No abstract

The ultrasound imaging has the potential to become a dominant technique for noninvasive therapies and least invasive surgeries. Few cases may require using multiple probes of different units with different modes of ultrasound on the same patient. It generates imaging artifacts, which makes it complicated to gather information from the acquired image. This study was to identify and analyse the artifacts which are produced by simultaneous use of two probes with different/same operating frequencies. Six imaging studies were performed. First of all, the imaging artifacts of the 3.5 MHz and 6 MHz center frequencies with similar (longitudinal) positions of the probes. Secondly, with similar operating frequencies the 6 MHz probe changed from longitudinal to transverse placement to analyse the resulting artifacts. The third study was done with transverse placement of 3.5 MHz probe. The rest of the three cases were just the repetition with common pulse frequencies. Such artifacts in 3D ultrasound images are more obscure than the other artifacts associated and reported.

No abstract

The cause of brain tumors remains unknown for the majority of patients. An association between radon and brain tumor incidence and mortality has been reported previously in Europe. Exposure to high particulate pollution may disrupt the blood brain barrier allowing intracranial exposure to radon. We investigated the association between exposure to residential radon and particulate pollution and incidence of brain tumors in the US. Materials/Methods: Summary county-level median radon testing results were obtained from AirChek and divided into quartiles. Counties with no radon testing results were excluded. Annual air quality index values were obtained from the EPA, averaged from 2000-2010, and divided into tertiles. Counties without air pollution values were excluded. These data were used to generate four groups of counties: high radon/high particulate, high radon/low particulate, low radon/high particulate, and low radon/low particulate. Using incidence data from the Central Brain Tumor Registry of the United States (CBTRUS) which covers 100% of the US from 2004-2016, age-adjusted incidence rates were generated overall and stratified by histology, sex, race/ethnicity, and age groups. Incidence rate ratios and associated p values were generated to test for significant differences in incidence. Results: A significant association was found with high exposure to radon, high particulate pollution (high/high exposure) compared to low exposure overall and for multiple specific histologies. Incidence rates of glioblastoma (w8%) (RR Z 0.91, p Z <0.001), meningioma (7-32% higher) (RR Z 0.89, <0.001), and nerve sheath tumor (9-31% higher) (RR Z 0.87, p Z <0.001) were significantly higher in the high/high exposure group as compared to all other groups. This pattern was consistent when stratified by race/ethnicity. For Blacks (13-31% higher) and Hispanics (10-23% higher) only, incidence of pituitary tumors was significantly higher in the high/high group. The highest rates of brain tumor incidence were noted in patients over the age of 40. Conclusion: We found a significant association between high exposure to both residential radon and particulate pollution and incidence of brain tumors overall, across multiple histologies and when stratified by race/ ethnicity. These data represent the first epidemiologic evidence associating radon and pollution exposure to brain tumor incidence and warrant further study.