Sergery

As I reviewed the results, I noticed that I get each duplicate record twice,
example:

MedRec1    medrec2     PatientID1    PatientID2
000105243  105243      1172214       1090258
... more data
105243     000105243   1090258       1172214

Is there anyway to filter on distinct on this query?

SELECT t1.mpinumber AS MedRecNo1, t2.mpinumber AS MedRecNo2,
		t1.PatientID AS PatientID1, t2.PatientID AS PatientID2,
		t1.Lastname as LastName1, t2.LastName as LastName2
	FROM Patients t1 
		JOIN Patients t2 ON CAST(t1.mpinumber AS int) = CAST(t2.mpinumber AS int)
			AND t1.mpinumber <> t2.mpinumber
order by t1.mpinumber

Thanks again