Entrance and exit doses are commonly measured in in vivo dosimetry for comparison with expected values, usually generated by the treatment planning system (TPS), to verify accuracy of treatment delivery. This report aims to evaluate the accuracy of six TPS algorithms in computing entrance and exit doses for a 6 MV beam. The algorithms tested were: pencil beam convolution (Eclipse PBC), analytic...

The main objective of this study was to assess factors affecting early entrance and later exit of herders from summer rangelands. The study population consisted of heads of Nomads in Kouhdasht region, Lorestan province, Iran. According to Cochran formula among 1038 Nomadic families, 310 families were selected with stratified random sampling in 2015. In order to assess validity, expert's opinion...

Accuracy in the delivered dose to the patients plays an important and vital role in radiotherapy treatments. This happens because of steep gradient of dose-local control and dose-normal tissue complication probability curves. Dosimetric uncertainty of 3%-4% (one standard deviation) in the delivered dose to the target volume as an acceptable level has been recommended(1-3). In many centers, in v...

background: in vivo dosimetry is a method for estimation of overall error in the delivered dose to the patients at the end of radiotherapy process. in this research, two methods for target dose calculation were evaluated on midline and central axis of photon beams in in vivo dosimetry of thorax fields. materials and methods: entrance and exit doses for anterior and lateral fields of thorax were...

We consider cold collisions of OH molecules in the P3/2 ground state, under the influence of a magnetic field. We find that modest fields of several thousand gauss can act to suppress inelastic collisions of weakfield-seeking states by two orders of magnitude. We attribute this suppression to two factors: sid an indirect coupling of the entrance and the exit channel, in contrast to the effect o...

PURPOSE To quantify the clinically observed dose enhancement adjacent to cranial titanium fixation plates during post-operative radiotherapy. METHODS Irradiation of a titanium burr hole cover was simulated using Monte Carlo code MCNPX for a 6 MV photon spectrum to investigate backscatter dose enhancement due to increased production of secondary electrons within the titanium plate. The simulat...

Background: In vivo dosimetry is a method for estimation of overall error in the delivered dose to the patients at the end of radiotherapy process. In this research, two methods for target dose calculation were evaluated on midline and central axis of photon beams in in vivo dosimetry of thorax fields. Materials and Methods: Entrance and exit doses for anterior and lateral fields of thorax were...

Knowledge of a spectrograph slit function is necessary to interpret unresolved lines and spectral features in an observed spectrum. In a scanning spectrometer with a single exit slit, the slit function is easily measured by illuminating the entrance slit with a broadband source and scanning the dispersive element. In a fixed grating/or disperser spectrograph, the slit functions have been measur...

We introduce a compact submicron structure consisting of multiple optical microcavities at both the entrance and exit sides of a subwavelength plasmonic slit filled with an absorbing material. We show that such microcavity structures at the entrance side of the slit can greatly enhance the coupling of the incident light into the slit, by improving the impedance matching between the incident pla...