Impact of dose and sensitivity heterogeneity on TCP
2014 (English)In: Computational & Mathematical Methods in Medicine, ISSN 1748-670X, E-ISSN 1748-6718, 182935Article in journal (Refereed) Published
Purpose.The combined influence of heterogeneity in dose and radiation sensitivity on the probability of tumor control has not yet been fully explored, neither by numerical simulations nor by analytical modeling. The present paper adds to the current experience and presents an analytical description and numerical simulations of the influence of macroscopic intercell dose variations and intercell sensitivity variations on the probability of controlling the tumor. Methods. Computer simulations of tumour control probability (TCP) accounting for heterogeneity in dose and radiation sensitivity were performed based on Bernoulli trials including cell repopulation during the course of treatment in an explicit manner, without performing approximations.The dose heterogeneity was simulated by random sampling from a normal distribution with a specified mean dose and standard deviation. Two scenarios were considered for the simulation of intercell heterogeneity of the sensitivity described by the parameters of the linear-quadratic model (LQ) for cell killing. An analytical expression for TCP accounting for heterogeneity in sensitivity was also proposed and validated against simulations. Results. The results show good agreement between numerical simulations and the calculated TCP using the proposed analytical expression for the case of a heterogeneous dose and sensitivity distributions.When the intercellular variations of dose and sensitivity are taken into account, the total dose required for achieving the same level of control as for the case of homogeneous distribution is only slightly higher, the influence of the variations in the two factors taken into account being additive. For the case of interpatient variations in dose and sensitivity, the combined effects result in a coefficient of synergy of less than one. Conclusions.The results of this study show that the interplay between cell or tumor variation in the sensitivity to radiation and the inherent heterogeneity in dose distribution is highly complex and therefore should be taken into account when predicting the outcome of a given treatment.
Place, publisher, year, edition, pages
Tumor control probability, Sensitivity variation, Dose Heterogeneity, Modeling
Cancer and Oncology
Research subject Medical Radiation Physics
IdentifiersURN: urn:nbn:se:su:diva-102700DOI: 10.1155/2014/182935ISI: 000336273000001OAI: oai:DiVA.org:su-102700DiVA: diva2:712660