Related Experiment Video
Updated: Oct 1, 2025

Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
A unified formalism for estimating photon absorbed fractions in spherical biovolumes: analytical equations without
Tatiana G Sazykina1, Alexander I Kryshev1
1Research & Production Association 'Typhoon', Obninsk, Kaluga Region, Russia.
Abstract:
A new analytical formalism, previously developed for estimating electron-absorbed fractions, was extended for estimating photon absorbed fractions in soft-tissue spheres, containing uniformly distributed photon-emitter. Analytical equations were formulated for calculating values of photon-absorbed fractions. The method involves a rescaling procedure with transformation of real biological sizes to unitless effective ones, combining information of photon energy, object's size, and material. Rescaling was applied to large published datasets of photon absorbed fractions in soft-tissue spheres, computed with Monte Carlo codes. A new effect was demonstrated in which the rescaled data formed a single smooth 'unified curve' with saturation. The unified curve for photon absorbed fractions was described analytically, using simple equations without fitting parameters. The new method was tested for a wide range of spheres-from 1 mg up to 1000 kg, and wide range of photon energies-from 0.02 up to 5 MeV. For larger spheres, a close agreement between analytical values and Monte Carlo datasets was demonstrated. For small biovolumes, analytical equations predict higher values than available Monte Carlo data. The unified formalism is now available for direct calculating radiation absorbed fractions in soft-tissue spherical organs and organisms without Monte Carlo codes.
Related Concept Videos
UV–Vis Spectroscopy: Beer–Lambert Law
One-Compartment Open Model: Wagner-Nelson and Loo Riegelman Method for ka Estimation
On...
Absorption of Radiation
Noncompartmental Analysis: Miscellaneous Pharmacokinetic Parameters
One key aspect of the noncompartmental approach is determining a drug's total clearance. This can be done by dividing the drug dose by the area under the concentration-time curve from zero to infinity. The area under the concentration-time curve represents the drug's...
Estimation of the Physical Quantities
Fundamental Mathematical Principles in Pharmacokinetics: Mathematical Expressions and Units
One significant application of mathematics in pharmacokinetics is the characterization of drug distribution through the volume of distribution...

