Table 3. Mean organ doses from our helical tomotherapy plans for prone-positioned patients compared with the results reported by Goddu et al [16] for helical tomotherapy plans to treat the left breast and regional lymph nodes to 50.4 Gy for supine-positioned patients.

OAR structure	Treated side	Mean organ dose (Gy), prone plans (current study)		Mean organ dose (Gy), supine plans ([16]) scaled to 45 Gy radiation dose
		μ±σ	Range	μ±σ	Range
Ipsilateral lung	Left	10.0±3.0	6.6–14.4	10.6±1.3	8.6–13.2
	Right	8.8±2.2	5.5–11.7
Contralateral lung	Left	3.8±0.6	2.8–4.3	3.8±0.9	1.9–5.1
	Right	2.8±0.8	1.6–3.9
Contralateral breast	Left	2.4±1.0	1.0–3.4	3.8±0.6	2.8–4.6
	Right	2.3±1.0	0.6–3.3
Heart	Left	8.7±1.3	6.8–10.1	10.9±1.6	8.8–13.8
	Right	2.7±1.0	0.6–3.3

μ, average; σ, standard deviation; OAR, organ at risk.

The tabulated values were scaled down by a factor of (45 Gy)/(50.4 Gy).