Table 6:

Small (collimated), non-uniform field condition: brain-absorbed dose of radiation and excess relative risk of developing brain tumors as a function of patient age

Age, y	MSD, Both Planes, mGy	SD, Both Planes, mGy	Brain Dose–to–MSD Conversion Factor	Brain-Absorbed Dose, mGy	Projected Risk of Developing Brain Tumors (×Baseline)
<1	372.9	361.2	0.14	47.9	2.1
1–2	443.5	434.4	0.11	46.3	2.1
3–7	383.3	398.9	0.09	28.0	1.6
8–12	355.3	341.9	0.05	14.8	1.3
13–17	521.3	529.7	0.03	13.0	1.3
18–21	583.5	729.3	0.03	13.9	1.3
All ages	422.7	440	0.08	18.0	1.4

Note:—Projected risk is calculated as (excess relative risk = 0.023/mGy)+1.

SD indicates standard deviation (inter-patient variability).