introduction radiotherapy is regarded as the first treatment of choice for nasopharyngeal carcinoma. despite the advantages of radiotherapy, patients may suffer from a wide range of side-effects due to the presence of many sensitive normal tissues in these regions. if the absorbed dose exceeds the tolerance level in parotid glands and the spinal cord, myelopathy, lhermitte's sign and xeros...

orthopantomography is a well-established imaging technique in dental diagnosis. although its exposure to individuals is relatively low compared to other diagnostic radiology examinations, it is still the most frequent x-ray examination. so it is important to estimate absorbed dose to critical organs in this examination. the present study was designed to determine the radiation doses to eyes, pa...

background: radiotherapy plays an important role in the management of most malignant and many benign primary central nervous system (cns) tumors. radiotherapy affects both tumor cells and uninvolved normal cells; so, it is important to estimate absorbed dose to organs at risk in this kind of treatment. the aim of this study was to determine the absorbed dose to chiasma, lens, optic nerve, retin...

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....

Solid water is often the phantom material of choice for dosimetry procedures in radiotherapy high-energy X-ray and electron beam radiation calibration and quality assurance. This note investigates variation in heat conduction that can occur for a common commercially available solid water stack phantom when a temperature differential occurs between the phantom and ambient temperature. These vari...

PURPOSE To develop a projection quality-driven tube current modulation method in cone-beam computed tomography for image-guided radiotherapy based on the prior attenuation information obtained by the planning computed tomography and then evaluate its effect on a reduction in the imaging dose. MATERIALS AND METHODS The QCKV-1 phantom with different thicknesses (0-400 mm) of solid water upon it...

Fricke gel dosimetry is a valuable method for in-phantom dose measurements in complex irradiation modalities like IMRT and BNCT. Implementation of this dosimetry technique requires dedicated instruments capable of measuring and further analysis immediately in situ at the radiation facility. This work presents a novel and integral dosimetry system aimed to attain portability requirements. The me...

In treatment planning of brachytherapy, absorbed dose is calculated by superposing predetermined distributions of absorbed dose to water in water for the single source according to the irradiation pattern ͓i.e., placement of the source͑s͒ or dwelling position͑s͔͒. Single-source reference water data are derived from Monte Carlo ͑MC͒ simulations and/or experiments. For reasons of positional accuracy, exp...

This study presents the application of the Presage/optical-CT 3D dosimetry system for relative dosimetry in the Radiologic Physics Center (RPC) Head and Neck (H&N) IMRT phantom. Performance of the system was evaluated by comparison with the "gold-standard" RPC credentialing test. A modified Presage cylindrical insert was created that extended the capability of the RPC H&N phantom to 3D dosimetr...

Introduction: Total Skin Electron Therapy (TSET) and Total Body Irradiation (TBI) are kinds of treatment which use electron and photon beams to treat special types of cancers. The aim of these techniques are to deliver uniform dose to the entire skin while minimizing delivered dose to organs at risk. To check the homogeneity of dose delivery in TBI and TSET, using a humanoid ph...