BACKGROUND Electroencephalography (EEG) can capture the cortical response evoked by transcranial magnetic stimulation (TMS). The TMS pulse provokes a large artefact, which obscures the cortical response in the first milliseconds after TMS. Removing this artefact remains a challenge. METHODS We delivered monophasic and biphasic TMS to a melon as head phantom and to four healthy participants an...

computed tomographyrepresents about 10% of all diagnostic radiology procedures, but it isresponsible for almost 50% - 60% of exposure from diagnostic procedures. inhead ct, other critical organs such as eye lenses and thyroids are in theradiation field. therefore, dose assessment in these organs is very important.the aim of this study is to estimate the absorbed dose in critical organs ofpatien...

Introduction The Gamma Knife system is designed solely for non-invasive treatment of brain disorders, and it benefits from stereotactic surgical techniques. Dose calculations required in the system are performed by GammaPlan code; in this code, brain tissue is considered uniform. In the present study, we evaluated the effect of Gamma Knife system on the obtained dose through simulating a real ...

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 wise line...

An important step in the verification of the reliability of portal films as in vivo dosemeters is the evaluation of the agreement between exit dose profiles and optical density profiles measured on the portal film. To test the possibilities of a conventional portal film system in 60Co beams suitable for head and neck irradiation, we verified the agreement between relative exit doses (measured b...

The aim of this study was to demonstrate the role of advanced fabrication technology across a broad spectrum of head and neck surgical procedures, including applications in endoscopic sinus surgery, skull base surgery, and maxillofacial reconstruction. The initial case studies demonstrated three applications of rapid prototyping technology are in head and neck surgery: i) a mono-material parana...

Optical tomography is being developed at UCL as a tool for understanding the mechanisms of haemorrhagic and hypoxic-ischaemic brain injury and assessing the effectiveness of novel neural rescue therapies in the newborn infant. Our 32-channel time-resolved optical imaging system measures photon flight times between multiple pairs of points on the surface of the head, and images sensitive to loca...

The peak SAR values of two-element array antennas for mobile handsets in the vicinity of a spherical phantom of a human head are evaluated numerically as a function of the distance between the array antenna and the head phantom when the two elements of a two-element array antenna are either co-phase voltage-fed or reverse-phase voltage-fed. It is found that relation between the worst case of th...

introduction:  image  distortion  is  one  of  the  major  problems  of  magnetic  resonance  imaging  (mri) for use in 3dmri, velocity mri, fmri and radiotherapy treatment planning (rttp). it is  widely known that the most obvious effect of the inhomogenity of the magnetic fields and the  nonlinearity  of  the  gradient  is  the  geometric  distortion  of  mr  tomograms.  in  this  study,  the...

PURPOSE This study aimed to provide comparative measurements of the effective dose from direct and indirect digital panoramic units according to phantoms and exposure parameters. MATERIALS AND METHODS Dose measurements were carried out using a head phantom representing an average man (175 cm tall, 73.5 kg male) and a limbless whole body phantom representing an average woman (155 cm tall, 50 k...