Fig. 1.

Equivalent dose per treatment dose (mSv Gy⁻¹) as a function of lateral distance to the field. Light grey area: Range of measured (Yan et al. 2002; Mesoloras et al. 2006; Wroe et al. 2007, 2009; Moyers et al. 2008; Yonai et al. 2008; Clasie et al. 2010) and simulated (Polf and Newhauser 2005; Zheng et al. 2007; Moyers et al. 2008; Zacharatou Jarlskog et al. 2008; Clasie et al. 2010) data for a variety of proton beam configurations using passive scattered beam delivery. Dark grey area: Results for scanned proton beams (Schneider et al. 2002; Clasie et al. 2010). Also shown for comparison is the scattered photon dose equivalent for a randomly chosen 10×10 cm² intensity-modulated photon field using a 6 MV beam (dotted line) (Klein et al. 2006).