As a licensed acupuncturist, I strongly oppose the practice of dry needling by PTs.  This technique is a simplified version of acupuncture that, at its inception, was originally taught to PTs by an acupuncturist.  The similarity for both dry needling and deep acupuncture insertion is that acupuncture needles are deeply placed and strongly stimulated into ashi points/trigger points.  The key as a practitioner is knowing whether or not this technique is appropriate for the patient.  The average licensed acupuncturist has ~2,000 hrs of needle training vs 20-50 hrs for a PT.  I've experienced several patients coming to me with severe pain and worsening of symptoms after dry needling because the strong stimulation wasn't appropriate for them.  I strongly recommend acupuncture needles be used solely by licensed acupuncturists.