10.3969/j.issn.1000-3606.2013.06.004

Objective To scrutinize the positioning accuracy and reproducibility of the cone-beam computed tomography system in combination with the six-degree couch table (Hexapod Robot Treatment Table, HRTT). Methods The mechanical stability of the X-ray volume imaging (XVI) system was tested,in terms of the reproducibility. And the influence of the moveable parts, including the KV panel and the source arm, on the accuracy of the XVI image registration was analyzed. The accuracy between the bone and grey value registration was compared using a head-and-neck phantom. The accuracy of the HRTT for translational, rotational, and a combination of translational and rotational corrections was investigated in consecutive measurements. Results The performance of XVI system itself was stable with translational and rotational error of below 0. 4 mm and below 0. 3°, respectively. The mean position accuracy of the XVI system in combination with the HRTT summarized over all measurements was below 0. 6 mm and below 0. 4° for translational and rotational corrections, respectively. The grey value match was more accurate than the bone match. Conclusions The XVI image acquisition and registration procedure were highly reproducible.Both translational and rotational positioning errors can be corrected very precisely with the HRTT. The HRTT is therefore well suited to complement CBCT to take full advantage of position correction in six degrees of freedom for image guided radiotherapy.

Objective To evaluate the autocontouring accuracy using the atlas-based autosegmentation of CT images for head-and-neck cancer.Methods Ten head and neck patients with contours were selected.Two groups of autocontouring atlas were tested,the first group was for patients with own atlas,for the second group we tested the autocontouring of eight patients with other two patients atlas.Dice similarity coefficient (DSC) and overlap index (OI) were introduced to evaluate the autocontours,and the discrepancy between the two groups was evaluated through paired t-test.Results Both the DSC and OIof all the organs in the first group were ＞0.80,the result of mandible was the highest ( ＞0.91 ),the DSC of the gross tumor volume (GTV) was the lowest (0.81 ),the OI of the GTV was 0.82,and the DSC and OI of the clinical target volume (node) were 0.82 and 0,79,respectively.Only the risk organ was delineated in the second group,and spinal cord and brain stem were combined to analyze.All the DSC was about 0.70,and the DSC and OI of mandible were higher than the others,which was due to its bone anatomy.The accuracy in the second group was significantly lower than that of the first group ( t =3.24 - 8.26,P =0.014 -0.000),except the right parotid (t=2.08,P=0.075).Conclusions Automatic segmentation generates contours of sufficient accuracy for adaptive planning intensity-modulated radiotherapy (IMRT) to accommodate anatomic changes during treatment.For convention planning IMRT normal structure auto-contouring,it need to select more standard atlas in order to acquire a satisfied autocontours.

Objective To test and evaluate the geometric accuracy of delineation of organs at risk ( OARs) in head and neck cancer using an atlas?based autosegmentation ( ABAS) software. Methods The atlases for the ABAS software was generated using images from 40 patients with head and neck cancer undergoing intensity?modulated radiotherapy. The software was tested in 40 new patients. Automatic delineation of OARs was carried out on computed tomography images by single?( one to one ) and multi?template ( ten to one) approaches. In order to evaluate the feasibility of the automatic delineation in clinical application, differences in volume (ΔV%), position (Δx,Δy, andΔz), conformability (sensitivity ( Se ), specificity ( Sp ) , and dice similarity coefficient ( DSC) ) , and delineation time were assessed between the automatic and manual delineation. The comparison between the two automatic delineation approaches was made by paried t test. Results For all OARs, the multi?template automatic delineation achieved a significantly smaller mean ΔV% value and a significantly larger mean DSC value than the single?template automatic delineation (-0.02%± 0?29% vs. -0.16%± 0?41%, P<0?05;0.74± 0?16 vs. 0.68± 0?20, P<0?05);the position differences between two automatic delineation approaches were less than 0?4 cm in all three directions except for the temporal lobe, lower jaw, and spinal cord;in the receiver operating characteristic curve defined by Se versus 1-Sp , the data points were all within the first quadrant except for the optic nerve and chiasm;automatic delineation saved 42%?72% of time compared with manual delineation. Conclusions The ABAS software achieves satisfactory results of automatic delineation for most of OARs in patients with head and neck cancer. The multi?template automatic delineation, particularly, has better outcomes than the single?template one. In addition, it greatly shortens the time the clinicians spend on delineation of OARs.

Objective To investigate and analyze the positioning accuracy of three imaging modalities utilized in image-guided radiotherapy (IGRT):electronic portal imaging device ( EPID),kV portal image (kV planar) and the kV cone beam computed tomography (CBCT).Methods 25 groups of setup errors were simulated on the phantom images through treatment planning system. Digitally reconstructed radiographs (DRRs) were constructed from the CT data which were subsequently used as references to register the EPID and kV planar images acquired at the original position.In addition,the reconstructed 3D-CT images were used to register the CBCT images.Finally,the setup errors using several registration methods were measured to investigate and compare the accuracies of the three imaging modalities used for patient setup.Results 675 groups of residual errors were analyzed.All combinations of imaging modalities and registration method were found to be accurate.The mean residual errors in three directions were less than 1 mm.The method based on grey value match of CBCT images was found as the most accurate with an uncertainty below 0.1 mm.When the manual match was used,the performance of kV planar was more accurate than that of EPID (residual error ＜ 0.65 mm).If automatic registration was applied,kV planar generated similar results as EPID did. Conclusions The three available imaging modalities and their corresponding registration methods are all competent for the clinical application of IGRT in our department.Considering the image quality,radiation dose and the accuracy of registration,CBCT has the priority on 1GRT followed by the kV planar.

Objective To compare the static intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT) for mid and upper thoracic esophageal cancer.Method The data of twenty esophageal cancer patients were retrospectively re-planned with VMAT(single arc and double arcs) modality using Pinnacle treatment plan system.Five of these patients were selected again to simulate single arc plans with different segment intervals (4°,3°,2°) and re-planned on other treatment planning systems (Monaco and MasterPlan).Differences of dose distribution and treatment parameters were compared.Results In comparison to IMRT and single-VMAT (S-VMAT),Double-VMAT (D-VMAT) significantly improves the dosimetric parameters for targets(P ＜ 0.05),dose homogeneity(P ＜ 0.05) and conformity(P ＜ 0.05).Though VMAT plans were slightly better than IMRT in reducing the doses to the organs at risk (OARs),no advantage was observed in the low-dose protection of lung and E-P (P ＜ 0.05).For the VMAT plans with different segment intervals,lower OAR doses were observed using an interval of 2°(P ＜ 0.05),except for the mean dose of the heart.For the VMAT plans on different treatment planning systems,Monaco-based plans protected OARs better (P ＜ 0.05).The number of monitor units (MU) and treatment time were less in VMAT cases.Conclusions VMAT plans perform better in target coverage,dose homogeneity and conformity,and can reduce the radiation dose to the spinal cord,lungs,heart and other normal tissue than IMRT plans.The VMAT plan quality could be further improved by using double arcs and smaller segment interval.Monaco-based plans provide better OAR protections under the same conditions of physical and optimization parameters.

Objective To investigate the diagnostic significance of basophil activation test (B A T) in ana-phylaxis to non-ionic contrast media through testing the content of CD 63, m ast cell-carboxypeptidase A 3 (M C-CPA 3), and term inal com plem ent com plex SC5b-9 of the individuals by testing their levels in the norm al im m une group and the anaphylaxis groups to β-lactam drugs and non-ionic contrast media. Methods The CD 63 expression of basophilic granulocyte in blood w as detected by flow cytom etry. The levels of M C-CPA 3 in blood serum and SC5b-9 in blood plasm a w ere detected by ELISA . Results The CD 63 expression of basophilic granulocyte in blood, the levels of M C-CPA 3 and SC5b-9 of anaphylaxis to non-ionic contrast media and β-lactam drugs w ere significantly higher than that in norm al im m une group (P<0.05). Conclusion There is activation of basophilic granulocytes, m ast cells and com plem ent system in anaphylaxis to non-ionic contrast media. B A Tcan be used to diagnose the anaphylaxis to non-ionic contrast media.

Objective In order to understand which kind of function genes play an important role for es-timating wound age, the variation of difference genes’ mRNA expression were compared after injury. Methods T he mRNA expression levels of seven candidate genes (ICAM-1, NF-κB, MX2, MT1, MT2, sTnI, and Cox6c) were analyzed in contused rat skeletal muscle at different time points using real-time fluorescent quantitative PC R (R T-qPC R ). T he rawC t values were normalized relative to that of RPL32 mRNA , and converted to standard C t values. A t each time point after injury, the standard deviations (SD ) of the standard C t values were calculated by SPSS. Results T he expression trends of the seven genes were all found to be related to wound age, but there were lower variation coefficients and greater reliability of sTnI and Cox6c when compared with other genes. Conclusion T he genes encoding struc-tural proteins or proteins that performbasic functions can be suitable for wound age estimation.

Objective To compare the dosimetric difference among plans designed by 4-field,6-field TomoDirect and TomoHelical techniques in Tomotherapy system for left-breast cancer patients with radiotherapy after breast-conserving surgery.Method A total of 16 patients with left-breast cancer following breast-conserving surgery and intensity-modulated radiation therapy were enrolled in this retrospective study.The 4-field TomoDirect (TD4),6-field TomoDirect (TD6),and TomoHelical (TH) techniques were applied to design simulation plans in tomotherapy system for each patient,respectively.The differences of dose distribution and treatment parameters were analyzed in this study.Results Three plans all met the clinical requirement.Thereinto,TD4 was superior to TH in the dose limitation of organs at risk (OARs),especially the max dose of cord and right-breast,thc 5 Gy radiation volume of lung,and the mean dose of heart(F =595.60,129.24,60.44,65.37,P ＜ 0.05),but inferior to TH in dose homogeneity (HI) and conformity (CI) (F =2.78,60.93,P ＜ 0.05).However,TD6 improved TD4's HI and CI when delivered the lower OARs dose compared to TH.Meanwhile,the number of monitor units was less in TD technique and reduced the treatment times (F =24.89,3.75,P ＜ O.05).Conclusions For the radiotherapy of left-breast cancer patients after breast-conserving surgery,TD6 technique appeared to be superior,with the lower radiation dose of OARs compared to TH technique,and the better target's HI and CI in comparison with TD4 technique,especially in patients with early stage breast cancer.

Objective To investigate the correlation between the CYP17 gene polymorphisms and hyperandrogenemia(HA) in Uygur women patients with polycystic ovary syndrome (PCOS ) .Methods 59 Uygur patients with PCOS were selected as the Uygur PCOS group and re-divided into the Uygur PCOS complicating HA group and Uygur PCOS non-complicating HA group . Meanwhile 18 Han patients with PCOS complicating HA were selected as the Han PCOS group .The polymerasechain reaction-restrictive fragment length polymorphism method was used to examine the basic group polymorphisms in the promoter region of CYP17 gene .Then the correlation between basic group locus polymorphism and Uygur PCOS complicating HA was analyzed .Results There was no statistically significant difference between TT ,TC and CC genotypes and T ,C allele frequencies in the Uygur PCOS non-complicating HA group and Uygur PCOS complicating HA group (P＞ 0 .05) .There was no statistically significant difference between TT ,TC and CC genotypes and T ,C allele frequencies in the Uygur PCOS complicating HA group and Han P-COS group(P＞0 .05) .The serum testosterone level in TT ,TC and CC genotypes patients of the Uygur PCOS complicating HA group was significantly higher than that in the Uygur PCOS non-complicating HA group(P＜0 .05) .Serum testosterone level had no statistically significant difference between TC ,CC genotypes and TT genotype patients of Uygur PCOS group(P＞0 .05) .Conclusion The distribution frequency of CYP17 genotypes does not increase the risk suffering from HA in Uygur women .Single nucleotide polymorphism in CYP17 gene promoter region had no obvious correlation with Uygur PCOS complicating HA occurrence .