Imaging for early stage breast cancer

IGRT with in-room helical kV CT

58 patients - 9 fractions – kV helical CT verifications automatic matching between planning and helical CTs using anatomical information

Action level

Residual error

Margin in mm LAT VERT LONG

Skin mark

-

-

8.6

12.8

12.9

IGRT1

5 mm

0

5.5

4.9

4.8

IGRT2

5 mm 3 mm

5.9

6.8

6.7

IGRT3

3 mm 3 mm

4.9

5.8

5.8

> 1 cm CTV-PTV margins are needed in LONG and VERT directions at skin-mark setup

5-7 mm margins can be applied with CT guidance performed before each fraction