Dosimetric comparison of left-sided whole breast irradiation with 3DCRT, forward-planned IMRT, inverse-planned IMRT, helical tomotherapy, and topotherapy

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• 作者：Leah K. Schubert^a ; ^{lkschubert@unmc.edu} ; Vinai Gondi^b ; Evan Sengbusch^c ; David C. Westerly^d ; Emilie T. Soisson^e ; Bhudatt R. Paliwal^b ; ^c ; Thomas Rockwell Mackie^b ; ^c ; ^f ; Minesh P. Mehta^b ; Rakesh R. Patel^b ; ^g ; Wolfgang A. Tomé ; ^b ; ^c ; George M. Cannon^b
• 关键词：Breast cancer ; Tomotherapy ; Topotherapy ; Tangents ; IMRT
• 刊名：Radiotherapy and Oncology
• 出版年：2011
• 出版时间：August, 2011
• 年：2011
• 卷：100
• 期：2
• 页码：241-246
• 全文大小：1K

文摘

Background and purpose

To compare left-sided whole breast conventional and intensity-modulated radiotherapy (IMRT) treatment planning techniques.

Materials and methods

Treatment plans were created for 10 consecutive patients. Three-dimensional conformal radiotherapy (3DCRT), forward-planned IMRT (for-IMRT), and inverse-planned IMRT (inv-IMRT) used two tangent beams. For-IMRT utilized up to four segments per beam. For helical tomotherapy (HT) plans, beamlet entrance and/or exit to critical structures was blocked. Topotherapy plans, which used static gantry angles with simultaneous couch translation and inverse-planned intensity modulation, used two tangent beams. Plans were normalized to 50 Gy to 95 % of the retracted PTV.

Results

Target max doses were reduced with for-IMRT compared to 3DCRT, which were further reduced with HT, topotherapy, and inv-IMRT. HT resulted in lowest heart and ipsilateral lung max doses, but had higher mean doses. Inv-IMRT and topotherapy reduced ipsilateral lung mean and max doses compared to 3DCRT and for-IMRT.

Conclusions

All modalities evaluated provide adequate coverage of the intact breast. HT, topotherapy, and inv-IMRT can reduce high doses to the target and normal tissues, although HT results in increased low doses to large volume of normal tissue. For-IMRT improves target homogeneity compared with 3DCRT, but to a lesser degree than the inverse-planned modalities.