The window may be transparent to therapeutic wavelengths transmitted to and through {HEAD ~ the window} and to {TAIL ~ the skin} below 
The window may be transparent to therapeutic wavelengths transmitted to and through { HEAD ~ the window } and to { TAIL ~ the skin } below
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH