title: Dosimetric comparison between intensity-modulated radiotherapy and standard wedged tangential technique for whole-breast radiotherapy in Asian women with relatively small breast volumes.
abstract: We sought to investigate whether intensity-modulated radiotherapy (IMRT) has a dosimetric advantage compared to the standard wedged tangential technique (SWT) for whole-breast radiotherapy (WBRT) in Asian women with relatively small breast volume. Computed tomography images of 25 Asian patients with early-stage breast cancer (right 15, left 10) used for WBRT planning were examined. After contouring the target volumes and bilateral lungs and, for left-side treatment, the heart, 4 plans were made for each patient: namely, SWT, tangential-field IMRT (T-IMRT), 3-field IMRT (3F-IMRT), and 4-field IMRT (4F-IMRT). The prescribed dose was 5000 cGy. The median planning target volume (PTV) for WBRT was 552.6 cc (range 288.8-1518.4 cc). Compared to SWT, (1) T-IMRT achieved significant improvement for dose homogeneity in the PTV (p < 0.001) and the dose received by 2% (D2) of the PTV (p < 0.001). T-IMRT also reduced the bilateral lung mean dose (p < 0.001) and the ipsilateral lung volume which received more than 20 Gy (V20) (p = 0.01). (2) 3F-IMRT resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). (3) 4F-IMRT also resulted in a significant increase in the mean dose to the ipsilateral lung (p < 0.001) and to the contralateral lung (p < 0.001). Tangential-field IMRT provided an improved dose distribution compared with SWT for WBRT in Asian women with a relatively small breast volume.
authors: Department of Radiation Medicine, Hokkaido University Graduate School of Medicine, North 15 West 7 Kita-ku, Sapporo, 060-8638, Japan.
authors: Kazuhiko
authors: K
authors: Tsuchiya
authors: Rumiko
authors: R
authors: Kinoshita
authors: Shinichi
authors: S
authors: Shimizu
authors: Kentaro
authors: K
authors: Nishioka
authors: Keiichi
authors: K
authors: Harada
authors: Noboru
authors: N
authors: Nishikawa
authors: Ryusuke
authors: R
authors: Suzuki
authors: Hiroki
authors: H
authors: Shirato
mesh_terms: D000465:Algorithms; D044466:Asian People; D001940:Breast / Q000473:pathology*; D001943:Breast Neoplasms / Q000208:ethnology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D007564:Japan; D008168:Lung / Q000528:radiation effects; D008327:Mammography; D011874:Radiometry / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D014057:Tomography, X-Ray Computed
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