Introduction Kilovoltage (kV) X‐ray beams are an essential modality in radiotherapy. Solid state detectors are widely available in radiotherapy departments, but their use for kV dosimetry has been limited to date. This study aimed to evaluate the dosimetric performance of a range of solid state detectors for kV dosimetry. Method Percentage depth doses (PDDs) and relative output factors (ROFs) were measured on an XStrahl 300 unit (XStrahl‐Ltd., UK) using 60, 100, 150, and 300 kVp X‐ray beams. The fields were defined by circular applicators with field sizes of 2, 5, 8, and 10 cm diameter and square applicators of field sizes 10 × 10 and 20 × 20 cm2. The following Physikalisch‐Technische Werkstätten (PTW) dosimeters were used for measurements: Advanced Markus, PinPoint 3D and Semiflex ionization chambers; photon, electron, and stereotactic radiosurgery (SRS) diodes plus the microDiamond detector. All PDDs were normalized at 5 mm depth, and ROFs were measured at 3 mm depth to avoid collisions with the end of the applicators. ROFs measured using chambers were corrected for polarity and ion‐recombination effects. Results and discussion PDD measurements for 60, 100, and 150 kVp beams exhibited good agreement between all diodes and the ionization chambers over the entire range of depths except in the first few millimeters near the surface. However, for the 300 kVp, all diode detectors exhibited an overresponding behavior compared to reference depth dose data measured with the Advanced Markus chamber. ROFs with the diodes were higher than the Advanced Markus chamber at low energy, and the magnitude of these differences is inversely proportional to the field sizes. The PTW P diode showed the highest variation of up to 15% in the output factor compared to the Advanced Markus chamber. Conclusion This study evaluated the dosimetric performance of a range of solid state detectors in kV relative dosimetry. This study showed that diode detectors are a suitable replacement for ionization chambers for the PDD measurement of low energy kV beams (60–150 kVp) except for the PDD of 60 kVp with the smaller field sizes. However, an overresponding behavior of diode detectors at 300 kVp beams shows that diode detectors are not suitable for the PDD measurement of high energy kV beams. Generally, all solid state detectors overresponded to ROF measurements, indicating that it is not suitable for ROF measurements. In general, both shielded and unshielded diodes produced a similar dosimetric response, which demonstrates that the energy dependence of solid state detectors should be considered before they are used for any kV relative dosimetric measurements.
With the clinical increase in Type 2 Diabetes worldwide, several interventions to decrease its incidence have been investigated. One such intervention is Vitamin D supplementation, as it affects Insulin secretion from the pancreas and Insulin receptors in the cells of the body. This systematic review addresses whether or not Vitamin D supplementation has a role in reducing the risk of developing Type 2 Diabetes. Systematic searches were conducted on PubMed, and Cochrane Library mainly but also checked Google Scholar. Randomized controlled trials, systematic trials and cohort studies were retrieved that included keywords pertaining to Vitamin D supplementation and the incidence of Type 2 Diabetes. Exclusion criteria included studies that looked at different forms of Diabetes, studies including patients aged less than 18 or more than 85 years of age and studies that were not English language. For all the trials identified, the incidence of Type 2 Diabetes among the cohort receiving vitamin D supplementation was compared to the cohort receiving placebo medication. Additionally, the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) was analyzed to observe if there was a difference between Insulin resistance among these two cohorts between the start of the trials and the end. Thirteen randomized controlled trials were identified. Seven of these identified incidences of Type 2 Diabetes as a research outcome, out of which six showed no statistically significant impact of vitamin D on the incidence of Type 2 Diabetes. Out of the 13 trials, 10 analyzed the impact of vitamin D supplementation on patients' HOMA-IR. In six of these trials, patients receiving vitamin D supplementation had a decrease in their HOMA-IR, while it increased in 4 trials. In seven of the ten trials that analyzed for HOMA-IR, the HOMA-IR was less in the vitamin D cohort than the placebo cohort. There is insufficient evidence to suggest that vitamin D supplementation significantly reduces the incidence of Type 2 Diabetes despite its effects on insulin resistance. Further research in this area would be helpful in order to influence clinical guidelines on vitamin D supplementation among patients at risk of Type 2 Diabetes.Categories: Endocrinology/Diabetes/Metabolism, Internal Medicine, Preventive Medicine Keywords: preventative medicine, colecalciferol and type 2 diabetes, vitamin d and diabetes, prevention of diabetes, duration of diabetes mellitus, risk of cardiovascular diseases, systematic review and meta analysis, vitamin-d deficiency, vitamin d level, diabetes mellitus type 2
Myocarditis is one of the complications reported with COVID-19 vaccines, particularly both Pfizer-BioNTech and Moderna vaccines. Most of the published data about this association come from case reports and series. Integrating the geographical data, clinical manifestations, and outcomes is therefore important in patients with myocarditis to better understand the disease. A thorough literature search was conducted in Cochrane library, PubMed, ScienceDirect, and Google Scholar for published literature till 30 March 2022. We identified 26 patients eligible from 29 studies; the data were pooled from these qualifying case reports and case series. Around 94% of patients were male in this study, the median age for onset of myocarditis was 22 years and 85% developed symptoms after the second dose. The median time of admission for patients to hospitals post-vaccination was three days and chest pain was the most common presenting symptom in these patients. Most patients had elevated troponin on admission and about 90% of patients had cardiac magnetic resonance imaging (CMR) that showed late gadolinium enhancement. All patients admitted with myocarditis were discharged home after a median stay of four days. Results from this current analysis show that post-mRNA vaccination myocarditis is mainly seen in young males after the second dose of vaccination. The pathophysiology of vaccine-induced myocarditis is not entirely clear and late gadolinium enhancement is a common finding on CMR in these patients that may indicate myocardial fibrosis or necrosis. Prognosis remains good and all patients recovered from myocarditis, however further studies are advisable to assess long-term prognosis of myocarditis.
We present a case of a 62-year-old male who was admitted to the hospital with out-of-hospital ventricular fibrillation (VF) arrest. He had a VF arrest in 2011 and was admitted to another hospital. He had several investigations excluding cardiac magnetic resonance imaging, all of which were normal. He was playing tennis on both occasions when he experienced the VF arrest. His electrocardiogram on admission showed AF with partial right bundle branch block, inverted T waves in V1-V2, low voltage QRS complexes, ventricular ectopic in lead V1-V2, and prolonged QTc. His echocardiogram showed normal left ventricular function and a dilated right ventricle. Cardiac magnetic resonance imaging showed a dilated RV cavity size with impaired systolic function and dyskinetic region in the mid-ventricular free wall proximal to the insertion of the moderator band and late gadolinium enhancement in both right and left ventricles insertion points and mid-wall late gadolinium enhancement in the basal inferolateral wall suggestive of arrhythmogenic right ventricular cardiomyopathy. He had a single chamber VVI implantable cardioverter-defibrillator fitted for primary prevention and was discharged home. He had outpatient follow-up and showed good improvement and his implantable cardioverter-defibrillator checks were satisfactory and did not experience any shocks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.