Effect of variable dose rate on biologically effective dose.

Int J Radiat Biol

Department of Radiation Oncology, Halifax Health , Daytona Beach, Florida.

Published: November 2013

Purpose: To investigate the effect of variable dose rate on biologically effective dose (BED).

Materials And Methods: By using the linear-quadratic (LQ) model with bi-exponential repair, we analytically determine the time-dependent dose rate [Formula: see text] which minimizes the effective protraction factor (Geff) and BED under the condition of fixed fraction time and dose per fraction. Because normal tissue complication probability (NTCP) monotonically decreases with decreasing BED, the dose rate [Formula: see text] also minimizes NTCP.

Results: The dependences of Geff , BED and NTCP on fraction time were determined for different radiobiological parameters and two different dose rates: constant dose rate R0 and varying dose rate [R].

Conclusion: The results of this study indicate that under certain conditions the reduction in BED for late-responding tissues due to increased fraction time can be significantly greater than the reduction in BED for tumors. Our analysis also indicates that dose rate optimization can be radiobiologically beneficial because of the resulting decrease in NTCP.

Download full-text PDF

Source
http://dx.doi.org/10.3109/09553002.2013.811308DOI Listing

Publication Analysis

Top Keywords

dose rate
28
fraction time
12
dose
10
variable dose
8
rate biologically
8
biologically effective
8
effective dose
8
rate [formula
8
[formula text]
8
text] minimizes
8

Similar Publications

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!