Integrity of personal radiation protective equipment (PRPE): a 3-year longitudinal follow-up study

Background Personal radiation protective equipment (PRPE) such as lead aprons, vests, skirts and thyroid shields minimize radiation exposure of operators using ionizing radiation. However, PRPE might be prone to cracks and tears in the attenuating layer of the garments which results in inadequate radiation protection and increased operator dose. Currently, there are no uniform guidelines regarding regular inspection and/or rejection criteria of PRPE. Purpose This study aims to investigate the prevalence, qualification and quantification of PRPE integrity during a longitudinal follow-up. Methods All PRPE of a large, general hospital was yearly evaluated in the period 2018–2020. The equipment was inspected on a tele-operated X-ray table and cracks and tears were qualified and quantified using an X-ray opaque ruler. Rejection criteria of Lambert & McKeon were applied to accept or reject further use of the PRPE. In brief, all pieces, except for thyroid shields, with a total defect area larger than 670mm2 are rejected. For tears, specifically at the position of the gonads, an extra rejection criterion of 15mm2 is defined. For thyroid shields, the rejection criterion is set to 11mm2. Results In the 3-year follow-up period, a total of 915 PRPE were evaluated. 43.3% of PRPE showed tears and 29.3% needed to be rejected based on the Lambert & McKeon criteria. More specifically, in 2018, 2019 and 2020, respectively, 17.4%, 16.9% and 21.2% were rejected. In the attached figure, typical examples of visualized defects are represented. The median tear area (interquartile range) was 12 (30) mm2. Remarkably, of 195 newly registered PRPE, 8.7% showed tears in the first year of use of which 88.2% needed to be rejected. In the latter case, the median tear area (interquartile range) was 40 (50) mm2. Information regarding purchase date and size is missing in respectively 45.5% and 50.7% of the cases. Additionally, 13.7% lacked information regarding lead equivalency. Conclusion PRPE are prone to tears and cracks. Up to 40% of PRPE showed tears and cracks resulting in nearly 20% rejections. Newly purchased PRPE are not guaranteed to remain free of cracks and tears in the first year of use. These results urge the importance for regular X-ray based integrity analysis of PRPE. FUNDunding Acknowledgement Type of funding sources: None.

A New Birnbaum–Saunders Distribution and Its Mathematical Features Applied to Bimodal Real-World Data from Environment and Medicine

In this paper, we propose and derive a Birnbaum–Saunders distribution to model bimodal data. This new distribution is obtained using the product of the standard Birnbaum–Saunders distribution and a polynomial function of the fourth degree. We study the mathematical and statistical properties of the bimodal Birnbaum–Saunders distribution, including probabilistic features and moments. Inference on its parameters is conducted using the estimation methods of moments and maximum likelihood. Based on the acceptance–rejection criterion, an algorithm is proposed to generate values of a random variable that follows the new bimodal Birnbaum–Saunders distribution. We carry out a simulation study using the Monte Carlo method to assess the statistical performance of the parameter estimators. Illustrations with real-world data sets from environmental and medical sciences are provided to show applications that can be of potential use in real problems.

Construction of Knowledge Questionnaire Regarding Junk Food Consumption

Aim: The present paper aims to discuss on the construction and validation of a survey tool for measuring knowledge of people of West Bengal regarding junk foods. Method: Questionnaire was selected as the data collection tool. The questionnaire was prepared on the basis of certain dimensions and initially it had 41 items. At first, the questionnaire was administered to a target population of 30 respondents. After the pre-test among 30 respondents the readability, discrimination indices, and difficulty indices were determined for ‘Knowledge’ questionnaire. Rejection criteria were set for each parameter and the final questionnaire was constructed with the items retained after validation. The reliability of the tool was confirmed by Test-Retest method. Result: Finally, the knowledge questionnaire retained 31 items. Reliability co-efficient was found to be 0.76090 which was significant. Conclusion: Validity and reliability of the knowledge questionnaire were well established. There were 31 items in the final questionnaire depending on the rejection criterion. The high reliability of the questionnaire was found. This questionnaire will help to find out the level of knowledge of people regarding junk food and its effects on health. Key words: Junk food, Food consumption, Knowledge.

Intraoperative monitoring of olfactory function: a feasibility study

OBJECTIVEIntraoperative neuromonitoring of the chemical senses (smell and taste) has never been performed. The objective of this study was to determine if olfactory-evoked potentials could be obtained intraoperatively under general anesthesia.METHODSA standard olfactometer was used in the surgical theater with hydrogen sulfide (4 ppm, 200 msec). Olfactory-evoked potentials were recorded in 8 patients who underwent neurosurgery for resection of cerebral lesions. These patients underwent routine target-controlled propofol and sufentanil general anesthesia. Frontal, temporal, and parietal scalp subdermal electrodes were recorded ipsilaterally and contralaterally at the site of the surgery. Evoked potentials were computed if at least 70 epochs (0.5–100 Hz) satisfying the artifact rejection criterion (threshold 45 μV) could be extracted from signals of electrodes.RESULTSContributive recordings were obtained for 5 of 8 patients (3 patients had fewer than 70 epochs with an amplitude < 45 μV). Olfactory-evoked potentials showed N1 responses (mean 442.8 ± 40.0 msec), most readily observed in the patient who underwent midline anterior fossa neurosurgery. No component of later latencies could be recorded consistently.CONCLUSIONSThe study confirms that olfactory-evoked potentials can be measured in response to olfactory stimuli under general anesthesia. This demonstrates the feasibility of recording olfactory function intraoperatively and opens the potential for neuromonitoring of olfactory function during neurosurgery.

Structural-Acoustic Topology Analysis Based on Evolutionary Structural Optimization

Application of the evolutionary structural optimization (ESO) approach for structural acoustic optimization is investigated. Combining the sizing optimization, a more appropriate rejection criterion for ESO was put forward. There is a trial of applying modified evolutionary structural optimization (MESO) method in dynamic response problem. Finally, the topology optimization of plate structure under harmonic loading as example, the MESO approach is conducted. The numerical results show that the MESO is feasible in topology optimization analysis; and it expands the application of traditional ESO theory.