Professional
Technical
IVT
homogeneity index
Also written as: HI — Homogeneity Index
A quantitative measure of dose uniformity within the target volume, calculated as the ratio of maximum to minimum dose.
Full Definition
The homogeneity index (HI) is a dosimetric parameter used to evaluate how evenly radiation dose is distributed throughout the planning target volume. It is typically calculated as (D2% - D98%)/D50% where D2%, D98%, and D50% represent doses delivered to 2%, 98%, and 50% of the target volume respectively. A lower HI value indicates more homogeneous dose distribution. This metric is particularly important in stereotactic treatments where dose gradients can be steep.
Usage
Usage note: Always lowercase 'index' when spelling out the full term.
In Context
- "The treatment plan achieved a homogeneity index of 1.08, meeting institutional guidelines." — Treatment planning report
- "Homogeneity index values exceeding 1.2 may indicate suboptimal dose distribution." — Quality assurance documentation
Also known as
dose homogeneity
HI
Contrasted with
dose heterogeneity
Don't confuse with
conformity index
conformality index