PURPOSE To compare contrast enhancement per unit of dose of contrast medium in MR imaging at 0.5 and 1.5 T. METHODS Contrast enhancement in images made at 0.5 and 1.5 T after 0.1 mmol/kg of gadopentetate dimeglumine and 0.3 mmol/kg of gadodiamide was measured and the degree of contrast enhancement in the cavernous sinus and pituitary gland compared. RESULTS At both field strengths and both ...

PURPOSE The aim of this study is evaluation of the effect of diameter of (10)B nanoparticles and various neutron capture cross-section libraries on macroscopic dose enhancement in boron neutron capture therapy (BNCT). MATERIAL AND METHODS MCNPX Monte Carlo code was used for simulation of a (252)Cf source, a soft tissue phantom and a tumor containing (10)B nanoparticles. Using (252)Cf as a neu...

MRI is often used in tumor localization for radiotherapy treatment planning, with gadolinium (Gd)-containing materials often introduced as a contrast agent. Motexafin gadolinium is a novel radiosensitizer currently being studied in clinical trials. The nanoparticle technologies can target tumors with high concentration of high-Z materials. This Monte Carlo study is the first detailed quantitati...

Objective(s): Normoxic MAGIC-f polymer gels are established dosimeters used for three dimensional dose quantifications in radiotherapy. Nanoparticles with high atomic number such as gold are novel radiosensitizers used to enhance doses delivered to tumors. The aim of this study was to investigate the effect of gold nanoparticles (GNPs) in enhancing percentage depth doses (PDDs) within the MAGIC...

This study investigated radiation dose variations in pre-clinical irradiation due to the photon beam energy and presence of tissue heterogeneity. Based on the same mouse computed tomography image dataset, three phantoms namely, heterogeneous, homogeneous and bone homogeneous were used. These phantoms were generated by overriding the relative electron density of no voxel (heterogeneous), all vox...

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...

We have calculated the dose enhancements close to metal implants in Gamma Knife radiosurgery using different beam sizes, i.e., 4, 8 and 18 mm collimator helmets sin addition to the previous calculations using the 14 mm collimator helmetd. For the 8 and 18 mm helmets, the obtained results were similar to those obtained using the 14 mm helmet, which can be explained by the similar beam profiles w...