Brain-Specific Relative Biological Effectiveness of Protons Based on Long-term Outcome of Patients With Nasopharyngeal Carcinoma
| Autor: | Annie W. Chan, Jay S. Loeffler, Saveli Goldberg, Ying Sun, Jun Ma, Xiaowu Deng, Barbara C. Fullerton, Judith Adams, Wan L. Huo, Harald Paganetti, Hsiao M. Lu, Jason M. Slater, Ying Y. Zhang |
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| Rok vydání: | 2020 |
| Předmět: |
Adult
Male Cancer Research medicine.medical_treatment 030218 nuclear medicine & medical imaging Temporal lobe 03 medical and health sciences 0302 clinical medicine Relative biological effectiveness medicine Proton Therapy Humans Radiology Nuclear Medicine and imaging Prospective Studies Radiation treatment planning Prospective cohort study Proton therapy Radiation Nasopharyngeal Carcinoma medicine.diagnostic_test business.industry Radiotherapy Planning Computer-Assisted Brain Magnetic resonance imaging Radiotherapy Dosage medicine.disease Radiation therapy Treatment Outcome Oncology Nasopharyngeal carcinoma 030220 oncology & carcinogenesis Female Radiotherapy Intensity-Modulated business Nuclear medicine Monte Carlo Method Relative Biological Effectiveness |
| Zdroj: | International journal of radiation oncology, biology, physics. 110(4) |
| ISSN: | 1879-355X |
| Popis: | Uncertainties in relative biological effectiveness (RBE) constitute a major pitfall of the use of protons in clinics. An RBE value of 1.1, which is based on cell culture and animal models, is currently used in clinical proton planning. The purpose of this study was to determine RBE for temporal lobe radiographic changes using long-term follow-up data from patients with nasopharyngeal carcinoma.Five hundred sixty-six patients with newly diagnosed nasopharyngeal carcinoma received double-scattering proton therapy or intensity modulated radiation therapy at our institutions. The 2 treatment cohorts were well matched. Proton dose distributions were simulated using Monte Carlo and compared with those obtained from the proton clinical treatment planning system. Late treatment effect was defined as development of enhancement of temporal lobe on T1-weighted magnetic resonance imaging, with or without accompanying clinical symptoms. The tolerance dose was calculated with receiving operator characteristic analysis and the Youden index. Tolerance curves, expressed as a cumulative dose-volume histogram, were generated using the cutoff points.With a median follow-up period5 years for both cohorts, 10% of proton patients and 4% of patients undergoing intensity modulated radiation therapy developed temporal lobe enhancement in unilateral temporal lobe. There was no significant difference in dose distributions between the Monte Carlo method and treatment planning system. The tolerance dose-volume levels were V10 (26.1%), V20 (21.9%), V30 (14.0%), V40 (7.7%), V50 (4.8%), and V60 (3.3%) for proton therapy (P.03). Comparison of the two tolerance curves revealed that tolerance doses of proton treatments were lower than that of photon treatments at all dose levels. The dose tolerance at D1% was 58.56 Gy for protons and 69.07 Gy for photons. The RBE for temporal lobe enhancement from proton treatments were calculated to be 1.18.Using long-term clinical outcome of patients with nasopharyngeal carcinoma, our data suggest that the RBE for temporal lobe enhancement is 1.18 at D1%. A prospective study in a large cohort would be necessary to confirm these findings. |
| Databáze: | OpenAIRE |
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