TY - JOUR
T1 - Radiation treatment dose optimisation using Poisson tumour control probability parameters
AU - Cho, G. A.
AU - Ebert, M. A.
AU - Holloway, L.
AU - Kuncic, Z.
AU - Baldock, C.
AU - Thwaites, D. I.
N1 - Copyright the Author(s). First published in Journal of physics : conference series 489 article 012047. The original publication is available at doi:10.1088/1742-6596/489/1/012047, published by IOP Publishing. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.
PY - 2014
Y1 - 2014
N2 - This study examines the Poisson tumour control probability (TCP) γ₃₇ and D₃₇ parameters of a uniformly irradiated numerical tumour model using changes in tumour burden as a surrogate for treatment response information. An optimum dose Di for a tumour sub-volume element Vi is described that maximizes TCP as a function of fixed tumour integral dose ξ. TCP was calculated for spatially-varying clonogen density for a total 10⁸ cells and radiosensitivity α with mean radiosensitivity in the range 0.4-1.0 Gy⁻¹. A bivariate normal distribution is used to describe the radiosensitivity α and the linear term of the linear-quadratic (LQ) cell kill governed the changes in the regional tumour burden within sub-volumes Vi. The optimum dose distribution, Di, for Vi is obtained as a function of fixed tumour integral dose ξ. For a uniform dose delivery and for TCP = 37%, γ₃₇ and D₃₇ are described by the effective radiosensitivity αeff and the effective clonogen number N0eff, respectively. αeff is equivalent to differential dose changes in the number of clonogenic cells (tumour burden). The γ₃₇ values were found to be inversely correlated with variance of the probability density function of the α distribution. For the biologically optimum dose distribution, γ₃₇ was found to converge to the theoretical maximum limit and D₃₇ was found to reduce relative to that obtained for the uniform dose case. The TCP parameters γ₃₇ and D₃₇ could thus be useful in optimising individual radiation treatment doses even when tumour heterogeneity is taken into account.
AB - This study examines the Poisson tumour control probability (TCP) γ₃₇ and D₃₇ parameters of a uniformly irradiated numerical tumour model using changes in tumour burden as a surrogate for treatment response information. An optimum dose Di for a tumour sub-volume element Vi is described that maximizes TCP as a function of fixed tumour integral dose ξ. TCP was calculated for spatially-varying clonogen density for a total 10⁸ cells and radiosensitivity α with mean radiosensitivity in the range 0.4-1.0 Gy⁻¹. A bivariate normal distribution is used to describe the radiosensitivity α and the linear term of the linear-quadratic (LQ) cell kill governed the changes in the regional tumour burden within sub-volumes Vi. The optimum dose distribution, Di, for Vi is obtained as a function of fixed tumour integral dose ξ. For a uniform dose delivery and for TCP = 37%, γ₃₇ and D₃₇ are described by the effective radiosensitivity αeff and the effective clonogen number N0eff, respectively. αeff is equivalent to differential dose changes in the number of clonogenic cells (tumour burden). The γ₃₇ values were found to be inversely correlated with variance of the probability density function of the α distribution. For the biologically optimum dose distribution, γ₃₇ was found to converge to the theoretical maximum limit and D₃₇ was found to reduce relative to that obtained for the uniform dose case. The TCP parameters γ₃₇ and D₃₇ could thus be useful in optimising individual radiation treatment doses even when tumour heterogeneity is taken into account.
UR - http://www.scopus.com/inward/record.url?scp=84899499198&partnerID=8YFLogxK
U2 - 10.1088/1742-6596/489/1/012047
DO - 10.1088/1742-6596/489/1/012047
M3 - Conference paper
SN - 1742-6588
VL - 489
SP - 012047-1-012047-6
JO - Journal of Physics: Conference Series
JF - Journal of Physics: Conference Series
IS - 1
M1 - 012047
T2 - International Conference on the Use of Computers in Radiation Therapy (17th : 2013)
Y2 - 6 May 2013 through 9 May 2013
ER -