This was a Special Health Board established in 2000, and as far as I can tell, rolled into the Health Technology Board for Scotland–HTBS, which in turn has also been shuttered
Medical » British Medicine
Scottish Health Technology Assessment Centre
SHSO - SHSS - SHSZ - SHT - SHTA - SHTC - SHTF - SHTG - SHTHND - SHTML
"SHTAC." Abbreviations.com. STANDS4 LLC, 2015. Web. 1 Dec. 2015. <http://www.abbreviations.com/SHTAC>.