ABSTRACT
Objective:To test the relative response of a detector matrix used for measuring of the dose distribution in radiotherapy in order to ensure the accuracy and reliability of dose distribution measurement result.Methods:The two adjacent detectors can be irradiated at the same radiation dose by translating the detector matrix. The relative response of each detector to the reference detector can be obtained by combining the recursive algorithm. At the same time, the measurement data at different test steps are corrected to the reference step by setting the reference step, which correct the influence on the relative response result caused by the variation of the radiation condition and the detector response.Results:Based on the actual test of a 32 × 32 detector matrix, the relative response of each detector of the detected detector matrix to the reference detector varied from 0.896 to 1.077, with the expanded uncertainty of the relative response result being 0.8% ( k=2). Conclusions:On the premise of no known distribution of a radiation field, the relative response relationship of each detector of a detector matrix can be obtained by this method accurately and expediently, which provides a basic method for the performance evaluation of the detector matrix. The same idea can also be used to determine the relative response relationship of other detector matrices for different measurement purposes.
ABSTRACT
OBJECTIVE: To develop a method for the determination of levodopa in human plasma and study aarodopa's pharmacokinetics. METHODS: Experiments were performed on Waters 2010 HIPLC system with a 474 fluorecence detector (?EX = 278nm, ?Em = 325nm) and a Lichrospher 100 C18 column. The mobile phase(pH3. 7) was 90% water containing 0.08 mmol/L EDTA, 70mmol/L KH2PO4, 2. 08mmol/L sodium heptanesulfonate and 10% methanal. The flow rate was 1. 0ml/min. The plasma sample was directly injected for determination after being deproteinized with perchloric acid. RESULTS: The linear range was 0. 125-4.0ug/ml,the limitation of detection was 0. 25ug/ml,within- day RSD