Emel Haciislamoglu1, Fatma Colak2, Emine Canyilmaz3, Bahar Dirican4, Salih Gurdalli5, Ahmet Hakan Yilmaz6, Adnan Yoney7, Zumrut Bahat8. 1. Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: emel.haciislamoglu@ktu.edu.tr. 2. Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: colak.fatma@gmail.com. 3. Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: dremocan@yahoo.com. 4. Department of Radiation Oncology, Faculty of Medicine, Gülhane Military Medical Academy, Ankara, Turkey. Electronic address: diricanbahar@gmail.com. 5. Neolife Medical Centre, İstanbul, Turkey. Electronic address: sgurdall@yahoo.com. 6. Department of Nuclear Physics, Faculty of Science, Karadeniz Technical University, Trabzon, Turkey. Electronic address: hakany@ktu.edu.tr. 7. Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: adnan.yoney@gmail.com. 8. Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: zbahat@hotmail.com.
Abstract
PURPOSE: This study evaluated the dose distribution and homogeneity of four different types of intensity-modulated radiotherapy (IMRT) in comparison with standard wedged tangential-beam three-dimensional conformal radiotherapy (3DCRT) of the left breast in patients who had undergone lumpectomy. MATERIALS AND METHODS: Five radiotherapy treatment plans, including 3DCRT, forward-planned IMRT (for-IMRT), inverse IMRT (inv-IMRT), helical tomotherapy (HT) and volumetric-modulated arc therapy (VMAT), were created for 15 consecutive patients. RESULTS: All modalities presented similar target coverage. Target max doses were reduced with for-IMRT compared to 3DCRT, and these doses were further reduced with inv-IMRT and HT. HT resulted in the lowest max doses delivered to the heart, left anterior descending artery (LAD), and ipsilateral lung, but had higher mean, max, and low doses delivered to contralateral breast. HT resulted in increased low doses to a large volume of healthy tissue. Compared to other techniques, all inverse-planned modalities significantly improved conformity number; however, VMAT had worse homogeneity. The for-IMRT plan significantly lowered monitor unit (MU) compared to the inverse-planned techniques. CONCLUSION: All modalities evaluated provide adequate coverage of the whole breast. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned inv-IMRT and HT. HT decreases the ipsilateral OAR volumes receiving higher and mean doses with an increase in the volumes receiving low doses, which is known to lead to an increased rate of radiation-induced secondary malignancies.
PURPOSE: This study evaluated the dose distribution and homogeneity of four different types of intensity-modulated radiotherapy (IMRT) in comparison with standard wedged tangential-beam three-dimensional conformal radiotherapy (3DCRT) of the left breast in patients who had undergone lumpectomy. MATERIALS AND METHODS: Five radiotherapy treatment plans, including 3DCRT, forward-planned IMRT (for-IMRT), inverse IMRT (inv-IMRT), helical tomotherapy (HT) and volumetric-modulated arc therapy (VMAT), were created for 15 consecutive patients. RESULTS: All modalities presented similar target coverage. Target max doses were reduced with for-IMRT compared to 3DCRT, and these doses were further reduced with inv-IMRT and HT. HT resulted in the lowest max doses delivered to the heart, left anterior descending artery (LAD), and ipsilateral lung, but had higher mean, max, and low doses delivered to contralateral breast. HT resulted in increased low doses to a large volume of healthy tissue. Compared to other techniques, all inverse-planned modalities significantly improved conformity number; however, VMAT had worse homogeneity. The for-IMRT plan significantly lowered monitor unit (MU) compared to the inverse-planned techniques. CONCLUSION: All modalities evaluated provide adequate coverage of the whole breast. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned inv-IMRT and HT. HT decreases the ipsilateral OAR volumes receiving higher and mean doses with an increase in the volumes receiving low doses, which is known to lead to an increased rate of radiation-induced secondary malignancies.
Authors: M N Duma; C Heinrich; C Schönknecht; B Chizzali; M Mayinger; M Devecka; S Kampfer; S E Combs Journal: Radiat Oncol Date: 2017-01-28 Impact factor: 3.481