LQE: Linear Quadratic Extrapolated (LQE) Dose Conversion
In reidt03/RadOnc: Analytical Tools for Radiation Oncology

LQE	R Documentation

Linear Quadratic Extrapolated (LQE) Dose Conversion

Description

This function and its associated methods calculate LQE-weighted dose(s) for a given DVH or DVH.list object, allowing iso-effect conversion between one or more DVH(s) employing different dose fractionation.

Usage

## S4 method for signature 'DVH,numeric'
LQE(x, aB, fractions = NULL, N = NULL, dose.units = c("cGy", "Gy"))

## S4 method for signature 'DVH.list,numeric'
LQE(x, aB, fractions = NULL, N = NULL, dose.units = NULL)	

## S4 method for signature 'numeric,numeric'
LQE(x, aB, fractions = NULL, N = NULL, dose.units = c("cGy", "Gy"))

Arguments

`x`	Can represent either numeric value(s) or otherwise an object of class `DVH` or `DVH.list` for which to calculate isoeffective dose(s) based on LQE. Note that input doses should be specified in units of `dose.units` (default is `"cGy"`).
`aB`	Numeric value specifying tissue-specific parameter "alpha/beta ratio". Multiple values may be specified for LQE conversion of `x`, where `x` is a `DVH.list` object containing multiple `DVH` objects.
`fractions`	Numeric value specifying the fraction sizes in which doses are deposited. Multiple values may be specified for LQE conversion of `x`, where `x` is a `DVH.list` object containing multiple `DVH` objects. Two values should be specified when `x` contains numeric value(s), with the first element representing the fractionation for the input dose and the second element used to compute iso-effective output dose. Only a single value should be used to calculate iso-effective doses for a single `DVH` input.
`N`	Numeric value specifying the number of fractions in which doses are deposited. Multiple values may be specified for LQE conversion of `x`, where `x` is a `DVH.list` object containing multiple `DVH` objects. Two values should be specified when `x` contains numeric value(s), with the first element representing the fractionation for the input dose and the second element used to compute iso-effective output dose. Only a single value should be used to calculate iso-effective doses for a single `DVH` input. Note that parameter `N` is ignored unless `fractions=NULL`.
`dose.units`	Value specifying output dose units (must be one of `"cGy"` or `"Gy"`). Note that this value also determines input dose units when `x` is numeric. Multiple values may be specified for LQE conversion of `x`, where `x` is a `DVH.list` object containing multiple `DVH` objects.

Value

Returns a DVH or DVH.list object, corresponding to original input type for parameter x.

Author(s)

Reid F. Thompson (reid.thompson@gmail.com)

References

Barendsen, G.W. (1982) Dose fractionation, dose-rate and iso-effect relationships for normal-tissue response. Int J Radiat Oncol Biol Phys 8(11):1981-1997.

Examples

# 5x 300cGy == 9x 200cGy (1800cGy isoeffective dose)
LQE(1500, aB=3, fractions=c(300, 200), dose.units="cGy")
LQE(15, aB=3, N=c(5, 9), dose.units="Gy")
LQE(18, aB=3, fractions=c(2, 3), dose.units="Gy")

# Multiple simultaneous numerical queries
LQE(c(4500, 5400), aB=3, fractions=c(300, 200), dose.units="cGy")

# DVH processing
LQE(janedoe[["LIVER"]],aB=3,fractions=200,dose.units="cGy")

# DVH list processing (default dose.units is "cGy")
plot(janedoe)
plot(LQE(janedoe,aB=3,fractions=200),col="red",new=FALSE)

reidt03/RadOnc documentation built on Sept. 29, 2022, 9:50 a.m.