background: the heterogeneous composition of the human body presents numerous tissue types and cavities with widely differing radiologic properties. the aim of the present work was to develop a low cost homogeneous and heterogeneous phantom and the absorbed dose were measured by ionization chamber for different radiotherapy treatment techniques and compared with treatment planning system absorb...

Radiotherapy treatment planning integrating positron emission tomography (PET) and computerized tomography (CT) is rapidly gaining acceptance in the clinical setting. Although hybrid systems are available, often the planning CT is acquired on a dedicated system separate from the PET scanner. A limiting factor to using PET data becomes the accuracy of the CT/PET registration. In this work, we us...

Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid ph...

Purpose Functional magnetic resonance imaging (fMRI) during infancy poses challenges due to practical, methodological, and analytical considerations. The aim of this study was implement a hardware-related approach increase subject compliance for fMRI involving awake infants. To accomplish this, we designed, constructed, evaluated an adaptive 32-channel array coil. Methods allow with close-fitti...

Background: Photon attenuation as an inevitable physical phenomenon influences on the diagnostic information of SPECT images and results to errors in accuracy of quantitative measurements. This can be corrected via different physical or mathematical approaches. As the correction equation in mathematical approaches is nonlinear, in this study a new method of linearization called ‘Piece ...

INTRODUCTION A physical 3-dimensional phantom that simulates PET/SPECT images of static regional cerebral blood flow in grey matter with a realistic head contour has been developed. This study examined the feasibility of using this phantom for evaluating PET/SPECT images. METHODS The phantom was constructed using a transparent, hydrophobic photo-curable polymer with a laser-modelling techniqu...

An investigation of the radiation from 5 different phones next to two head phantoms proposed for radiation measurements has been carried out and the radiation has been evaluated thru the Total Radiated Power, the Total Receiver Sensitivity and the Mean Effective Gain. The investigation is based on measurements of the farfield patterns measured in an anechoic room using a system tester to avoid ...

Target audience: Radiofrequency (RF) engineers, anyone interested in high field RF coils, parallel transmit or high field brain imaging. Introduction: Electric dipole antennas are seeing increasing use for 7T MR imaging. They differ from conventional surface coil loops in many ways. With 8 elements surrounding a body sized tissue equivalent phantom and array of dipole antennas can achieve highe...

A straightforward method is presented to estimate peak skin doses (PSDs) delivered by computed tomography (CT) scanners. The measured PSD values are related to the well-known volume CT dose index (CTDI(vol)), displayed on the console of CT scanners. PSD measurement estimates were obtained, in four CT units, by placing radiochromic film on the surface of a CTDI head phantom. Six different X-ray ...

AMPUTATED LIMBS persist as "phantoms" in their owners' consciousness. Temporary or permanent severance of afferent pathways may also give rise to subjective experiences in which the position of the phantom limb is different from that of the real one. Attempts have been made to explain phantom phenomena as expressions of a "body image" or "body schema" subserving a preconscious neurophysiologica...