LQE {RadOnc}

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 ([e-mail])

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.

See Also

DVH, DVH.list

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)