T-SQL (SS2K8) :: Appropriate Query For Multi Parameters?

I am using the following code in my query to fetch data for my ssrs report which have a parameter @auditCode, where multiple auditCodes can be inputted to generate the report.

Is there any other way I can achieve the same functionality avoiding the part charindex(LU.auditCode,@auditCode)<>0 , as it will return wrong results.

For instance, it will return, the results for the audit code ‘INPS45’ and ‘INPS450000’ when audit code ‘INPS45’ is inputted.

SELECT distinct Ac.activityCode,
Ac.ActivityName + isnull(Ac.description,'') AS ActivityName,
Ac.activityStartDate, Ac.activityEndDate,
LU.auditCode,
LU.AuditName,
St.studyCode AS StudyCode,
St.StudyName AS StudyName

[Code] ....