ABSTRACT
Objective:To comprehensively evaluate the performance of the iterative cone beam CT (iCBCT) imaging mode of Varian linear accelerators and to explore its specific advantages in clinical application.Methods:The kV cone beam CT (CBCT) imaging systems of Halcyon 2.0, Edge, and VitalBeam linear accelerators from Tianjin Medical University Cancer Institute & Hospital were selected, among which Halcyon 2.0 and Edge were equipped with the iCBCT imaging mode. The Penta-Guide phantom was used to evaluate the registration accuracy of iCBCT imaging modes. The accuracy of treatment couch position was measured by a ruler. The image quality of the iCBCT and conventional CBCT modes of various imaging devices were analyzed using the CatPhan604 phantom. The imaging beam-on time and reconstruction time were measured to assess image acquisition efficiency. The uniformity, spatial resolution, contrast, contrast-to-noise ratio (CNR), image acquisition time and reconstruction time between two imaging modes were statistically analyzed by t-test. Results:The maximum deviations of image registration measurement results of the iCBCT mode for Halcyon 2.0 and Edge accelerators compared to the standard values were 0.7 mm and 0.6 mm, respectively. The treatment couch position error of all devices was less than 1 mm. The iCBCT images under head scanning protocol primarily improved the uniformity and CNR. Compared to conventional CBCT images, Halcyon iCBCT increased the uniformity and CNR by 2.50% ( P<0.001) and 78.85% ( P<0.001), respectively, while Edge increased them by 2.18% ( P<0.001) and 86.42% ( P<0.001), both superior to VitalBeam CBCT images. Under pelvis scanning protocols, iCBCT images primarily improved the CNR compared to conventional CBCT images. Halcyon and Edge iCBCT increased the CNR by 113.57% ( P<0.001) and 133.87% ( P<0.001), respectively, both superior to VitalBeam CBCT images. In terms of image acquisition efficiency, the average reconstruction times for Halcyon and Edge iCBCT images increased by 7.28 s and 15.53 s, respectively, and the total image acquisition time of Halcyon accelerator was the shortest. Conclusions:While ensuring the registration accuracy, iCBCT imaging mode can significantly improve the CNR of images and improve the uniformity of images under head scanning protocol. The Halcyon imaging system can enhance image acquisition efficiency.
ABSTRACT
This study is to explore characteristic indexes in evaluation criteria for rat skin anaphylactoid test comparing skin blue spot OD values at the treated position and the control position in the same animal. Common contrast agents, traditional Chinese medicine injections and injections' active pharmaceutical ingredients or excipients in the existing clinical anaphylactoid reaction reports were taken as test drugs in the rat skin anaphylactoid test to define the K value: K > 2 represents positive anaphylactoid reaction, 1.2 ≤ K ≤ 2 represent doubtable anaphylactoid; K < 1.2 represents negative anaphylactoid reaction, which were taken as the criteria for evaluating anaphylactoid of tested drugs. The evaluation result and that for classic criteria were compared to study the applicability of K value. According to the comparison, K value, as the evaluation criteria in the rat skin anaphylactoid test, can more truly reflect the actual situation of skin aizen and minimize the error caused by animal individual factors. Compared with positive and negative two-level criteria for blue spot diameter, K value's positive, doubtable and negative three-level criteria are more objective and accurate. Therefore, K value can be used as the evaluation criteria in the rat skin anaphylactoid test.
Subject(s)
Animals , Female , Humans , Rats , Drug Hypersensitivity , Allergy and Immunology , Drugs, Chinese Herbal , Rats, Sprague-Dawley , Skin Tests , MethodsABSTRACT
PURPOSE: The aim of this study was to investigate the prognostic significance of the expression of p53 gene product in operable invasive breast cancer by performing immunohistochemical analysis. MATERIALS AND METHODS: Between January 1993 and December 2001, 440 operable invasive breast cancer patients underwent immunohistochemical staining for p53, and we retrospectively analyzed these results together with the clinical outcomes. RESULTS: The overexpression of p53 was detected in 51.6% of the cases. The overexpression of p53 was inversely correlated with lymph node metastasis (p=0.005). The tumor size, tumor histology, histologic grade, hormonal receptor status and tumor stage were not related to the overexpression of p53. Multivariate Cox regression analysis indicate that lymph node metastasis, tumor size and the p53 expression were the significant prognostic factors for overall survival; lymph node metastasis, the estrogen receptor status and the p53 expression were the significant prognostic factors for relapse free survival. On the subgroup analysis, the p53 non-expressors showed better 7-year overall survival (92.7% vs. 76.7%, respectively, p=0.011) and relapse free survival (74.9% vs. 57.8%, respectively, p=0.032) than did the p53 overexpressors for the patients with lymph node metastasis. However, for the patients without lymph node metastasis, the survival rates were not different for both the p53 non-expressors and the p53 overexpressors. CONCLUSION: Immunohistochemical staining of the p53 gene product was an independent prognostic factor for predicting survival of the lymph node positive invasive breast cancer patients.