State-of-the-art radiotherapy treatment planning systems provide reliable estimates of the therapeutic radiation but are known to underestimate or neglect the stray radiation exposures. Most commonly, stray radiation exposures are reconstructed using empirical formulas or lookup tables. The purpose of this study was to develop the basic physics of a model capable of calculating the total absorb...

Introduction: Simultaneous fMRI and EEG is an attractive means by which to investigate non-invasively human brain function. The combination of the two techniques offers high spatial and temporal resolution. Furthermore, the two metrics derive from different physical mechanisms (electrical activity and haemodynamics) meaning that their combination may shed light on the process of neurovascular c...

The Delta4 biplanar diode array dosimeter was validated for helical tomotherapy delivery QA. The basic detector characteristics were found to be satisfactory in terms of short-term reproducibility (0.1%), linearity (<0.1%), dose rate dependence (0.4%), and absolute calibration accuracy (0.4% in the center of the phantom compared with the independently calibrated diode). Relative calibration of ...

The interaction of a helical antenna, mounted on a mobile handset, with a human head phantom is investigated in this paper. Using the Genetic Algorithms (GA) technique combined with the Method of Moments (MoM), an optimization of the antenna structure is achieved regarding the input impedance at the operating frequency. The Finite Difference Time Domain (FDTD) method is then applied to simulate...

The in-beam PET camera has been operated in combination with beam tracking [2]. A homogeneous PMMA phantom was placed in the center of the field of view of the scanner and moved parallel to the two detector heads (left-right in beam’s eye view with 3 cm peak-to-peak amplitude and ≈ 3 s period). The prescribed dose was a twodimensionally spread-out Bragg-peak (SOBP) of 5×5 cm extension, centered...

We propose an empirical cupping correction (ECC) algorithm to correct for CT cupping artifacts that are induced by nonlinearities in the projection data. The method is raw data based, empirical, and requires neither knowledge of the x-ray spectrum nor of the attenuation coefficients. It aims at linearizing the attenuation data using a precorrection function of polynomial form. The coefficients ...

OBJECTIVE The aim of this study is to evaluate the effect of tissue composition on dose distribution in electron beam radiotherapy. METHODS A Siemens Primus linear accelerator and a phantom were simulated using MCNPX Monte Carlo code. In a homogeneous cylindrical phantom, six types of soft tissue and three types of tissue-equivalent materials were investigated. The tissues included muscle (sk...

We report on the reconstruction of absorption and reduced scattering coefficients of breast tissue in vivo of a patient with mastopathic disease. Distributions of times of flight of photons through the compressed breast were recorded by paraxial scanning. From data measured at four different source-detector offsets optical properties were reconstructed within the linear Rytov approximation by a...

The purpose of the present study was to evaluate the relevance of using a phantom to simulate a clinical situation where small low contrast objects are embedded in relatively homogeneous organs in order to discriminate between different ultrasound machines, taking into account human observer variability. One high-end and one general ultrasound machine using the same probe were included. Images ...

Three-dimensional printing technology has the advantage of facilitating construction complex three-dimensional shapes. For this reason, it is widely used in medical and radiological fields. However, few materials with high electron density similar to that bone exist for fabricating a human phantom. In study, commercially available filament were an FDM 3D printer perform delivery quality assuran...