Help with out-of-range value

Question

I have this query that is giving me an error

The conversion of a varchar data type to a datetime data type resulted in an out-of-range value.

Query:

select 
    COUNT(*) 
from 
    dbo.patient
INNER JOIN 
    dbo.study on dbo.patient.pk = dbo.study.patient_fk
              and dbo.study.study_datetime IS NOT NULL
              and dbo.patient.pat_birthdate IS NOT NULL
              and dbo.study.study_datetime <= DATEADD(D, -2192, GETDATE())
              and dbo.patient.pat_birthdate <= DATEADD(D, -7670, GETDATE());

I read where this might help to be converted to 'DATETIME2', but I can't quite figure out how to correctly convert the column 's.study_datetime' as this column more than likely has some bad values as entries.