Feasibility of fast, four-dimensional computed tomography-based O-ring LINAC plans for lung stereotactic body radiotherapy in patients with poor performance status.

Purpose: We aimed to retrospectively analyzed the feasibility of fast four-dimensional computed tomography (4DCT)-based O-ring LINAC treatment for patients with an average respiratory amplitude was< 0.5 cm and who cannot endure long treatment times due to poor performance status in lung 4D-stereotactic body radiotherapy (SBRT). Methods: This study included data of 38 patients who received lung 4D-SBRT and had average respiratory amplitude< 0.5 cm in the full phase. C-arm LINAC plans were based on 4DCT data obtained at phase values ranging from 20-70% using a C-arm LINAC. O-ring LINAC plans were retrospectively established based on 4DCT data obtained at phase values of 0-90% using an O-ring LINAC. The conformity index (CI), homogeneity index (HI), and gradient measurement of the planning target volumes (PTV) were analyzed to compare dosimetric data between C-arm LINAC and O-ring LINAC plans. Organs at risk were analyzed in accordance with the Radiation Therapy Oncology Group 0915 protocol. Treatment delivery time and total monitor units were analyzed to compare the efficiency of treatment delivery. Statistical comparisons were performed using the Wilcoxon signed-rank test (P< 0.05). Results: For the PTV, there was no significant difference in the CI or HI between C-arm LINAC and O-ring LINAC plans. For organs-at-risk, all plans met the criteria for dose constraint. There was a significant difference between C-arm LINAC and O-ring LINAC plans except in the spinal cord. Treatment delivery time was 92% longer for C-arm LINAC plans than for O-ring LINAC plans. The total MU value for C-arm LINAC plans was 9.6% higher than that for O-ring LINAC plans. Conclusion: We verified the feasibility of fast 4DCT-based O-ring LINAC treatment for patients with average respiratory amplitude< 0.5 cm and who cannot endure long treatment times due to poor performance status in lung 4D-SBRT.

Dosimetric comparison of VitalBeam® and HalcyonTM 2.0 for hypofractionated VMAT with simultaneous integrated boost treatment of early-stage left-sided breast cancer.

PURPOSE: This study compared the quality of treatment plans for early-stage, left-sided breast cancer, as planned for and delivered by the HalcyonTM and VitalBeam® . MATERIALS AND METHODS: Fifteen patients diagnosed with early-stage left-sided breast cancer, who had received VMAT with hypofractionated SIB, were recruited. All cases were planned using HalcyonTM comprising a dual-layer MLC (DL-MLC) and VitalBeam® with a Millennium 120 MLC (VB-MLC). For the PTVs, the quality of coverage (QC), conformity index (CI), and homogeneity index (HI) were calculated for each plan. The dosimetric differences between the two treatment plans were statistically compared using the Wilcoxon signed-rank test (p < 0.05). To evaluate delivery efficiency, the average delivery time for each patient's treatment plan was recorded and compared. RESULTS: For the PTVs, the two plans (DL-MLC and VB-MLC) were comparable in terms of the QC, CI, and HI. However, V30Gy and Dmean for the heart in the DL-MLC plan were significantly reduced by 0.49% and 14.6%, respectively, compared with those in the VB-MLC plan (p < 0.05). The Dmean value for the ipsilateral lung in the DL-MLC plan significantly decreased by 5.5%, compared with that in the VB-MLC plan (p < 0.05). In addition, the delivery times for the DL-MLC and VB-MLC plans were 79 ± 10 and 101 ± 11 s, respectively. CONCLUSIONS: DL-MLC plans were found to improve OAR sparing. In particular, when treating left-sided breast cancer via DL-MLC plans, the risk of heart toxicity is expected to be reduced.

A recombinant protein-based ELISA for detecting antibodies to foot-and-mouth disease virus serotype Asia 1.

A recombinant protein-based ELISA was evaluated for detecting antibodies to foot-and-mouth disease virus (FMDV) serotype Asia 1. The recombinant protein (rP13C) was derived from the P1 precursor and 3C protease genes that were cloned into a single expression vector and expressed in insect cells. This protein elicited a low titer of FMDV neutralizing antibodies in pigs. Its utility as a diagnostic antigen was explored in a blocking ELISA using monoclonal antibodies. The rP13C ELISA yielded higher endpoint titers than the liquid phase blocking (LPB) ELISA and virus neutralization test performed on sera from goats challenged with FMDV post-vaccination. The rP13C ELISA correctly scored the FMD international reference weak positive serum. The relative sensitivity between the rP13C ELISA and LPB ELISA was equivalent for vaccinated sera. With this comparable sensitivity, the rP13C ELISA exhibited a specificity of 99.7% for domestic naive swine, bovine and caprine sera. This report demonstrates that an ELISA using recombinant proteins has the potential to replace the LPB ELISA using an inactivated FMDV antigen as a simple and robust serological tool for screening antibodies to FMDV serotype Asia 1.

Effect of metC mutation on Salmonella Gallinarum virulence and invasiveness in 1-day-old White Leghorn chickens.

Salmonella enterica serotype Gallinarum (S. Gallinarum) is the causative agent of fowl typhoid (FT) in chickens. FT is a severe systemic disease of chickens causing heavy economic losses to the poultry industry through mortality, reduced egg production and culling of precious breeding stocks. In this study, a metC (encoding cystathionine beta lyase) mutant was produced from a virulent strain of S. Gallinarum by Mini-Tn5 insertional inactivation. The mutant was significantly attenuated in virulence for 1-day-old White Leghorn chickens. Inactivation of metC resulted in 10(4)-fold increase in the LD50 when compared with the wild type parent. The metC mutant showed an in vivo competitiveness defect in the challenged chickens and significantly lower (P < 0.01) bacterial burden in the reticuloendothelial organs when compared with the wild-type parent. These results indicate that metC gene is important for virulence of S. Gallinarum in chickens.