Investigation of the Appropriate Threshold for Warning Dosage and Development of a Predictive Logistic Regression Model to Detect Dose- Error of Prednisolone Tablets / 医薬品情報学

Objective: The wrong dose of high-risk drugs such as oral steroids is a serious issue that needs to be addressed. This study aims to determine the appropriate upper tolerable dose threshold and to develop a multi-variable logistic regression model to detect dose-errors in oral prednisolone tablets.Methods: Data on Prednisolone prescriptions were obtained from a single center. Out of the data collected, positive cases consisted of cases where dose-related modifications were made. A univariate logistic regression model was developed with the current daily dose. In the model, the Youden Index was used to determine the upper tolerable dose threshold. The investigation was done to determine whether the performance of the multivariate model was improved by adding clinical department and previous prescription information as variables.Results: Univariate models (AUC: 0.645) with only current daily doses and estimated optimal thresholds of 6 mg/day or 11 mg/day, respectively were determined to be appropriate. Including variables improved the performance of the predictive model; the best performing model (AUC: 0.840) was derived when the following variables were entered: “current daily dose,” “current prescription days,” “clinical department,” “daily dose of the previous prescription,” and “prescription days of the previous prescription”.Conclusion: A single upper tolerance limit is insufficient to determine dose adequacy for prednisolone tablets owing to their broad clinical dose range. Itmay be possible to develop a high-performance dose audit support model by adding information.

Angular dependence of the optically stimulated luminescent dosimeter / 中国辐射卫生

0bjective To study the angular dependence of optically stimulated luminescent dosimeter (OSLD) with solid phantoms under SSDL radiation level 60Co radiation field, and to discuss the possibility of OSLD in volumetric modulated arc therapy (VMAT) and other rotating irradiation dose audit. Methods OSLDs were embedded in the two phantoms with the same size and material, respectively. The phantom 1 was set to make the first OSLD perpendicular to the beam, and the phantom 2 was set to make the second OSLD parallel to the beam. The OSLDs were irradiated at 8 angles: 0°, 45°, 90°, 135°, 180°, −45°, −90, −135°. The counts of the OSLSs were read and the response of each angle which normalized to 0° were calculated. Results When the OSLDs are perpendicular to the beam, the angular response is between −6.76% ～ +1.5%, with the maximum angular dependence at 90° and −90°. When the OSLDs are parallel to the beam, the angular response is between −1.74%～+1.67%, below 2%. Conclusion It is better to correct the sensitivity of dosimeters by Element Correction Factors (ECF) for dose audit. Under the condition of rotating irradiation, OSLD shoud be set parallel to the beam, which can better reduce the influence of angular dependence and facilitate further application research of VMAT dose audit.