Back to a hospital....

Have you tried calling HR to ask if refreshers would help? I would try that bc hospital may have different requirements/ programs etc. Most hospitals won't hire without "recent" acute experience which could also vary from hospital to hospital. You might also try a new resume bc most hospitals use a program to sift through and you may not be using the correct words/terminology for the computer to pick it up. There are some articles on here about that, one by NurseBeth that was very good. 

As with many industries, it's often who you know not what you know. Do you have any contacts in the hospitals? Any former colleagues that are nurses or techs in a hospital? Sometimes a good word from an employee will bring a potential hire to the attention of the right people. Your resume may not be getting past the recruiters, but if a hiring manager knows you're a viable applicant they can get your resume.

Good luck!