|This article's lead section may not adequately summarize key points of its contents. (July 2013)|
In respiratory physiology, specific ventilation is defined as the ratio of the volume of gas entering a region of the lung (ΔV) following an inspiration, divided by the end-expiratory volume (V0) of that same lung region:
SV = ΔV⁄V0
The distribution of specific ventilation within the lung can be inferred using Multiple Breath Washout (MBW) experiments  or imaging techniques such as Positron Emission Tomography (PET) using 13N, Magnetic Resonance Imaging (MRI) using either hyperpolarized gas (3He, 129Xe) or proton MRI (oxygen enhanced imaging).
- Lewis et al, S. M. Lewis, J. W. Evans, and A. A. Jalowayski. Continuous distributions of specific ventilation recovered from inert gas washout, Journal of Applied Physiology, 1978 vol. 44 no. 3 416-423