1.
Antioxidants Taken Orally prior to Diagnostic Radiation Exposure Can Prevent DNA Injury.
Velauthapillai, N, Barfett, J, Jaffer, H, Mikulis, D, Murphy, K
Journal of vascular and interventional radiology : JVIR. 2017;(3):406-411
Abstract
PURPOSE To evaluate efficacy of oral antioxidant treatment given to patients before radiologic procedures in reducing x-ray-induced DNA damage. MATERIALS AND METHODS In a single-center prospective controlled trial, antioxidant treatment with 2 g ascorbate, 1.2 g N-acetylcysteine, 600 mg lipoic acid, and 30 mg beta carotene was given to 5 consecutive participants before undergoing clinically indicated technetium-99m methylene diphosphonate (99mTc MDP) bone scans for cancer staging. These participants were compared with 5 participants without antioxidant treatment. DNA damage was visualized in peripheral blood mononuclear cells (PBMCs) before and after bone scans using three-dimensional microscopy and fluorescently labeled gamma-H2AX protein. Wilcoxon rank sum test was used to determine whether there was a statistically significant difference in the radiation received between the control and antioxidant groups, the number of foci/cell before and after bone scan within groups, and foci/cell after bone scan between groups. RESULTS There was a significantly higher number of gamma-H2AX foci/cell after ionization radiation in the control group compared with the antioxidant group (P = .009). There was no statistically significant difference in number of gamma-H2AX foci/cell before or after exposure in the antioxidant group; the number of gamma-H2AX foci/cell was statistically significantly higher (P = .009) in the control group after exposure to 99mTc MDP. CONCLUSIONS In patients undergoing 99mTc MDP bone scans, treatment with oral antioxidants before scanning significantly prevented DNA damage in PBMCs. Antioxidants may provide an effective means to protect patients and health care professionals from radiation-induced DNA damage during imaging studies.
2.
Monte Carlo-based inverse model for calculating tissue optical properties. Part II: Application to breast cancer diagnosis.
Palmer, GM, Zhu, C, Breslin, TM, Xu, F, Gilchrist, KW, Ramanujam, N
Applied optics. 2006;(5):1072-8
Abstract
The Monte Carlo-based inverse model of diffuse reflectance described in part I of this pair of companion papers was applied to the diffuse reflectance spectra of a set of 17 malignant and 24 normal-benign ex vivo human breast tissue samples. This model allows extraction of physically meaningful tissue parameters, which include the concentration of absorbers and the size and density of scatterers present in tissue. It was assumed that intrinsic absorption could be attributed to oxygenated and deoxygenated hemoglobin and beta-carotene, that scattering could be modeled by spheres of a uniform size distribution, and that the refractive indices of the spheres and the surrounding medium are known. The tissue diffuse reflectance spectra were evaluated over a wavelength range of 400-600 nm. The extracted parameters that showed the statistically most significant differences between malignant and nonmalignant breast tissues were hemoglobin saturation and the mean reduced scattering coefficient. Malignant tissues showed decreased hemoglobin saturation and an increased mean reduced scattering coefficient compared with nonmalignant tissues. A support vector machine classification algorithm was then used to classify a sample as malignant or nonmalignant based on these two extracted parameters and produced a cross-validated sensitivity and specificity of 82% and 92%, respectively.