On the relation between outdoor 222Rn and atmospheric stability determined by a modified Turner method

Publication date: September 2018
Source:Journal of Environmental Radioactivity, Volume 189
Author(s): Martin Bulko, Karol Holý, Monika Müllerová
In practice, information about atmospheric stability is often obtained from discrete stability classes determined from routine meteorological observations. However, changing concentrations of the radioactive gas ²²²Rn present in the atmosphere are also considered a good indicator of vertical dispersion and atmospheric stability. A complex, in-depth analysis between these different approaches of atmospheric stability assessment has not been performed so far, and was the main motivation behind this study. The study presents atmospheric radon data measured in Bratislava (Slovakia) and stability indexes (SI) calculated according to a modified Turner method during a period of one year. Basic features of the diurnal and seasonal variations of these variables are discussed. It was found that the time series of radon activity concentration (RAC) lags approximately 5 h behind that of the Turner stability classes adjusted for temperate climate regions. Various time lags were also identified between RAC and meteorological variables used to determine the stability classes. Evaluation of seasonal trends revealed a low variability of mean monthly values of stability classes compared to the variability of mean monthly values of RAC. Another notable difference between RAC and stability indexes was found – while the stability index can both increase and decrease with wind speed, concentration of outdoor radon was never observed to increase with increasing wind speed. In spite of the mentioned discrepancies, the time series of RAC and SI are generally in a good agreement. This is especially true if one compares the deviations of RAC and SI from their mean daily values, when the differences in their seasonal variability are eliminated. Deviations of RAC can be used to calculate diurnal variations of stability indexes. Analysis of a complete year of data also revealed a roughly linear relationship between average values of RAC and calculated stability indexes, because in large datasets random processes tend to cancel each other out.



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Multiparametric Whole-body MRI with Diffusion-weighted Imaging and ADC Mapping for the Identification of Visceral and Osseous Metastases From Solid Tumors

Publication date: Available online 4 April 2018
Source:Academic Radiology
Author(s): Michael A. Jacobs, Katarzyna J. Macura, Atif Zaheer, Emmanuel S. Antonarakis, Vered Stearns, Antonio C. Wolff, Thorsten Feiweier, Ihab R. Kamel, Richard L. Wahl, Li Pan
Rationale and ObjectivesThe purpose of this study was to investigate the use of multiparametric, whole-body, diffusion-weighted imaging (WB-DWI) and apparent diffusion coefficient (ADC) maps with T2-weighted magnetic resonance imaging (MRI) at 3T for the detection and monitoring of metastatic disease in patients.Materials and MethodsFifty-four participants (32 healthy subjects and 22 patients) were scanned with WB-DWI methods using a 3T MRI scanner. Axial, sagittal, or coronal fat-suppressed T2-weighted (T2WI), T1-weighted (T1WI), and DWI images were acquired. Total MRI acquisition and set-up time was approximately 45 minutes. Metastatic disease on MRI was confirmed based on T2WI characteristics. The number of lesions was established on computed tomography (CT) or positron emission tomography (PET-CT). Whole-body ADC maps and T2WI were constructed, and region-of-interests were drawn in normal and abnormal-appearing tissue for quantitative analysis. Statistical analysis was performed using a paired t tests and P < .05 was considered statistically significant.ResultsThere were 91 metastatic lesions detected from the CT or PET-CT with a missed recurrent lesion in the prostate. Multiparametric WB-MRI had excellent sensitivity (96%) for detection of metastatic lesions compared to CT. ADC map values and the ADC ratio in metastatic bone lesions were significantly increased (P < .05) compared to normal bone. In soft tissue, ADC map values and ratios in metastatic lesions were decreased compared to normal soft tissue.ConclusionWe have demonstrated that multiparametric WB-MRI is feasible for oncologic staging to identify bony and visceral metastasis in breast, prostate, pancreatic, and colorectal cancers. WB-MRI can be tailored to fit the patient, such that an "individualized patient sequence" can be developed for a comprehensive evaluation for staging and response during treatment.



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Ultrasound for diagnosing radiographically occult scaphoid fracture

Abstract

Objective

To systematically review the literature on the performance of ultrasound in diagnosing radiographically occult scaphoid fracture.

Methods

A systematic search was performed in the MEDLINE and Embase databases. Original studies investigating the performance of ultrasound in diagnosing radiographically occult scaphoid fracture in more than 10 patients were eligible for inclusion. Studies that included both radiographically apparent and occult scaphoid fractures (at initial radiography) were only included if independent data on radiographically occult fractures were reported. Methodological quality of the studies included was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. Accuracy data were extracted. Sensitivity and specificity were pooled with a bivariate random-effects model.

Results

The inclusion criteria were met by 7 studies; total sample size comprised 314 patients. All studies, except 1, included cortical disruption of the scaphoid in their diagnostic criteria. The sensitivity and specificity of ultrasound in diagnosing radiographically occult scaphoid fracture ranged from 77.8% to 100% and from 71.4% to 100% respectively, with pooled estimates of 85.6% (95% CI: 73.9%, 92.6%) and 83.3% % (95% CI: 72.0%, 90.6%) respectively. Exclusion of two studies with a high risk of bias in any QUADAS-2 domain did not affect the pooled results.

Conclusion

Ultrasound can diagnose radiographically occult scaphoid fracture with a fairly high degree of accuracy. Because of its relatively low costs and fairly high sensitivity, ultrasound seems more cost-effective than empiric cast immobilization and may be used when CT and MRI are not readily available.

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Fatigue, insomnia and hot flashes after definitive radiochemotherapy and image-guided adaptive brachytherapy for locally advanced cervical cancer: An analysis from the EMBRACE study

To evaluate the pattern of manifestation of fatigue, insomnia and hot flashes within the prospective, observational, multi-center EMBRACE study.

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Clinical features and presentation of oral potentially malignant disorders

Publication date: Available online 4 April 2018
Source:Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Author(s): Saman Warnakulasuriya
Oral potentially malignant disorders (OPMDs) are conditions that precede the appearance of invasive cancers of the oral cavity. The term embraces both precancerous lesions and conditions referred to in the earlier WHO definitions. Leukoplakia is the most common OPMD; erythroplakia though rare is more serious. Several variants of leukoplakia are recognized and clinical subtyping could help in predicting the prognosis to a limited extent. Biopsy is essential to confirm the provisional clinical diagnosis and timely referral to a specialist is indicated. Certain OPMDs such as oral submucous fibrosis are encountered particularly in population groups from Asia with specific life-style habits. This review provides clinical descriptions of the wide range of PMDs encountered in the oral cavity as a prelude to the topics discussed in this focus issue.



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Molecular markers associated with development and progression of potentially premalignant oral epithelial lesions: current knowledge and future implications

Publication date: Available online 4 April 2018
Source:Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology
Author(s): Nikolaos G. Nikitakis, Monica Pentenero, Maria Georgaki, Catherine F. Poh, Douglas E. Peterson, Paul Edwards, Mark Lingen, John J. Sauk
Identification and management of potentially premalignant oral epithelial lesions (PPOELs) at highest risk of malignant transformation (MT) holds great promise for successful secondary prevention of oral squamous cell carcinoma (OSCC), potentially reducing oral cancer morbidity and mortality. However, to date, neither clinical nor histopathologic validated risk predictors have been identified that can reliably predict which PPOELs will definitively progress to malignancy. In addition, the management of PPOELs remains a major challenge. Arguably, progress in the prevention and treatment of oral premalignancy and cancer will require improved understanding of the underlying molecular mechanisms, facilitating the discovery of diagnostic, prognostic and predictive markers, as well as the identification of novel targeted therapeutics.This review provides a synopsis of the molecular biomarkers that have been studied in PPOELs and have been correlated with the presence and grade of dysplasia and/or their propensity to undergo MT to OSCC. The emphasis is on highlighting new emerging research fields, particularly epigenetic events, including methylation and miRNA regulation. Several promising biomarkers are highlighted. Current limitations and challenges are discussed. Recommendations for future focused research areas, in order to validate and promote clinically useful applications, are offered.



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Diffusion-Weighted Imaging With Apparent Diffusion Coefficient Mapping for Breast Cancer Detection as a Stand-Alone Parameter: Comparison With Dynamic Contrast-Enhanced and Multiparametric Magnetic Resonance Imaging

Purpose The aims of this study were to compare dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) with diffusion-weighted imaging (DWI) with apparent diffusion coefficient mapping as a stand-alone parameter without any other supportive sequence for breast cancer detection and to assess its combination as multiparametric MRI (mpMRI) of the breast. Materials and Methods In this institutional review board–approved single-center study, prospectively acquired data of 106 patients who underwent breast MRI from 12/2010 to 09/2014 for an imaging abnormality (Breast Imaging Reporting and Data System 0, 4/5) were retrospectively analyzed. Four readers independently assessed DWI and DCE as well as combined as mpMRI. Breast Imaging Reporting and Data System categories, lesion size, and mean apparent diffusion coefficient values were recorded. Histopathology was used as the gold standard. Appropriate statistical tests were used to compare diagnostic values. Results There were 69 malignant and 41 benign tumors in 106 patients. Four patients presented with bilateral lesions. Dynamic contrast-enhanced MRI was the most sensitive test for breast cancer detection, with an average sensitivity of 100%. Diffusion-weighted imaging alone was less sensitive (82%; P

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