Comparison of Chest Wall and Lymphatic Radiotherapy Techniques in Patients with Left Breast Carcinoma.
OBJECTIVE
The aim of this study was to find the most appropriate technique for postmastectomy chest wall (CW) and lymphatic irradiation.


METHODS
Partially wide tangent, 30/70 photon/electron mix, 20/80 photon/electron mix and CW and internal mammary en face electron field, were studied on computerized tomography (CT) scans of 10 left breast carcinoma patients and dosimetric calculations have been studied. Dose volume histograms (DVH) obtained from treatment planning system (TPS) were used for minimal, maximal and mean doses received by the clinical target volumes and critical structures.


RESULTS
Partially wide tangent field resulted in the most homogeneous dose distribution for the CW and a significantly lower lung and heart doses compared with all other techniques. However, right breast dose was significantly higher for partially wide tangent technique than that each of the other techniques. Approximately 0.6-7.9% differences were found between thermoluminescent dosimeter (TLD) and treatment planning system (TPS). The daily surface doses calculating using Gafchromic® external beam therapy (EBT) dosimetry films were 161.8±2.7 cGy for the naked, 241.0±1.5 cGy when 0.5 cm bolus was used and 255.3±2.7 cGy when 1 cm bolus was used.


CONCLUSIONS
As a result of this study, partially wide tangent field was found to be the most appropriate technique in terms of the dose distribution, treatment planning and set-up procedure. The main disadvantage of this technique was the higher dose to the contralateral breast comparing the other techniques.
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Melis
M
Gültekin
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Mehmet
M
Karabuğa
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Ferah
F
Yıldız
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Gökhan
G
Özyiğit
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Mustafa
M
Cengiz
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Faruk
F
Zorlu
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Fadıl
F
Akyol
Department of Radiation Oncology, Hacettepe University Faculty of Medicine, Ankara, Turkey.
Murat
M
Gürkaynak
Breast cancer; dosimetry; radiation; techniques; treatment