With the rapid development of intensity modulated radiation therapy (IMRT) technique,the accuracy of radiotherapy has improved,while the pretreatment dose verification has become more complex.Although the experimental measurements,a widely used way to perform dose verification,is accurate and effective,its time-consuming and labor-intensive is still a challenge for physicist.The independent dose verification method such as the depth dose-off axis ratios (OAR) empirical model,Clarkson integral model,convolution model and Monte Carlo model,could partially solve these problems effectively when the accuracy is ensured within a certain range.This approach could save physicists' time to conduct dose recalculation and plan check,and has become the hotspot in the world.This paper,therefore,mainly introduces the correction-based and the model-based independent dose verification methods,and briefly discusses the development of dose verification for IMRT plans.

Objective To analyze the impact of electronic portal imagingdevice (EPID) position error on three-dimensional dose verification of volumetric modulated arc therapy (VMAT).Metbods Five Suremark SL-20 lead points were fixed on Elekta tray,and EPID images were collected in 0-360° rotation,one image per 5°.The position error relative to the accelerator was analyzed via Matlab.Then the images position error was corrected according to the analysis,and the 3D dose was reconstructed with the corrected images.The dose distributions of double arcs,clockwise arc(arc 1),and counterclockwise arc (arc 2) of 16 nasopharyngeal carcinoma patients' VMAT plan were evaluated by γ analysis,and the results of before and after position error correction were compared.Results Compared to 0° gantry angle,the error of source to the image distance (SID) was maximum (1.20 cm) when the gantry angle was 180°.On account of the SID change,the maximum error along the up-down (y) direction in the iso-center planar was 2.28 mm and the left-right (x) direction error was within ± O.5 mm.The 3D γ analyses of 16 nasopharyngeal carcinoma in VMAT plans were obviously increased after the position error along y was corrected.The double arcs,arc1 and arc 2 were increased by (4.12 ±1.67) ％ (t =-9.86,P＜ 0.05),(3.47±1.64) ％ (t=-8.46,P＜ 0.05) and (5.08±1.30) ％ (t=-15.63,P＜ 0.05) in 5％/3 mm standard,respectively.However,in 3％/3 mm standard,γ value of the double arcs,arc 1 and arc2 were increased by (7.63 ±2.24) ％ (t =-13.63,P＜ 0.05),(6.03 ±2.07) ％ (t =-11.66,P＜ 0.05),(9.17 ±2.23) ％ (t =-16.41,P＜ 0.05),respectively.Since the EPID position error along x was corrected after y,the 3D γ analysis of reconstruction dose indicated that the average of the 5％/3 mm and 3％/3 mm γ value were increased by 0.23％ and 0.24％,respectively.Conclusions EPID motion error along the gantry to table direction of the accelerator can't be ignored.When reconstruct dose based on EPID,a modification should be made for rebuilding more accurate patients' 3D dose distribution.

To investigate the impact of respiratory movement to determine the target volume on cone beam CT (CBCT) for lung tumor, we used CIRS dynamic thorax phantom (Model-CIRS008) to simulate the sinusoidal motion of lung tumor. With a constant amplitude, the ratio of the time of near-end-expiratory and near-end-inspiratory (E/I) changed when it was scanned with CBCT. We analyzed the contrast changes of target by extracting the CT value of each pixel on the center line of the target movement direction. The targets were contoured with region growing method and compared with the motion volume generated by the tumor trajectory method. The result showed that the contrast of near-end-expiratory increased and the contrast of near-end-inspiratory decreased with increasing E/I. The contoured volume generated by region growing method decreased with increasing E/I. When E/I = 4, the amplitude A = 1 cm, diameter of 1 cm and 3 cm target volumes were reduced by 48.2% and 22.7%. The study showed that CBCT was not suitable to be used to accurately determine the range of lung tumor movement. The internal target volume (ITV) may be underestimated in CBCT images.
Cone-Beam Computed Tomography ; Humans ; Lung Neoplasms ; diagnostic imaging ; Movement ; Phantoms, Imaging ; Respiration

Objective To evaluate the characteristics and clinical suitability of the ArcCHECK diode array for volumetric-modulated arc therapy (VMAT) verification.Methods The intrinsic sensitivity,short and long term reproducibility,dose and dose rate dependence,dose per pulsed dependence,field sizes dependence and directional response of the diodes were measured.The results of the diodes were compared with the measurement results of an ionization chamber and calculated results of treatment planning system.Gamma index was used to analyze the dose difference between the calculation and measurement for random selected 211 verified VMAT plans.Results The ArcCHECK performed well for all tests except directional dependence,which varies from a minimum of-3.9％ (seen only when the beam was incident on the diode at 180°) to a maximum of 7.7％ (approximately at 255°).Average gamma analysis passing rates with 3 mm/3％ for 113 nasopharyngeal cancer,48 cervical cancer and 50 rectal cancer patients VMAT plans were 93.5％,95.7％ and 97.5％,respectively,statistical significance has been found between either two of the groups (t=-12.69-4.88,all P＜ 0.01).Conclusions With proposed calibration method,the ArcCHECK diode array is very suitable for VMAT pretreatment verification,the complexity of VMAT plan is the main factor affecting the passing rate.

Objective:To improve the therapeutic gain ratio from 125I seed implants by investigating the QA/QC strategies used in brachytherapy treatment of lung cancer. Methods:A total of 287 lung cancer and pulmonary metastases cases were studied. Among which, 184 are male and 103 are female with a mean age of 61.9 years. The NOA-NSCLC subgroup and pulmonary metastases were targeted on conventional CT positioning. Considering that COA-NSCL subgroup on the tumor target area is difficult to determine with CT, the coincidence circuit SPECT was used to assist in positioning. A dose-volume histogram was constructed to evaluate the quality of the TPS and optimization. Corrections on real-time positioning are necessary when using an image-guided implantation. The C-LC should be aligned with the FFB for CT-guided percutaneous puncture implantation. After implantation, dosimetry verification was con-ducted. Results:The NOA-NSCLC subgroup, comprising the risk organs such as heart, lung, and spinal column, received an average dose of 137, which was significantly lower than that of normal tissue dose tolerance. The NOA-NSCLC subgroup and lung metastases have matched peripheral dosages of 92.1 and 106.2 Gy with local-control efficiency rates of 91.97% (126/137) and 96.0% (48/50), 1-year survival rates of 91.24%and 83.4%(42/50), and 2-year survival rates of 50.36%(69/137) and 52.3%(26/50), respectively. The 35 COA-NSCL subgroup and 65 lung cancer group have local control efficiency rates of 91.43%(32/35) and 92.3%(60/65) and 1-year survival rates of 88.57%(31/35) and 80.30%(53/66), respectively. Conclusion:Proper radiation dosimetry as a QA/QC strategy was found to improve particle-implantation therapy gain and greatly reduce the risks of radiation pneumonia and pulmonary fibrosis.

Objective To analyze safety,effectiveness and prognosis of thyroidectomy in elderly patients with thyroid carcinoma.Methods A retrospective analysis was conducted in 142 elderly patients undergoing thyroidectomy for thyroid carcinoma in our hospital from October 2010 to March 2012.Clinical data of surgical treatment and postoperative pathogenetic conditions,including the incidence rate of operation complications,the rate of local relapse and distant metastasis,were analyzed.And the influencing factors on prognosis were also analyzed.Results Thyroidectomies for thyroid carcinoma were successfully completed in all patients.There were a total of 13 cases with postoperative complications,yielding a total complication rate of 9.15 ％,including an incision infection in 6 patients,hoarseness in 1 patient,and hypocalcemia in 6 patients.During median follow-up of 51 months,there were 12 patients dead,16 patients relapsing,and 6 patients with local and distant metastasis.Univariate analysis showed that age,lymph node metastasis,and clinical stage may affect the prognosis of elderly patients with thyroid cancer.Multivariate Cox Logistical analysis indicated that age,lymph node metastasis,and clinical stage were independent factors associated with the prognosis of elderly patients with thyroid carcinoma.Conclusions Age,lymph node metastasis,and clinical stage are independent factors for prognosis of elderly patients with thyroid carcinoma.

This study aims to obtain two whole-genome sequences of enzootic nasal tumor virus of goats(ENTV-2)from Anhui Province and analyzed the genetic diversity of ENTV-2 gene.Nasal secretion samples and blood samples of six goats with enzootic nasal adenocarcinoma(ENA)were collected from a goat farm in Anhui Province.The total RNA was extracted by the TRIzol method.The DNA interference was removed by the two-step reverse transcription.The ENTV-2 was detec-ted by PCR.Then,two positive samples were selected and five pairs of primers were used to ampli-fy the whole-genome sequences of ENTV-2.After sequencing and splicing,two sequences were up-loaded to the database for comparative analysis with the sequences in the NCBI database.Finally,the genetic evolution tree was constructed.ENTV-2 was detected in the nasal secretion samples,but not in the blood of the six ENA goats.The ENTV-2 genes were approximately 7 400 bp in length,named ENTV-2AH1(DDBJ accession no.:LC762616)and ENTV-2AH2(DDBJ accession no.:LC762617),respectively.Two sequences showed 99.2％and 99.1％homology with the Fujian strain(ENTV-2FJ)and Guangxi strain(ENTV-2-DA0),respectively.They were in the same evo-lutionary branch.In this study,two whole-genome sequences of ENTV-2 were obtained in Anhui for the first time,which can help to further study the genetic diversity of ENTV-2 in China.

Objective To assess the feasibility of the log file-based three-dimensional independent dose verification system for the quality assurance of clinical radiotherapy.Methods The statistical values of the percentage depth dose,off-axis curves and output factor calculated by the Mobius system were statistically compared with the measured data by three-dimensional water tank.The three-dimensional independent dose verification in clinical radiotherapy plan and the acceleratr log file-based three-dimensional dose verification during the treatment were performed in 17 patients with nasopharyngeal cancer.The accuracy of dose calculation and reconstruction of Mobius system was assessed.A statistical analysis was performed on the intra-fractionalγpass rate (3％/3 mm) for each patient to evaluate the stability of intra-fractional radiotherapy.Results The percentage depth dose,off-axis curve and output factor statistically calculated by the Mobius system matched well with the data measured by three-dimensional water tank.The dose-volume histogram (DVH) parameters between the target area and organ at risk during clinical radiotherapy plan were statistically compared in 17 patients with nasopharyngeal cancer.The maximum deviation was-2.16％ for the three-dimensional independent dose verification in the clinical radiotherapy plan,and 0.18 Gy for the accelerator log file-based three-dimensional dose verification.The averageγpass rate for 17 nasopharyngeal cancer patients was 99.26％,and the maximum deviation of intra-fractional radiotherapy was below 0.5％.Conclusions The function of dose reconstruction and independent calculation of the Mobius system yeilds the same accuracy with the treatment planning system,which can quickly perform three-dimensional independent dose verification in the clinical radiotherapy plan and accelerator log file-based three-dimensional dose verification throughout the treatment,thereby guarantting and providing the safe and reliable technical support for clinical treatment.

BACKGROUND: Smad3 linker phosphorylation plays essential roles in tumor progression and metastasis. We have previously reported that the mutation of Smad3 linker phosphorylation sites (Smad3-Erk/Pro-directed kinase site mutant constructs [EPSM]) markedly reduced the tumor progression while increasing the lung metastasis in breast cancer. METHODS: We performed high-throughput RNA-Sequencing of the human prostate cancer cell lines infected with adenoviral Smad3-EPSM to identify the genes regulated by Smad3-EPSM. RESULTS: In this study, we identified genes which are differentially regulated in the presence of Smad3-EPSM. We first confirmed that Smad3-EPSM strongly enhanced a capability of cell motility and invasiveness as well as the expression of epithelial-mesenchymal transition marker genes, CDH2, SNAI1, and ZEB1 in response to TGF-β1 in human pancreatic and prostate cancer cell lines. We identified GADD45B, CTGF, and JUNB genes in the expression profiles associated with cell motility and invasiveness induced by the Smad3-EPSM. CONCLUSIONS: These results suggested that inhibition of Smad3 linker phosphorylation may enhance cell motility and invasiveness by inducing expression of GADD45B, CTGF, and JUNB genes in various cancers.
Breast Neoplasms ; Cell Line ; Cell Movement ; Epithelial-Mesenchymal Transition ; Humans ; Lung ; Neoplasm Metastasis ; Pancreatic Neoplasms ; Phosphorylation ; Phosphotransferases ; Prostatic Neoplasms ; Sequence Analysis, RNA

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