scholarly journals Impact of Eye and Breast Shielding on Organ Doses During Cervical Spine Radiography: Design and Validation of MIRD Computational Phantom

2021 ◽  
Vol 9 ◽  
Author(s):  
Wiam Elshami ◽  
Huseyin Ozan Tekin ◽  
Shams A. M. Issa ◽  
Mohamed M. Abuzaid ◽  
Hesham M. H. Zakaly ◽  
...  
Keyword(s):  
Dose Reduction ◽  
Absorbed Dose ◽  
Relative Difference ◽  
Phantom Study ◽  
Tissue Cell ◽  
Anthropomorphic Phantom ◽  
Organ Doses ◽  
Target Organs ◽  
Cervical Spine Radiography ◽  
The Impact

Purpose: The study aimed to design and validate computational phantoms (MIRD) using the MCNPX code to assess the impact of shielding on organ doses.Method: To validate the optimized phantom, the obtained results were compared with experimental results. The validation of the optimized MIRD phantom was provided by using the results of a previous anthropomorphic phantom study. MIRD phantom was designed by considering the parameters used in the anthropomorphic phantom study. A test simulation was performed to compare the dose reduction percentages (%) between the experimental anthropomorphic phantom study and the MCNPX-MIRD phantom. The simulation was performed twice, with and without shielding materials, using the same number and locations of the detector.Results: The absorbed dose amounts were directly extracted from the required organ and tissue cell parts of output files. Dose reduction percentages between the simulation with shielding and simulation without shielding were compared. The highest dose reduction was noted in the thymus (95%) and breasts (88%). The obtained dose reduction percentages between the anthropomorphic phantom study and the MCNPX-MIRD phantom were highly consistent and correlated values with experimental anthropomorphic data. Both methods showed Relative Difference (%) ranges between 0.88 and 2.22. Moreover, the MCNPX-MIRD optimized phantom provides detailed dose analysis for target and non-target organs and can be used to assess the efficiency of shielding in radiological examination.Conclusion: Shielding breasts and eyes during cervical radiography reduced the radiation dose to many organs. The decision to not shield patients should be based on research evidence as this approach does not apply to all cases.

A PHANTOM STUDY SHOWING THE IMPORTANCE OF BREAST SHIELDING DURING HEAD CT

2020 ◽  
Vol 188 (4) ◽  
pp. 464-469 ◽  
Author(s):  
Nika Zalokar ◽  
Nejc Mekiš
Keyword(s):  
Computed Tomography ◽  
Dose Reduction ◽  
Phantom Study ◽  
Anthropomorphic Phantom ◽  
Head Ct ◽  
Lead Shield ◽  
Phantom Measurements ◽  
Lead Shielding ◽  
Head Computed Tomography

Abstract This study aimed to investigate the dose to the breasts during head computed tomography (CT) if lead shielding is used. The study was performed in two major hospitals using helical and axial protocols on an anthropomorphic phantom. Measurements were performed with and without the use of a lead shield of 0.5 mm equivalent density. The results showed a significant decrease in dose with the lead shielding in both hospitals. During the helical protocol, the use of shielding significantly reduced the dose by 96% in Hospital A and 82% in Hospital B. The dose reduction during axial protocol was also significant: 95% in Hospital A and 86% in Hospital B with lead shielding. Considering the significant dose reduction of 82% up to 96% during this study, we highly recommend the shielding of breasts regardless of the protocol used during head CT examinations.

scholarly journals Evaluation of Factors Affecting Absorbed Dose, Optimization Methods and Patient Dose Reduction in Dental Cone Beam CT (CBCT)

2020 ◽  
Author(s):  
Azam Asgari ◽  
Ali Asghar Parach ◽  
Zahra Nekoofar ◽  
Elahe Daneshian
Keyword(s):  
Image Quality ◽  
Dose Reduction ◽  
Absorbed Dose ◽  
Field Size ◽  
Ct Scans ◽  
Cone Beam ◽  
Organ Doses ◽  
Factors Affecting ◽  
Dental Ct ◽  
Scan Time

Introduction: Nowadays the use of cone beam computed tomography in dental imaging is increasing, although this method has a much lower dose than conventional CT scans, it delivers a higher dose than the panoramic and periapical patients therefore, , the aim of this study was to investigate the factors affecting the patients' dose in dental CBCTs and methods of optimizing and reducing the patients' dose. Various factors such as the use of thyroid collar, lead goggles, field size, device type, imaging parameters such as tube voltage and current, alternating or pulsed radiation; type, amount and shape of the filter, 360 degree or partial rotation of tube and scan time, can affect the absorbed dose of the patient in dental CT scans. Among these, the use of thyroid collar (42% reduction), lead goggles (6% reduction),the smallest possible field of view ( up to 90%), pulse irradiation, patient sitting position and 180o rotation angle instead of 360o (more than 50% reduction) cause significant reduction in the organ doses and effective dose of the patients. It should also be kept in mind that measures taken to reduce the patients' dose should not impair image quality and, depending on the patient's condition, the radiographer will select the dose reduction parameters without degrading the image quality.

scholarly journals A Monte Carlo Determination of Dose and Range Uncertainties for Preclinical Studies with a Proton Beam

Cancers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1889
Author(s):  
Arthur Bongrand ◽  
Charbel Koumeir ◽  
Daphnée Villoing ◽  
Arnaud Guertin ◽  
Ferid Haddad ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Proton Beam ◽  
Dose Response ◽  
Small Animal ◽  
Absorbed Dose ◽  
Normal Tissue Damage ◽  
Dose Homogeneity ◽  
And Control ◽  
The Impact

Proton therapy (PRT) is an irradiation technique that aims at limiting normal tissue damage while maintaining the tumor response. To study its specificities, the ARRONAX cyclotron is currently developing a preclinical structure compatible with biological experiments. A prerequisite is to identify and control uncertainties on the ARRONAX beamline, which can lead to significant biases in the observed biological results and dose–response relationships, as for any facility. This paper summarizes and quantifies the impact of uncertainty on proton range, absorbed dose, and dose homogeneity in a preclinical context of cell or small animal irradiation on the Bragg curve, using Monte Carlo simulations. All possible sources of uncertainty were investigated and discussed independently. Those with a significant impact were identified, and protocols were established to reduce their consequences. Overall, the uncertainties evaluated were similar to those from clinical practice and are considered compatible with the performance of radiobiological experiments, as well as the study of dose–response relationships on this proton beam. Another conclusion of this study is that Monte Carlo simulations can be used to help build preclinical lines in other setups.

scholarly journals Improved adherence with Medicines Use Review service in Slovenia: a randomized controlled trial

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Urška Nabergoj Makovec ◽  
Igor Locatelli ◽  
Mitja Kos
Keyword(s):  
Medication Adherence ◽  
Controlled Trial ◽  
Test Group ◽  
Multiple Linear Regression Model ◽  
Relative Difference ◽  
Control Group ◽  
Adherence Support ◽  
Medicines Use ◽  
The Impact ◽  
Medicines Use Review

Abstract Background Based on several existing patient-oriented activities, Medicines Use Review (MUR) service was standardized and officially adopted in Slovenia in 2015. Service aims to provide adherence support and ensure safe and effective medicines use. Therefore, the aim of the study was to evaluate the benefits of MUR in Slovenia, primarily the impact on medication adherence. Methods A randomised controlled trial was performed in community pharmacies to compare MUR with standard care. Patients were randomised into either the test (patients received MUR by a certified MUR provider at visit 1), or control group. The study primary outcome was self-reported adherence to multiple medications, assessed by electronic ©Morisky Widget MMAS-8 Software at the first visit (V1) and after 12 weeks (V2). A sub-analysis of intentional and unintentional non-adherence was performed. MUR impact was defined as the relative difference in ©MMAS-8 score after 12 weeks between the test and control group. A multiple linear regression model was used to predict MUR impact based on baseline adherence (low versus medium and high). Several secondary outcomes (e.g. evaluation of drug-related problems (DRPs)) were also assessed. Results Data from 153 (V1) and 140 (V2) patients were analysed. Baseline adherence was low, moderate and high in 17.6, 48.4 and 34.0% patients, respectively. In the low adherence subpopulation, test group patients showed a 1.20 point (95% CI = 0.16–2.25) increase in total ©MMAS-8 score (p = 0.025) compared to control group patients. A 0.84 point (95% CI = 0.05–1.63) increase was due to intentional non-adherence (p = 0.038), and a 0.36 point (95% CI = − 0.23-0.95) was due to unintentional non-adherence (p = 0.226). Additionally, statistically significant decrease in the proportion of patients with manifested DRPs (p < 0.001) and concerns regarding chronic medicines use (p = 0.029) were revealed. Conclusion MUR service in Slovenia improves low medication adherence and is effective in addressing DRPs and concerns regarding chronic medicines use. Trial registration ClinicalTrials.gov - NCT04417400; 4th June 2020; retrospectively registered.

scholarly journals Prevalence of internalizing disorders, symptoms, and traits across age using advanced nonlinear models

2021 ◽  
pp. 1-10
Author(s):  
Hanna M. van Loo ◽  
Lian Beijers ◽  
Martijn Wieling ◽  
Trynke R. de Jong ◽  
Robert A. Schoevers ◽  
...  
Keyword(s):  
Internalizing Symptoms ◽  
Nonlinear Models ◽  
Generalized Additive Models ◽  
Population Sample ◽  
Internalizing Disorders ◽  
Relative Difference ◽  
Additive Models ◽  
Point Prevalence ◽  
Cross Sectional ◽  
The Impact

Abstract Background Most epidemiological studies show a decrease of internalizing disorders at older ages, but it is unclear how the prevalence exactly changes with age, and whether there are different patterns for internalizing symptoms and traits, and for men and women. This study investigates the impact of age and sex on the point prevalence across different mood and anxiety disorders, internalizing symptoms, and neuroticism. Methods We used cross-sectional data on 146 315 subjects, aged 18–80 years, from the Lifelines Cohort Study, a Dutch general population sample. Between 2012 and 2016, five current internalizing disorders – major depression, dysthymia, generalized anxiety disorder, social phobia, and panic disorder – were assessed according to DSM-IV criteria. Depressive symptoms, anxiety symptoms, neuroticism, and negative affect (NA) were also measured. Generalized additive models were used to identify nonlinear patterns across age, and to investigate sex differences. Results The point prevalence of internalizing disorders generally increased between the ages of 18 and 30 years, stabilized between 30 and 50, and decreased after age 50. The patterns of internalizing symptoms and traits were different. NA and neuroticism gradually decreased after age 18. Women reported more internalizing disorders than men, but the relative difference remained stable across age (relative risk ~1.7). Conclusions The point prevalence of internalizing disorders was typically highest between age 30 and 50, but there were differences between the disorders, which could indicate differences in etiology. The relative gap between the sexes remained similar across age, suggesting that changes in sex hormones around the menopause do not significantly influence women's risk of internalizing disorders.

Lonsurf (trifluridine/tipiracil): Assessing the impact of dose related toxicities and progression free survival in (refractory) metastatic colorectal cancer

2021 ◽  
pp. 107815522110179
Author(s):  
Olivia R Court
Keyword(s):  
Colorectal Cancer ◽  
Metastatic Colorectal Cancer ◽  
Dose Reduction ◽  
Progression Free Survival ◽  
Electronic Patient Records ◽  
Free Survival ◽  
Length Of Treatment ◽  
Common Grade ◽  
Grade 3 ◽  
The Impact

In the RECOURSE trial which lead to its accreditation, Lonsurf (trifluridine/tipiracil) was shown to extend progression free survival (PFS) by 1.8 months in metastatic colorectal cancer. This Trust audit aims to assess the average quantity of cycles of Lonsurf received by participants and the length of time it extends PFS. Similarly, to identify how many participants required a dose-reduction or experienced toxicities which necessitated supportive therapies. Quantitative data was collected retrospectively from all participants who had received ≥1 cycle of Lonsurf from The Clatterbridge Cancer Centre (CCC) from 2016 until June 2020. Participant electronic patient records were accessed to identify toxicity grading, length of treatment received, the date progression was identified, if dose reductions were applied and if supportive therapies were administered. Lonsurf extends PFS in patients with metastatic colorectal cancer at CCC by 3.0 months (95% CI: 2.73–3.27) and average treatment length was 2.4 months. However, 78 participants (41.5%) received a dose reduction due to toxicities. A total of 955 toxicities were recorded by participants; the most commonly reported toxicities irrespective of grade were fatigue (33.8%), diarrhoea (13.8%) and nausea (12.3%). The most common grade ≥3 toxicities were constipation and infection. The most frequently utilised supportive therapies were loperamide (49.6%) and domperidone (49.1%). Granulocyte colony stimulating factor (GCSF) was required by patients on 5 occasions (0.3%) in total. Lonsurf extends median PFS in patients with metastatic colorectal cancer by 3.0 months. The most common grade ≥3 toxicities which necessitated supportive therapies or a dose reduction were gastrointestinal and infection.

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