Alpha/Beta Ratio for Normal Lung Tissue as Estimated From Lung Cancer Patients Treated With Stereotactic Body and Conventionally Fractionated Radiation Therapy
| Autor: | A. Scheenstra, Jan-Jakob Sonke, Eugène M.F. Damen, Maddalena Rossi, Joos V. Lebesque, José Belderbos |
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| Rok vydání: | 2014 |
| Předmět: |
Male
Cancer Research Lung Neoplasms Cell Survival medicine.medical_treatment Radiosurgery Carcinoma Non-Small-Cell Lung Forced Expiratory Volume Carcinoma Relative biological effectiveness Humans Medicine Radiology Nuclear Medicine and imaging Radiosensitivity Lung cancer Lung Aged Retrospective Studies Aged 80 and over Radiation business.industry Dose fractionation Middle Aged medicine.disease Radiation therapy Oncology Linear Models Female Dose Fractionation Radiation business Nuclear medicine Perfusion Relative Biological Effectiveness |
| Zdroj: | International Journal of Radiation Oncology*Biology*Physics. 88:224-228 |
| ISSN: | 0360-3016 |
| DOI: | 10.1016/j.ijrobp.2013.10.015 |
| Popis: | Purpose To estimate the α/β ratio for which the dose-dependent lung perfusion reductions for stereotactic body radiation therapy (SBRT) and conventionally fractionated radiation therapy (CFRT) are biologically equivalent. Methods and Materials The relations between local dose and perfusion reduction 4 months after treatment in lung cancer patients treated with SBRT and CFRT were scaled according to the linear-quadratic model using α/β ratios from 0 Gy to ∞ Gy. To test for which α/β ratio both treatments have equal biological effect, a 5-parameter logistic model was optimized for both dose–effect relationships simultaneously. Beside the α/β ratio, the other 4 parameters were d 50 , the steepness parameter k , and 2 parameters ( M SBRT and M CFRT ) representing the maximal perfusion reduction at high doses for SBRT and CFRT, respectively. Results The optimal fitted model resulted in an α/β ratio of 1.3 Gy (0.5-2.1 Gy), M SBRT = 42.6% (40.4%-44.9%), M CFRT = 66.9% (61.6%-72.1%), d 50 = 35.4 Gy (31.5-9.2 Gy), and k = 2.0 (1.7-2.3). Conclusions An equal reduction of lung perfusion in lung cancer was observed in SBRT and CFRT if local doses were converted by the linear-quadratic model with an α/β ratio equal to 1.3 Gy (0.5-2.1 Gy). |
| Databáze: | OpenAIRE |
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