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...

An accurate dose calculation in phantom and patient geometries requires an accurate description of the radiation source. Errors in the radiation source description are propagated through the dose calculation. With the emergence of linear accelerators whose dosimetric characteristics are similar to within measurement uncertainty, the same radiation source description can be used as the input to ...

The characterization of the incident photon beam is usually divided into its dependence on collimator setting (head-scatter factor) and off-axis position (primary off-axis ratio). These parameters are normally measured "in air" with a build-up cap thick enough to generate full dose build-up at the depth of dose maximum. In order to prevent any influence from contaminating electrons, it has been...

introduction: this study investigates to what extent the computed dose received by lung tissue in a commercially available treatment planning system (tps) for 192ir high-dose-rate breast brachytherapy is accurate in view of tissue inhomogeneities and presence of ribs. materials and methods: a ct scan of the breast was used to construct a patient-equivalent phantom in the clinical treatment plan...

Background: HDR brachytherapy is one of the commonest methods of nasopharyngeal cancer treatment. In this method, depending on how advanced one tumor is, 2 to 6 Gy dose as intracavitary brachytherapy is prescribed. Due to high dose rate and tumor location, accuracy evaluation of treatment planning system (TPS) is particularly important. Common methods used in TPS dosimetry are based on computat...

Dose distributions of (192)Ir HDR brachytherapy in phantoms simulating water, bone, lung tissue, water-lung and bone-lung interfaces using the Monte Carlo codes EGS4, FLUKA and MCNP4C are reported. Experiments were designed to gather point dose measurements to verify the Monte Carlo results using Gafchromic film, radiophotoluminescent glass dosimeter, solid water, bone, and lung phantom. The re...

introduction:  90 sr/ 90 y source  has  been  used  for  the  intravascular  brachytherapy  to  prevent  coronary  restenosis in the patients who have undergone angioplasty. the aim of this research is to determine the  dose distribution of  90 sr/ 90 y source in a water phantom.  materials  and  methods:  in  the  present  work,  mcnp  code  has  been  applied  to  calculate  the  dose  distri...

Dose distribution inside the human body due to external photon exposure was measured. Radiation detectors were imaging plate (IP) sheets and thermoluminescent dosimeters (TLD). Each IP sheet was installed between horizontally sliced pieces of a rando-phantom. TLDs were also installed inside/around the position of a target organ of the phantom. The rando-phantom was exposed to a photon beam of C...

The post-implantation dosimetry for brachytherapy using Monte Carlo calculation by EGS5 code combined with the source strength regression was investigated with respect to its validity. In this method, the source strength for the EGS5 calculation was adjusted with the regression, so that the calculation would reproduce the dose monitored with the glass rod dosimeters (GRDs) on a water phantom. T...

Phantoms for radiation dosimetry, including physical phantoms for radiological use in medicine in particular, were introduced as early as the 1910s [1] while those for radiation protection dosimetry started to evolve in the late 1950s. This innovation was driven partly from the consensus that dose quantity for protection purposes should be assessed in “receptor conditions” instead of the tradit...