# TRANSITION ZONE DOSIMETRY

> **NIH NIH R01** · UNIVERSITY OF MINNESOTA · 1989 · $120,884

## Abstract

The dose distribution of a therapeutic photon or electron beam in the
vicinity of a medium interface (muscle/bone, tissue/lung, tissue/shielding
or medium/dosimeter) is affected by the exchange of scattered photons,
scattered electrons and bremsstrahlung photons between the medium with the
higher atomic number and the medium with the lower atomic number.  In the
case of a shielding interface in tissue, a therapeutic electron beam dose
distribution can be enhanced by 20 to 60%, and the perturbation can be
detected several cm from the interface.

In this research project we will develop mathematical models to describe
the perturbation of photon and electron beam dose distributions in the
vicinity of single interfaces, multiple interfaces, interfaces that may be
parallel to or at an angle to the beam axis and interfaces having
cylindrical or spherical symmetry.  For electron beams, this work will
result in improvements in theory of beam spreading, depth dose curves, the
effects of collimator scatter, and in the definition of effective depth.

The research program will investigate the following major components of
electron beams:  1) the primary electrons (using the fluence transformation
method), 2) the diffusion electrons (which originate in the primary
distribution), 3) the secondary electrons, 4) the bremsstrahlung photons.
For photon beams:  1) the distribution of scattered photons, and 2) the
electrons set in motion by the photons.

Comparisons with dose perturbation measurements already reported in the
literature and further experimental and Monte Carlo verification will be
made.

## Key facts

- **NIH application ID:** 3176247
- **Project number:** 5R01CA038180-06
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **SAM.gov UEI:** KABJZBBJ4B54
- **Principal Investigator:** BARRY L WERNER
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 1989
- **Award amount:** $120,884
- **Award type:** 5
- **Project period:** 1984-08-01 → 1991-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/3176247

## Citation

> US National Institutes of Health, RePORTER application 3176247, TRANSITION ZONE DOSIMETRY (5R01CA038180-06). Retrieved via MORVS 2026-10-25 from https://api.morvs.ai/grant/nih/3176247. Licensed CC0.

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