Suggested dose adjustments by Nidus Volume in cc
Volume Dose (Pitt) Volume Dose (others)
< 4cc 23-24Gy <2cc 24Gy
4 - 14cc 20Gy 2.1 - 5cc 22-23Gy
> 14cc 16Gy 5 - 8cc 21Gy
    8 - 13.5cc 18Gy
 
As noted it takes about  22-24Gy(marginal dose i.e. 50% IDL) to reliably obliterate the nidus. (If the mass is in a sensitive site i.e. brainstem the dose may limited to 18Gy. The AVM (Pitt) data used 12Gy volume to predict toxicity and volumes up to 20cc had a low risk (< 10%) except brain stem sites (motor strip does not require dose adjustments.)

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Obliteration Rate by Marginal  Dose in non-embolized patients from U Pitt
Marginal Dose Obliterated
12Gy 23 - 27%
14Gy 44-49%
16Gy 60-66%
18Gy 72-77%
20Gy 80-82%
22Gy 84%
23Gy 85-86%
24Gy 85-86%
26Gy 85-87%

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