PURPOSE To compare the dose and image quality of three methods for reducing the radiation dose to the eye at head computed tomography (CT): bismuth shielding, organ-based tube current modulation (TCM), and global reduction of the tube current. MATERIALS AND METHODS An anthropomorphic head phantom was scanned under six conditions: (a) without any dose reduction techniques (reference scanning);...

For determining the absorbed dose of ionizing radiation is tissues, it is essential to have materials which behave like tissues. These kinds of materials are usually called phantom. Up to now many different compounds like water, rubber, Perspex etc have been used. Unfortunately, the practical use of each of them has had its own problems. Our suggested gelatin phantom is very similar to soft...

The aim of this study was to investigate the potential of jaw tracking with the volumetric-modulated arc therapy (VMAT) to reduce the normal tissue dose. Plans of nasopharynx, lung, and prostate cancers (10 plans for each) were used to perform VMAT with and without jaw tracking. The dose reduction was evaluated in terms of organ doses and integral doses. Organ-dose reduction with jaw tracking w...

Background: Most preclinical studies are carried out on mice. For internal dose assessment of a mouse, specific absorbed fraction (SAF) values play an important role. In most studies, SAF values are estimated using older standard human organ compositions and values for limited source target pairs.Objective: SAF values for monoenergetic photons of energies 15, 50, 100, 500, 1000 and 4000 keV...

This work presents internal dosimetry estimates for diagnostic procedures performed for thyroid disorders by relevant radiopharmaceuticals. The organ doses for (131)Iodine, (123)Iodine and (99m)Tc incorporated into the body were calculated for the International Commission on Radiological Protection (ICRP) reference voxel phantoms using the Monte Carlo transport method. A comparison between diff...

OBJECTIVES The impact of corticosteroids on the risk of organ damage in the context of clinical end points endorsed in some systemic lupus erythematosus (SLE) clinical trials is underexplored. METHODS We analysed data from the Hopkins Lupus Cohort using Cox proportional hazards models to understand the impact of exposure to different corticosteroid doses on the risk of developing any new orga...

introduction:the use of beta emitters is one of the effective methods for palliation of bone metastasis. the risk of normal tissue toxicity should be evaluated in the bone pain palliation treatment. methods: in this study, the monte carlo simulation code mcnpx was used for simulation a bone phantom model consisted of bone marrow, bone and soft tissue. specific absorbed fractions were calculated...