background: most preclinical studies are carried out on mice. for internal dose  assessment of a mouse, specific absorbed fraction (saf) values play an important role.  in most studies, saf values are estimated using older standard human organ compositions  and values for limited source target pairs. objective: saf values for monoenergetic photons of energies 15, 50, 100, 500,  1000 and 4000 ke...

We present our entry for the Longitudinal Multiple Sclerosis Challenge 2015 using 3D convolutional neural networks (CNN). We model a voxel-wise classifier using multi-channel 3D patches of MRI volumes as input. For each ground truth, a CNN is trained and the final segmentation is obtained by combining the probability outputs of these CNNs. Efficient training is achieved by using sub-sampling me...

Researchers in bioelectromagnetics often require realistic tissue, cellular and sub-cellular geometry models for their simulations. However, biological shapes are often extremely irregular, while conventional geometrical modeling tools on the market cannot meet the demand for fast and efficient construction of irregular geometries. We have designed a free, user-friendly tool in MATLAB that comb...

We introduce a system that automatically segments and classifies features in 3-D images. The system’s accuracy is comparable to manual segmentation. It takes 12 minutes to segment and classify 144 brain structures in 256x256x124 voxel image, while similar work by human took 8 months. The process starts with an atlas, a hand segmented and classified MRI of a normal brain. Given a subject’s data,...

Voxel-based morphometry from conventional T1-weighted images has proved effective to quantify Alzheimer's disease (AD) related brain atrophy and to enable fairly accurate automated classification of AD patients, mild cognitive impaired patients (MCI) and elderly controls. Little is known, however, about the classification power of volume-based morphometry, where features of interest consist of ...

By employing the triple coincidence between the γ trajectory intersections from β decaying isotopes emitting a third, prompt, photon ( γ-PET technique), sub-millimeter spatial resolution can be reached in 3 dimensions for the localization of a point source with a reduced requirement of reconstructed intersections per voxel compared to a conventional PET reconstruction analysis. Results of a Mon...

Purpose: To adapt a magnetization-prepared RF cycled spiral imaging technique, termed T1prep, for time-efficient RF-insensitive clinical prostate T1 quantification at 1.5 tesla, and evaluate SNR limits to voxel-based T1 mapping. Materials and Methods: A magnetization-prepared spiral imaging technique was adapted for robust T1 contrast development, multi-slice imaging within 5-minutes, and data ...

The Monte Carlo simulations using the mathematical phantom of a human body model is useful as a method of getting to know the details of the radiation exposure in a human body. However, it is very difficult to evaluate experimentally the validity of the calculation result of the simulation using the human body model. Then, the mathematical phantom of voxel-type (voxel phantom) for the Monte Car...

The Normal Distributions Transform (NDT) scan registration algorithm divides a point cloud using rectilinear voxel cells then models the points within each cell as a set of Gaussian distributions. A nonlinear optimization is performed in order to register the scans, however the voxel based approach results in a discontinuous cost function that hinders convergence. In this work, a segmented regi...

Purpose: Superimposition of two dimensional preoperative and postoperative facial images, including radiographs and photographs, are used to evaluate the surgical changes after orthognathic surgery. Recently, three dimensional (3D) imaging has been introduced allowing more accurate analysis of surgical changes. Surface based registration and voxel based registration are commonly used methods fo...