UNLABELLED As one of the major organs of the excretory pathway, the kidneys represent a frequent source of radiopharmaceutical uptake in both diagnostic and therapeutic nuclear medicine. The unique organization of the functional tissues of the organ ensures transient changes in suborgan localization of renal activity. Current single-region dosimetric models of the kidneys, however, force the as...

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...

BACKGROUND To date, the estimated radiation-absorbed dose to organs and tissues in patients undergoing diagnostic examinations in nuclear medicine is derived via calculations based on models of the human body and the biokinetic behaviour of the radiopharmaceutical. An internal dosimetry computer program, IDAC-Dose2.1, was developed based on the International Commission on Radiological Protectio...

The specific absorbed fraction (SAF) of energy is an essential element of internal dose assessment. Here reported a set of SAFs calculated for selected organs of a human voxel-based phantom. The Monte Carlo transport code GATE version 6.1 was used to simulate monoenergetic photons and electrons with energies ranging from 10 keV to 2 MeV. The particles were emitted from three source organs: kidn...

UNLABELLED Dose assessment to active bone marrow is a critical feature of radionuclide therapy treatment planning. Skeletal dosimetry models currently used to assign radionuclide S values for clinical marrow dose assessment are based on bone and marrow cavity chord-length distributions. Accordingly, these models cannot explicitly consider energy loss to inactive marrow (adipose tissue) during p...

The purpose of this study was to validate an analytical expression for the absorbed-dose calculation from the spherical source of beta-emitting radionuclides and to apply it to micrometastases treated with radiolabeled monoclonal antibodies. The self-absorbed fractions from I-131 and P-32 uniform spherical sources were calculated using the analytical expression introduced by P. K. Leichner (J. ...

Electromagnetic energy incident on the surface features are partially reflected, absorbed or transmitted through it. The fractions that are reflected absorbed or transmitted vary with material type and the condition of the feature. It also varies with the wavelength of the incident energy. Majority of the remote sensing systems operate in the region in which the surface features mostly reflect ...

Rats at various ages were observed to present with different radiosensitivity and bioavailability for radiotracers commonly used in preclinical research. We evaluated the effect of age-induced changes in body weight on radiation dose calculations. A series of rat models at different age periods were constructed based on the realistic four-dimensional digital rat whole-body (ROBY) computational ...

To study whether cholesterol is absorbed by the gallbladder, we instilled from 1 to 300 nmoles of [4-14C]cholesterol dissolved in 1 ml of guinea pig bile into the in situ guinea pig gallbladder. The bile used in these experiments contained 7 mumole/ml bile acid, 27 nmole/ml lecithin, and 8 nmol/ml cholesterol. To this bile, we added the radioactive cholesterol, from 0 to 1 mumole/ml egg lecithi...

There has been a considerable accumulation of usage of voxel models for internal radiation dosimetry (Xu & Eckerman, 2009 ; Zaidi & Tsui, 2009). The human voxel models of the Reference Male and Reference Female have been introduced and used to evaluate the energy deposition in organs resulting from internal radiation exposures by the International Commission on Radiological Protection (ICRP) (I...