The purpose of this study was to examine the dose enhancement at bone-implant interfaces from scattered radiation during simulated head and neck radiotherapy. Three cylindric implant systems with different compositions (pure titanium, titanium-aluminum-vanadium alloy, titanium coated with hydroxyapatite) and a high gold content transmandibular implant system (gold-copper-silver alloy) were stud...

Presence of interfaces between high and low atomic number (Z) materials, often encountered in diagnostic imaging and radiation therapy, leads to radiation dose perturbation. It is characterized by a very narrow region of sharp dose enhancement at the interface. A rapid falloff of dose enhancement over a very short distance from the interface makes the experimental dosimetry nontrivial. We use a...

background: pet/ct imaging using [18f]-fdg is utilized in clinical oncology for tumor detecting, staging and responding to therapy procedures. essential consideration must be taken for radiation staff due to high gamma radiation in pet/ct and cyclotron center. the aim of this study was to assess the staff exposure regarding whole body and organ dose and to evaluate environment dose in pet/ct an...

Introduction: Currently, the potential application of gold nanoparticles (AuNPs) to increase the efficiency of radiation therapy have been investigated. However, the loss of an appropriate method to estimate the dose distribution in nanoparticle laden tissue limits the applicability of nanoparticles in radiotherapy clinics. Polymer gel dosimetry provides an accurate and precise...

Introduction: To increase the radiation therapy efficiency, two approaches have been employed which include increasing the dose delivery or modifying the biological response to ionizing radiation. This study aimed to modify the biological response to ionizing radiation by combination therapy using radio-sensitizer agent and anticancer drug. Materials and Methods:</str...

background; environmental gamma ray refers to the gamma radiation from terrestrial sources and building materials. in enclosed spaces radiation can become a health hazard leading to potential increase in the rates of lung cancer. the goal of this study is to assess the exposure to natural gamma radiation of children in the schools of zanjan province. method; the natural gamma radiation was asse...

introduction guilan is one of the provinces in north of iran, with population of 2,480,874 and a total area of ​​14,042 square kilometers. this study assesses the outdoor natural gamma dose rates in the air of 49 cities in guilan and calculates corresponding average annual effective dose. materials and methods a total of 260 different sample points measurements were carried out. the results inc...

background: gold nanoparticles (gnps) have been shown as a good radiosensitizer. in combination with radiotherapy, several studies with orthovoltage x-rays have shown considerable dose enhancement effects. this paper reports the dose enhancement factor (def) due to gnps in 18 megavoltage (mv) beams. materials and methods: different geometrical 50-nm gnps configurations at a concentration of 5 m...

Introduction: Theranostics, in particular, the use of radionuclides with the capability of simultaneous imaging and treatment has opened new horizons in personalized treatment planning of targeted radiation therapy. In this approach, positive beta or gamma emitters are required for imaging and alpha, beta and Auger electrons for treatment purpose. On the other hand, studies hav...