) of planning target volume (PTV) than IMRT (P=0.009;P=0.039).There were no significant differences in Dmean, V30, and V40 of the heart, Dmax of the spinal cord, and V5, V10, and Dmean of the lung between VMAT and IMRT (P>0.05).VMAT showed significantly lower V15, V20, and V30 of the lung than IMRT (P=0.001;P=0.000;P=0.023).When the single dose was 1.8 Gy and 2.0 Gy, VMAT showed significantly lower TT (reduced by 323.5 s and 193.7 s) and number of MUs (reduced by 275.4 MU and 134.2 MU) than IMRT (P=0.000 and 0.009;P=0.000 and 0.022).Conclusions VMAT can significantly reduce TT, MUs, irradiation dose to the lung, and the risk of radiation pneumonitis, and improve the utilization rate of equipment.Compared with IMRT, VMAT has no significant advantages in protection of the spinal cord and the heart and dosimetric parameters of target volumes except Dmean of PTV and Dmean and Dmax of GTV when the total dose was ≤50.4 Gy.

Objective To analyze the abnormal region of gray matter and its distribution characteristics in Parkinson's disease (PD) patients with mild cognitive impairment (PD-MCI),and to investigate the structural brain changes which closely related to mild cognitive impairment.Methods 27 PD patients were examined by T1WI three-dimensional brain volume (3D-fast spoiled gradient echo,3D-FSPGR) sequence,and were divided into 2 groups:PD patients with mild cognitive impairment group (PD-MCI group,n＝15) and PD patients without mild cognitive impairment (PD-nMCI group,n=12).Gray matter map in the two groups were analyzed by using voxel based morphometry (VBM) based on SPM5.Results There were significant differences in MMSE and MoCA scores between the two groups (P＜0.01 or 0.05).Compared with PD-nMCI group,gray matter volumes in PD-MCI group were decreased in bilateral mid frontal gyrus,left precentral gyrus,right mid-temporal gyrus,left superior temporal gyrus,transverse temporal gyrus,bilateral lingual gyrus,right cuneus,bilateral insular and right posterior cingutate gyrus.Conclusions Gray matter atrophy in bilateral mid-frontal gyrus,insular and left precentral gyrus is closely related to the mild cognitive impairment in PD patients.

Objective To study the MR performances of finger joints with health subjects and rheumatoid arthritis (RA)patients,and to detect the imaging quality of a custom-made finger coil.Methods Finger coil,extremity coil,flexible surface coil and 3 inch surface coil were used to scan the self-made water phantom with similar T2 WI sequence,then the signal to noise ratio (SNR)on single image was measured for the comparison.The middle finger specimen (1 finger)was used for the research,5 healthy volunteers (8 fingers)and 18 RA patients (22 fingers)were also scanned.Results The SNR of finger coil was over 1.5 times higher than that of the 3 inch surface coil and 4 times higher than that of the extremity coil and flexible surface coil.For the 22 fingers with confirmed RA,synovitis was found in 1 7,joint effusion in 10,bone marrow edema in 5,bone erosion in 7 and tenosynovitis in 6.Conclusion The finger coil has higher SNR.

In this paper are analyzed the disadvantages of CGO-3000 digital subtraction angiography table Operating Box. The authors put forward a communication control scheme between single-chip microcomputer(SCM) and programmable logic controller(PLC). The details of hardware and software of communication are given.
Angiography, Digital Subtraction ; instrumentation ; Equipment Design ; Humans ; Image Processing, Computer-Assisted ; instrumentation ; Microcomputers ; Radiographic Image Enhancement ; instrumentation ; Software

Objective: To compare the dosimetric parameters of target volumes and organs at risk between volumetric-modulated arc therapy (VMAT) and intensity-modulated radiotherapy (IMRT) for left sided breast cancer after breast-conserving surgery by a meta-analysis. Methods: Literature search was performed to include related studies to analyze the dosimetric parameters of target volumes and organs at risk. Results: A total of 11 studies involving 154 patients were included in meta-analysis. There were no significant differences in D_mean, HI of PTV-Whole breast and PTV-Boost. Comparing to IMRT, VMAT increased the conformity index (CI) of PTV-Whole breast (P=0.000) and PTV-Boost (P=0.002). When the mean volume of target volumes was≤634 cm³, there were no significant differences in D_mean, V₅, V₂₀ of the heart and left sided lung, V₃₀ of the heart, D_mean of the right sided lung and breast between VMAT and IMRT.When the mean volume of target volumes was>634 cm³, the D_mean(P=0.037), V₅(P=0.005) and V₂₀(P=0.030) of the heart in IMRT was lower than VMAT, but the V₃₀(P=0.001) of heart in VMAT was lower than IMRT.IMRT showed significantly lower D_mean(P=0.013), V₅(P=0.000), V₂₀(P=0.000) of the left sided lung, and D_mean(P=0.001) of the right sided lung than VMAT.There were no significant differences in D_mean of the right sided breast. Conclusions There were no significant differences in dosimetric parameters of target volumes between VMAT and IMRT.When the mean volume of target volumes was≤634 cm³, there were no significant differences in dosimetric parameters of organs at risk. When the mean volume of target volumes was>634 cm³, IMRT has some advantages in protection of the heart and lung.