How much brain is destroyed?

In anterior cingulotomy, one of the most commonly used psychosurgical operations nowadays (used in recent years in for example the USA, Canada, Scotland, South Korea, Russia, France, Poland, and Australia), the aim is to "produce lesions of approximately 1x1x2 cm within the anterior cingulate cortex of each hemisphere (ie total lesion volume = ~ 4cc)"

(A magnetic resonance imaging study of regional cortical volumes following stereo tactic anterior cingulotomy, S L Rauch et al. CNS Spectrums 2001 6(3) 214-222)