The paper presents an equivalent ellipsoid approach for interpretation and visualization of extended current distributions in biomagnetic inverse problems. The example of simulations performed with physical thorax phantom is also given.

UNLABELLED We report the extended application of an automated computer technique for three-dimensional spatial registration of SPECT and PET studies. METHODS The technique iteratively reslices a misaligned data set until the sum of the absolute differences (SAD) from a reference data set is minimized. The registration accuracy was assessed in Hoffman brain phantom studies collected with known...

Introduction: The determination of accurate dose distribution is an issue of fundamental importance in radiotherapy, especially with regard to the fact that the human body is a heterogeneous medium. Therefore, the present study aimed to analyze the density and isodose depth profiles of 6 MV beam in a SP34 slab-wooden dust (pine)-SP34 slab (SWS) heterogeneous phantom.  Materials and Methods: Th...

PURPOSE In 2008, a national intensity modulated radiation therapy (IMRT) dosimetry intercomparison was carried out for all 23 radiation oncology institutions in Switzerland. It was the aim to check the treatment chain focused on the planning, dose calculation, and irradiation process. METHODS A thorax phantom with inhomogeneities was used, in which thermoluminescence dosimeter (TLD) and ioniz...

We present an experimental validation of a kilovoltage (kV) X-ray source characterization model in an anthropomorphic phantom to estimate patient-specific absorbed dose from kV cone-beam computed tomography (CBCT) imaging procedures and compare these doses to nominal weighted CT-dose index (CTDIw) dose estimates. We simulated the default Varian on-board imager 1.4 (OBI) default CBCT imaging pro...

background: prediction of the absorbed dose in irradiated volume plays an important role in the outcome of radiotherapy. application of small fields for radiotherapy of thorax makes the dose calculation process inaccurate due to the existence of electronic disequilibrium and intrinsic deficiencies in dose calculation algorithms. to study the lung absorbed dose in radiotherapy with small fields,...

BACKGROUND Patient-specific dose verification for treatment planning in helical tomotherapy is routinely performed using a homogeneous virtual water cylindrical phantom of 30 cm diameter and 18 cm length (Cheese phantom). Because of this small length, treatment with total marrow irradiation (TMI) requires multiple deliveries of the dose verification procedures to cover a wide range of the targe...

Background: Prediction of the absorbed dose in irradiated volume plays an important role in the outcome of radiotherapy. Application of small fields for radiotherapy of thorax makes the dose calculation process inaccurate due to the existence of electronic disequilibrium and intrinsic deficiencies in dose calculation algorithms. To study the lung absorbed dose in radiotherapy with smal...

Studying the complex thorax breathing motion is an important research topic for medical (e.g. fusion of function and anatomy, radiotherapy planning) and engineering (reduction of motion artifacts) questions. In this paper we present first results on investigating the 4D motion of segmented lung surfaces from CT scans at several different breathing states. For this registration task we extend th...