We applied Demons and accelerated Demons elastic registration algorithm in radiotherapy cone beam CT (CBCT) images, We provided software support for real-time understanding of organ changes during radiotherapy. We wrote a 3D CBCT image elastic registration program using Matlab software, and we tested and verified the images of two patients with cervical cancer 3D CBCT images for elastic registration, based on the classic Demons algorithm, minimum mean square error (MSE) decreased 59.7%, correlation coefficient (CC) increased 11.0%. While for the accelerated Demons algorithm, MSE decreased 40.1%, CC increased 7.2%. The experimental verification with two methods of Demons algorithm obtained the desired results, but the small difference appeared to be lack of precision, and the total registration time was a little long. All these problems need to be further improved for accuracy and reducing of time.
Algorithms ; Cone-Beam Computed Tomography ; Humans ; Image Interpretation, Computer-Assisted ; Imaging, Three-Dimensional ; Software

Objective: To apply level set motion-based elastic registration method to radiotherapy CT image, then to provide technical support for the accurate evaluation of tumor and changing process of patients with endanger organ and its accumulative dose. Methods: Based on Vemuri’s level set motion method, we wrote the algorithm program using Matlab software and applied on two sets of 3D CT images from patients with cervical cancer and NPC for fully automatic elastic registration. Results: Comparing CT images before and after registration, for the cervical cancer patient, the minimum mean square error (MSE) decreased by 55.1%and correlation coefficient (CC) increased by 5.3%. For the NPC patient, MSE decreased by 32.1%and CC increased by 4.6%. Conclusion: From the image difference and evaluation parameters, the efficacy of level set motion-based elastic registration method was preliminarily demonstrated. In order to apply this method to clinical radiotherapy, dit needs to find a more accurate mathematical algorithm further in order to compute human anatomy deformation through image motion.

Objective To explore a new method of comparing the references images first to enhance the precision of the central point of the radiation treatment planning(RTP), try to establish a reference standard for this method in the nasopharyngeal cancer(NPC)and carcinoma of utercin cervix in the work of position verification. Methods For 50 RTPs of NPC and 20 RTPs of carcinoma of utercin cervix, the reference-CT-images in set-up and in position verification were compared, and to measure the difference between the two images. Then, in the same way, compare and measure the difference in the central-pointimages. Results For NPC, there was over 90% RTPs in which every difference measured was less than 2 mm;for carcinoma of utercin cervix, over 80% RTPs meet the criterion:the value of △MU1 ' or △MU2' was less than 5 mm and the others are less than 3 mm. Conclusions By comparing the references-CT-images in set-up and in position verification, the precision of the central point of the RTP is enhanced. The marks on the skin become more credible. So, it is feasible to perform the criterions in the work of position verification:for NPC every difference measured is less than 2 mm;for carcinoma of utercin cervix the value of △MU1 ' or △MU2 ' is less than 5 mm and the others are less than 3 mm.

ObjectiveTo investigate the anatomical changes and dose variation of rectum during radiotherapy in patients with cervical cancer.Methods Ten patients with cervical cancer underwent intensity-modulated radiotherapy using online cone beam computed tomography (CBCT) before each fraction.Rectum was contoured on each CBCT and projected onto the planning CT to analyze the changes of the rectal volume and position.The rectal volume receiving ≥ 45 Gy ( V45 ) was evaluated accordingly.Results227 CBCT images in 10 patients were collected.The rectal volume changed from ( 35.0 ± 7.3)cm3 to (97.7±14.7) cm3.The shift of rectal center was (0.14 ±0.06) cm in left and right direction,(0.24±0.10) cm in anterior and posterior direction,and (0.55±0.28) cm in superior and inferior direction.The V45 of rectum varied from (9.19±2.46)％ to (60.54 ±11.67)％.In7 of the 10 patients,rectal volume and V45 of the rectum had significant positive correlation (r =0.582 - 0.743,all P ＜ 0.01 ).Among the 227 images,the V45 of rectum was ≤50％ in 68 images (30.0％ ).ConclusionsSignificant changes in rectal volume and position occurred during fractionated radiotherapy in patients with cervical cancer,which resuhs in variations in the dose rectum received.For most patients,rectal volume and the V45of rectum had significant positive correlation.

Objective To investigate bladder anatomical changes and dose variation in patients with cervical cancer.Methods We analyzed 20 patients,undergoing external beam radiotherapy scanning cone beam CT(CBCT)before each fraction.Bladder was contoured on each CBCT,was projected onto the planning CT and assesses anatomical changes and dose variation.Results A total 451 CBCT images,for 20 patients were collected for analysis,show more change in bladder volume and position.In 15 cases bladder volume and V45 had no significant correlation(r=0.225 -0.473,all P>0.05),4 cases shows negative correlation(r=-0.564,P<0.05;r=-0.597,P<0.01;r=-0.942,P<0.01;r=-0.816,P<0.01),1 case shows positive correlation(r=0.662,P<0.01).Have more than the criteria(V45≤50%)number is 64/451(14.2%)in whole treatment.Conclusions For most patients by filling adequacy bladder,bladder dose variation is acceptable:CTV lager for individual patients should be closely observed its regression,implementation of the offline or online calibration.

Objective To explore the relationship between the overlap volume of organ at risk (OAR) and target (Voverlap) and the mean dose to OAR (DmOAR) in intensity-modulated radiotherapy (IMRT).Methods Fifty randomly selected patients undergoing IMRT for nasopharyngeal carcinoma (NPC) and an equal number of patients undergoing radical IMRT for cervical cancer in our hospital were enrolled as subjects.The relationship between Voverlap and DmoAR in IMRT was analyzed.The Matlab software was used to generate function to fit the relationship between Voverlap and DmOAR for different OARs.Results The Voverlap varied among patients with NPC or cervical cancer.The ratio of Voverlap to the volume of OAR (VOAR) was positively correlated with the ratio of DmOAR to the prescribed dose (Dp) (all P=0.01).A function was generated to fit the correlation between Voverlap/VOAR ratio and DmOAR/Dp ratio.Conclusions In IMRT,patients have different Voverlap/VoAR ratios due to varicd target volume,disease stages,OAR filling status,and OAR volume.As criteria for plan verification,a specific DmOAR value for each OAR should be calculated before radiotherapy planning based on the corresponding correlation function and the Voverlap/VoAR ratio with a fixed dose prescription.It can be used to reduce the subjective influence on the optimization of radiotherapy planning.

Objective To study the iso-center point coincidence of two accelerators with treatment planning system (TPS) based on γ passing rates of intensity-modulated radiotherapy (IMRT) plan verification.Methods Twenty-one IMRT plans were verified by Varian accelerator and twenty by Elekta accelerator with a gamma criterion of 3 mm/3％.The passing rates were measured when the iso-center point of TPS had-2,-1,0,1,and 2 mm shift in the x or y direction.A binomial curve of γwas fit to figure out the values of the two accelerators on the x and y axes when γ value reached the maximum.The γ pass rate difference was analysed by x2 test.Results The mean values of γ-2,γ-1,γ0,γ1,and γ2 in the x direction were (92.56±3.27) ％,(96.53± 1.82) ％,(96.13± 1.41) ％,(90.14± 2.87) ％,and (82.28± 4.69) ％ for Varian accelerator,and (94.82± 2.04) ％,(97.05± 2.02) ％,(98.38± 1.33) ％,(97.96± 1.44) ％,and (94.49±2.34)％ for Elekta accelerator.There was no significant difference in the mean value of γ0between the two accelerators (P=0.332).When γvalue reached the maximum,the values on the x and y axes were0.65 and-0.30 mm for Varian accelerator and 0.01 and 0.30 mm for Elekta accelerator,respectively.Conclusions In the same TPS,different accelerators have different degrees of coincidence of the actual field center point with the iso-center point of TPS,to which more attention should be paid in clinical practice.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is an effective method for treating multiple malignant hematological diseases and hereditary diseases.However,systematic internal organs disorders,especially pulmonary complications,are commonly following allo-HSCT,How to correctly diagnose and treat the coexistence of pulmonary infectious complications and pulmonary noninfectious complications has great importance.OBJECTIVE: To report a case suffered from pulmonary Aspergillus infection coexisted with obliterative bronchiolitis at 1 year following allo-HSCT,and to discuss the prevention,clinical manifestation and treating method by reviewing related literature.METHODS: At 373 days after allo-HSCT,the patient developed fever,dry cough,shortness of breath and dyspnea on exertion A high-resolution computed tomography of chest demonstrated that there were alveolar infiltrating in the upper,middle and lower lobe of the right lung,and the focus of infection was performed further biopsy.RESULTS AND CONCLUSION: The histopathological examination of the sample showed alveolus dilatation,epithelial cells hyperplasia,fibrinous obliteration in alveolar space and peribronchiolar lymphocytes inflammation,which were CD3(+),CD45RO(+),CD20(-),CD79a(-),MPO(-),CD34(-).Aspergillus fumigatus could be seen in the cultured biopsied tissue specimen.Pulmonary function test showed that,air flow obstruction with reduction of forced expiratory volume in one second was 59.27%.The patient was diagnosed as invasive pulmonary Aspergillus infection combined with bronchiolitis obliterans and was treated by caspofungin combined with intravenous voriconazole for invasive aspergillosis,methylprednisolone,azathioprine,intravenous immunoglobulin and azithromycin for bronchiolitis obliterans.At 40 days after treatment,the CT examination showed the focus was absorbed completely.

BACKGROUND:To date, there are few domestic reports about the influence of bone marrow mesenchymal stem cel s on T cel s proliferation in patients with aplastic anemia. And no study addresses the topic that if bone marrow mesenchymal stem cel s achieve immune regulation in aplastic anemia patients through inhibiting T cel s proliferation.
OBJECTIVE:To explore the effects of human bone marrow mesenchymal stem cel s on T cel s immune regulation in patients with aplastic anemia.
METHODS:Human bone marrow mesenchymal stem cel s were isolated, cultured and subcultivated in vitro. The morphological appearance of bone marrow mesenchymal stem cel s was observed and surface markers were measured by flow cyometry. The bone marrow mesenchymal stem cel s were co-cultured with T cel s extracted from peripheral blood of healthy volunteers and aplastic anemia patients for 7 days. The expressions of interferon-γ, interleukin-4 and interleukin-10 in the supernatants were detected with enzyme linked immunosorbent assay.
RESULTS AND CONCLUSION:The levels of interleukin-2 and interferon-γin the supernatant of aplastic anemia patients were significantly higher (P<0.05), while levels of interleukin-4 and interleukin-10 were significantly lower than that in healthy controls (P<0.05). Bone marrow mesenchymal stem cel s suppressed the elevated levels of interleukin-2 and interferon-γ, and enhanced the decreased levels of interleukin-4 and interleukin-10, thus regulating the immune dysfunction of aplastic anemia patients.

Objective To explore the dose of template-assisted ¹⁹²Ir source hypofractionated stereotactic brachytherapy (SABT) for peripheral lung cancer. Methods We retrospectively analyzed the dose parameters of GTV and OARs of 28 peripheral lung cancer patients treated with template-assisted ¹⁹²Ir-source hypofractionated SABT, and compared the dose parameters between SABT with virtual SBRT. Results The D_mean and V₁₅₀ for the GTV in the SABT plan were significantly higher than those in the SBRT plan (all P < 0.01). For OARs, all dosimetric parameters in the SABT plan were significantly lower than those in the SBRT plan (all P < 0.01), except for the D_1000cm³ and D_1500cm³ for the lung (P > 0.05). Conclusion Template-assisted ¹⁹²Ir source hypofractionated SABT ensures high dose in the gross tumor volume and reduces the dose in organs at risk in the treatment of peripheral lung cancer.