| الوصف: |
Emel Haciislamoglu,1 Yunus Cinar,2 Mehmet Eren,2 Emine Canyilmaz,1 Fatih Gurcan,3 Lasif Serdar,4 Adnan Yoney1 1Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey; 2Department of Radiation Oncology, Faculty of Medicine, Recep Tayyip Erdogan University, Rize, Turkey; 3Department of Computer Engineering, Faculty of Engineering, Karadeniz Technical University, Trabzon, Turkey; 4Department of Radiation Oncology, Kanuni Research and Education Hospital, Trabzon, TurkeyCorrespondence: Emel HaciislamogluDepartment of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, TurkeyTel +90 462 377 56 01Fax +90 462 325 22 70Email emel.haciislamoglu@ktu.edu.trPurpose: This study aimed to compare the secondary cancer risk (SCR) between the sequential boost (SEQ) technique and simultaneous integrated boost (SIB) technique in intensity-modulated radiotherapy (IMRT) and volumetric-modulated arc therapy (VMAT) in patients with nasopharyngeal carcinoma (NPC) using the concepts of organ equivalent dose (OED) and excess absolute risk (EAR).Patients and Methods: IMRT-SEQ, VMAT-SEQ, IMRT-SIB, and VMAT-SIB plans were created with identical objective functions for five patients with early-stage NPC. Three different planning tumor volumes (PTVs; PTV1, PTV2, and PTV3) were delineated for each patient, and the prescribed doses were 50 Gy, 60 Gy, and 70 Gy (2 Gy/fraction), respectively, for the SEQ technique and 52.8 Gy, 59.4 Gy, and 69.3 Gy (33 fractions), respectively, for the SIB technique.Results: All plans were clinically acceptable. There was no difference in most OED-based SCRs between IMRT and VMAT when the same fractionation scheme was used. Compared with the SEQ technique, the SIB technique in IMRT and VMAT was associated with the lowest OEDs for the oral cavity, pharynx, parotids, and submandibular glands, resulting in SCR reduction. SCR for the parotids was much lower than that for the other assessed organs when the SIB technique was used.Conclusion: Our findings suggest that OED-based SCRs are lower with the SIB technique than with the SEQ technique in IMRT and VMAT in most organs for which SCR was calculated; furthermore, SCR for the parotids is much lower than that for other organs when the SIB technique is used in patients with NPC.Keywords: excess absolute risk, intensity-modulated radiotherapy, organ equivalent dose, secondary cancer risk, volumetric-modulated arc therapy |
PDF full text from Publisher