Dosimetric comparison of left-sided whole-breast irradiation with 3DCRT, forward-planned IMRT, inverse-planned IMRT, helical tomotherapy, and volumetric arc therapy.
OBJECTIVE
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.


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.


CONCLUSIONS
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.
Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: emel.haciislamoglu@ktu.edu.tr.
Emel
E
Haciislamoglu
Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: colak.fatma@gmail.com.
Fatma
F
Colak
Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: dremocan@yahoo.com.
Emine
E
Canyilmaz
Department of Radiation Oncology, Faculty of Medicine, Gülhane Military Medical Academy, Ankara, Turkey. Electronic address: diricanbahar@gmail.com.
Bahar
B
Dirican
Neolife Medical Centre, İstanbul, Turkey. Electronic address: sgurdall@yahoo.com.
Salih
S
Gurdalli
Department of Nuclear Physics, Faculty of Science, Karadeniz Technical University, Trabzon, Turkey. Electronic address: hakany@ktu.edu.tr.
Ahmet Hakan
AH
Yilmaz
Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: adnan.yoney@gmail.com.
Adnan
A
Yoney
Department of Radiation Oncology, Faculty of Medicine, Karadeniz Technical University, Trabzon, Turkey. Electronic address: zbahat@hotmail.com.
Zumrut
Z
Bahat
D001940:Breast / Q000528:radiation effects*; D001943:Breast Neoplasms / Q000532:radiotherapy; D006801:Humans; D058958:Organs at Risk / Q000528:radiation effects; D011874:Radiometry; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects / Q000379:methods*
Breast cancer; Contralateral breast; Helical tomotherapy; Intensity modulated radiotherapy; Volumetric arc therapy