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Manavalakurichi, India

Shanthi G.,Womens Christian College | Thampi Thanka kumaran J.,NM Christian College | Allen Gnana raj G.,Scott Christian College | Maniyan C.G.,Health Physics Unit
Radiation Protection Dosimetry | Year: 2012

It is necessary to obtain the transfer factor (TF) of long-lived radionuclides because soil type and vegetation can affect TF. We studied the food crops commonly consumed by the general public of Kanyakumari district of south India. The main focus was on rice, fruits, vegetables and tapioca because the consumption of these is high. The soil to rice TF for the radionuclides, 226Ra, 232Th, 238U and 40 K are 8.8×10. -2, 14.2×10. -2, 5.8×10. -2 and 6.3×10. -2, respectively. The TF of tapioca for 226Ra, 232Th, 238U and 40 K are 6.2×10 -2, 11×10 -2, 1.9×10 -2 and 8.9×10 -2, respectively. For fruits and vegetables, the TFs are low. In the majority of the crops the non-edible parts accumulate more radionuclides than the edible parts. © The Author 2011. Published by Oxford University Press. All rights reserved. Source

Shanthi G.,Womens Christian College | Thampi Thanka Kumaran J.,NM Christian College | Allen Gnana Raj G.,Scott Christian College | Maniyan C.G.,Health Physics Unit
Radiation Protection Dosimetry | Year: 2010

The concentration of natural radionuclides (. 226Ra, . 232Th and . 40K) in the soil samples were determined for 28 locations in Kanyakumari district of southwest India by means of gamma spectroscopy with NaI (Tl) detector. The mean activity concentrations for . 232Th and . 40K are greater than the world average values reported by United Nations Scientific Committee on Effects of Atomic Radiation for areas of normal background radiation. Radiological indices were estimated for the radiation of the natural radioactivity of all soil samples. Estimated mean total absorbed dose in air from activity concentration of . 226Ra, . 232Th and . 40K in high background radiation areas (HBRAs) is 200 ± 30 nGy h. -1 and in low background radiation areas (LBRAs) is 29 ± 14 nGy h. -1. Annual outdoor effective dose was also calculated for HBRA and LBRA. Also the representative level index, which resulted from the natural radionuclides in the soil samples were also estimated and given. © The Author 2010. Published by Oxford University Press. All rights reserved. Source

Shanthi G.,Womens Christian College | Kumaran J.T.T.,NM Christian College | Raj G.A.G.,Scott Christian College | Maniyan C.G.,Health Physics Unit
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

The study was carried out to evaluate the radioactivity concentration in the food crops grown in high-level natural radioactive area (HLNRA) in south west India. Food samples collected were analysed by means of a gamma spectroscopy and estimated annual dietary intakes of the radioisotopes 226Ra, 228Ra, 228Th and 40K. The annual intake of the food stuffs was estimated on the basis of their average annual consumption. Calculations were also made to determine the effective dose to an individual consuming such diets. The intakes of these radionuclides were calculated using the concentrations in south Indian foods and daily consumption rates of these foods. Daily intakes of these radionuclides were as follows: 226Ra, 0.001-1.87; 228Ra, 0.0023-1.26, 228Th, 0.01-14.09 40K, 0.46-49.39Bq/day. The daily internal dose resulting from ingestion of radionuclides in food was 4.92 μSv/day and the annual dose was 1.79 mSv/yr. The radionuclides with highest consumption is 40K. © 2009 Elsevier B.V. All rights reserved. Source

Colagrande S.,University of Florence | Mazzoni L.N.,Health Physics Unit | Mazzoni E.,University of Florence | Pradella S.,University of Florence
Journal of Magnetic Resonance Imaging | Year: 2013

Purpose To prospectively evaluate the effect of gadoxetic acid (Gd-EOB-DTPA; Primovist, Bayer-Schering, Berlin, Germany) on quantitative diffusion-weighted imaging (DWI) using the Le Bihan IntraVoxel Incoherent Motion model and considering separately the following parameters: slow diffusion coefficient (D), fast diffusion coefficient (D*), perfusion fraction (PF), and apparent diffusion coefficient (ADC). Materials and Methods Twenty-four consecutive patients were submitted to the same magnetic resonance (MR)-DWI acquisition before and after gadoxetic acid administration. Patients were divided into four groups according to the time at which the DW sequence was repeated, then 5, 10, 15, 20 minutes after contrast agent administration. A total of 48 manually drawn regions of interest (ROIs) of about 1200 pixels were placed in the middle right liver lobe. The mean and standard deviation (SD) were calculated in each group/patient for every DWI-related parameter. Analysis of variance was performed (threshold P = 0.05). Bonferroni and Games-Howell post-hoc tests were applied if significant differences were found among groups; otherwise, data were averaged together. Results D, D*, PF, and ADC did not show any significant difference before and after contrast agent administration, at any time. Conclusion It is possible to perform DW acquisitions after gadoxetic acid administration without any significant variation of the values of DW-related parameters under consideration in this study. © 2013 Wiley Periodicals, Inc. Copyright © 2013 Wiley Periodicals, Inc. Source

Regini F.,University of Florence | Colagrande S.,University of Florence | Mazzoni L.N.,Health Physics Unit | Busoni S.,Health Physics Unit | And 4 more authors.
Journal of Computer Assisted Tomography | Year: 2015

Objectives To prospectively verify, in vivo, Le Bihan's model of signal decay in magnetic resonance/diffusion-weighted imaging (intravoxel incoherent motion) in healthy liver parenchyma. Methods Informed consent and institutional board approval were obtained. To measure both underfasting and postprandial conditions, apparent, slow, and fast diffusion (D∗) coefficients and perfusion fraction of liver parenchyma, 40 healthy volunteers (19 women and 21 men) underwent a 3.0-T magnetic resonance imaging examination, including portal venous flow measurements by a 2-dimensional phase-contrast sequence, and multi-b diffusion-weighted imaging acquired before and 30 minutes after a 600-Kcal meal. Parameters were measured by fitting procedure with regions of interest drawn on the right liver lobe. Paired-sample t test was performed to search for any statistically significant difference between preprandial and postprandial values of each parameter and of portal flow. Pearson correlation coefficients were calculated to evaluate the relationship between portal flow increase and diffusion-weighted imaging parameter changes in postprandial conditions. Interobserver agreement for measurement of the intravoxel incoherent motion parameters was determined, both for preprandial and postprandial values. Results Mean increase in postprandial portal flow was 98% (P < 0.0009). The t test did not show any statistically significant difference between the preprandial and postprandial values for apparent, slow diffusion coefficients and perfusion fraction (P ≥ 0.05), whereas a statistically significant postprandial increase (P < 0.01) of D∗ was detected. Correlation with portal venous flow increase at Pearson test was statistically significant for D∗ (P = 0.04) and nonsignificant for the other parameters. All the parameters showed wide variability, with a higher percent coefficient of variation for D∗. Interobserver agreement was always greater than 0.70. Conclusions This study verifies Le Bihan's theory, confirming that in the liver, D∗ is influenced by perfusional changes related to portal venous flow. © 2015 Wolters Kluwer Health, Inc. Source

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