Oncostat is right on with this one. The definition supplied by the snm (Society of Nuclear Medicine) has this definition:

>>Action taken to prevent further changes to a clinical trial database.

NOTE: Locking of a database is done after review, query resolution, and a determination has been made that the database is ready for analysis<<

It has an excellent Powerpoint presentation that explains trials and terminology in detail. Check it out if you have Powerpoint. Great for reference.

www.snm.org/docs/CTN/.../Language%20of%20Clinical%20Trials.ppt‎