Ionizing radiation protection and the linear No-threshold controversy: Extent of support or counter to the prevailing paradigm.

This study has developed a relationship that categorized radiation protection and allows for a proper, clear, and concise review of the different classifications in terms of principles of protection, dose criteria, categories, fundamental tools, exposure situations, applications and control measures. With the groundwork laid, advances of the linear no-threshold (LNT) model which has attracted attention in the field of radiobiology and epidemiology were examined in detail. Various plausible dose-response relationship scenarios were x-rayed under low-dose extrapolation. Intensive review of factors opposing the LNT model involving radiophobia (including misdiagnosis, alternative surgery/imaging, suppression of ionizing radiation (IR) research); radiobiology (including DNA damage repair, apoptosis/necrosis, senescence protection) and cost issues (including-high operating cost of LNT, incorrect prioritization, exaggeration of LNT impact, risk-to-benefit analysis) were performed. On the other hand, factors supporting the use of LNT were equally examined, they include regulatory bodies' endorsement, insufficient statistical significance, partial DNA repair, variability of irradiated bodies, different latency periods for cancer, dynamic nature of threshold and conflicting interests. After considering the gaps in the scientific investigations that either support or counter the scientific paradigm on the use of LNT model, further research and advocacy is recommended that will ultimately lead to the acceptance of an alternative paradigm by the international regulators.

Sonographic Measurement of Liver Length And Percentiles Among Children in Warri, Nigeria.

PURPOSE: To use sonography to measure liver longitudinal length and determine liver longitudinal length percentiles among children in Warri, Delta State, Nigeria. METHODS: Midclavicular liver longitudinal length was measured in a sample of 320 children 10 years and younger. Mean liver longitudinal length was calculated for boys and girls separately, boys and girls combined, and each age group. The liver longitudinal length was correlated with age, height, weight, body surface area (BSA), and body mass index (BMI). The 10th, 25th, 50th, 75th and 95th percentiles were calculated. RESULTS: The mean liver longitudinal length for the boys and girls combined was 9.1 ± 0.6 cm. The relationship between liver longitudinal length and age, height, and weight was linear (r = 0.896, 0.906 and 0.910, respectively). A negative correlation was observed between liver longitudinal length and BMI (r = -0.424), but the relationship between liver longitudinal length and BSA was positive (r = 0.929). The 10th, 25th, 50th, 75th and 95th percentiles of the liver measurements conformed to the typical growth pattern of the liver. DISCUSSION: Although an increase in liver size was in line with expected somatic growth in infants and children 10 years and younger, increases in liver length was progressive and most rapid in the first year of life in the cohort of children in this study. In children 10 years and younger, sexual dimorphism in liver size appears to be of doubtful clinical significance because it tends to be transient. CONCLUSION: When age or any other anthropometric parameter is known, the presented typical values of liver longitudinal length, percentiles, and regression equations can serve as reference values during sonographic assessment of liver size among children in Warri, Nigeria. Furthermore, the use of different growth curves and different reference values during sonographic evaluation of the liver among children might be unnecessary.