introduction: multiple fields and presence of heterogeneities create complex dose distributions that need three dimensional dosimetry. in this work, we investigated mr-based magic gel dosimetry as a three-dimensional dosimetry technique to measure the delivered dose to bladder and rectum in prostate radiation therapy. materials and methods: a heterogeneous slab phantom including bones was made....

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...

The water phantom is used for LINAC calibration to measure absorbed dose radiation. Practically, it requires a long preparation time and considered less efficient. To increase efficiency, the medical physics team in hospital uses slab as tool. Consequently, correction factor crucial define equivalence of doses resulted from phantom. measurement was performed according IAEA TRS-398 dosimetry pro...

A model has been developed based on random walk theory that allows the diffusion of light along a principal axis to differ from that in orthogonal directions. We present expressions that describe the time-resolved intensity measured across a slab and on the surface of a semi-infinite medium for a principal axis oriented parallel or perpendicular to the surface. The model of time-resolved transm...

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...