Table 5:

Large (uncollimated), uniform field condition: brain absorbed dose of radiation and 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	0.48	164.4	4.8
1–2	443.5	434.4	0.38	160.0	4.7
3–7	383.3	398.9	0.30	93.3	3.2
8–12	355.3	341.9	0.25	74.1	2.7
13–17	521.3	529.7	0.24	103.9	3.4
18–21	583.5	729.3	0.23	106.3	3.4
All ages	422.7	440	0.25	90.1	3.1

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

SD indicates standard deviation (inter-patient variability).