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Extrapolation of normal tissue complication probability for different fractionations in liver irradiation. Int J Radiat Oncol Biol Phys 2009 May 01;74(1):283-9

Date

03/18/2009

Pubmed ID

19289259

DOI

10.1016/j.ijrobp.2008.11.029

Scopus ID

2-s2.0-64049108293   19 Citations

Abstract

PURPOSE: The ability to predict normal tissue complication probability (NTCP) is essential for NTCP-based treatment planning. The purpose of this work is to estimate the Lyman NTCP model parameters for liver irradiation from published clinical data of different fractionation regimens. A new expression of normalized total dose (NTD) is proposed to convert NTCP data between different treatment schemes.

METHOD AND MATERIALS: The NTCP data of radiation- induced liver disease (RILD) from external beam radiation therapy for primary liver cancer patients were selected for analysis. The data were collected from 4 institutions for tumor sizes in the range of of 8-10 cm. The dose per fraction ranged from 1.5 Gy to 6 Gy. A modified linear-quadratic model with two components corresponding to radiosensitive and radioresistant cells in the normal liver tissue was proposed to understand the new NTD formalism.

RESULTS: There are five parameters in the model: TD(50), m, n, alpha/beta and f. With two parameters n and alpha/beta fixed to be 1.0 and 2.0 Gy, respectively, the extracted parameters from the fitting are TD(50)(1) = 40.3 +/- 8.4Gy, m =0.36 +/- 0.09, f = 0.156 +/- 0.074 Gy and TD(50)(1) = 23.9 +/- 5.3Gy, m = 0.41 +/- 0.15, f = 0.0 +/- 0.04 Gy for patients with liver cirrhosis scores of Child-Pugh A and Child-Pugh B, respectively. The fitting results showed that the liver cirrhosis score significantly affects fractional dose dependence of NTD.

CONCLUSION: The Lyman parameters generated presently and the new form of NTD may be used to predict NTCP for treatment planning of innovative liver irradiation with different fractionations, such as hypofractioned stereotactic body radiation therapy.

Author List

Tai A, Erickson B, Li XA

Authors

Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of Wisconsin
X Allen Li PhD Professor in the Radiation Oncology department at Medical College of Wisconsin
An Tai PhD Associate Professor in the Radiation Oncology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Algorithms
Carcinoma, Hepatocellular
Chi-Square Distribution
Humans
Linear Models
Liver
Liver Neoplasms
Probability
Radiation Injuries
Radiation Tolerance
Tumor Burden
jenkins-FCD Prod-480 9a4deaf152b0b06dd18151814fff2e18f6c05280