Dependence of brain DTI maps of fractional anisotropy and mean diffusivity on the number of diffusion weighting directions.

The rotational variance dependence of diffusion tensor imaging (DTI) derived parameters on the number of diffusion weighting directions (N) has been investigated by several Monte Carlo simulation studies. However, the dependence of fractional anisotropy (FA) and mean diffusivity (MD) maps on N, in terms of accuracy and contrast between different anatomical structures, has not been assessed in detail. This experimental study further investigated in vivo the effect of the number of diffusion weighting directions on DTI maps of FA and MD.

Cancer risk from professional exposure in staff working in cardiac catheterization laboratory: insights from the National Research Council's Biological Effects of Ionizing Radiation VII Report.

Background: Occupational doses from fluoroscopy-guided interventional procedures are the highest ones registered among medical staff using x-rays. The aim of the present study was to evaluate the order of magnitude of cancer risk caused by professional radiation exposure in modern invasive cardiology practice.

Methods: From the dosimetric Tuscany Health Physics data bank of 2006, we selected dosimetric data of the 26 (7 women, 19 men; age 46 +/- 9 years) workers of the cardiovascular catheterization laboratory with effective dose >2 mSv.

Comparison between remnant and red-marrow absorbed dose in thyroid cancer patients submitted to 131I ablative therapy after rh-TSH stimulation versus hypothyroidism induced by L-thyroxine withdrawal.

Objective: In thyroidectomized patients, increased levels of thyroid stimulating hormone (TSH) are necessary to maximize I uptake. Traditionally, this has been achieved by withdrawing L-thyroxine (L-T4) for 4-6 weeks, inducing hypothyroidism in patients. The availability of a genetically engineered version of the recombinant human TSH (rh-TSH) provides an alternative tool to enhance the TSH serum level without inducing hypothyroidism.

[Sustainability of medical imaging in cardiology].

Every year, 5 billion imaging testing are performed worldwide, and about 1 out of 2 are cardiovascular examinations. According to recent estimates, 30 to 50% of all examinations are partially or totally inappropriate. This represents a potential damage for patient undergoing imaging (who takes the acute risks of a stress procedure and/or a contrast study without a commensurable benefit), an exorbitant cost for the society and an excessive delay in the waiting lists for other patients needing the examination.

A study of the possibility of curing Graves' disease based on the desired reduction of thyroid mass (volume) as a consequence of 131I therapy: a speculative paper.

Purpose: The possibility of predicting the final volume of Graves' disease thyroids submitted to 131I therapy could allow the physician to decide what activity to administer based on the desired volume reduction instead of on a fixed value of the thyroid radiation absorbed dose. In this paper the relationship between maximum uptake of 131I, fractional reduction of thyroid volume and outcome of Graves' disease is discussed.

Methods: The results are based on ultrasonography thyroid volume measurements before administration of therapy and at the moment of recovery from Graves' disease (thyroid stimulating hormone >0.

A predictive mathematical model for the calculation of the final mass of Graves' disease thyroids treated with 131I.

Substantial reductions in thyroid volume (up to 70-80%) after radioiodine therapy of Graves' hyperthyroidism are common and have been reported in the literature. A relationship between thyroid volume reduction and outcome of 131I therapy of Graves' disease has been reported by some authors. This important result could be used to decide individually the optimal radioiodine activity A0 (MBq) to administer to the patient, but a predictive model relating the change in gland volume to A0 is required.

A dosimetric approach to patient-specific radioiodine treatment of Graves' disease with incorporation of treatment-induced changes in thyroid mass.

The traditional algorithms (Marinelli-Quimby and MIRD) used for the absorbed dose calculation in radionuclide therapy generally assume that the mass of the target organs does not change with time. In radioiodine therapy for Graves' disease this approximation may not be valid. In this paper a mathematical model of thyroid mass reduction during the clearance phase (30-35 days) after 131I administration to patients with Graves' disease is presented.