How to filter system query from DMV ?

Hi:

I want find many information about T-SQL " User Query " from DMV, but it also return SQL Server System Query.

How Can I remove the System Query ?  This is my sample code

SELECT TOP 50
    TextData           = qt.text
    ,DiskReads          = qs.total_physical_reads   -- The worst reads, disk reads
    ,MemoryReads        = qs.total_logical_reads    --Logical Reads are memory reads
    ,Executions         = qs.execution_count
    ,TotalCPUTime       = qs.total_worker_time
    ,AverageCPUTime     = qs.total_worker_time/qs.execution_count
    ,DiskWaitAndCPUTime = qs.total_elapsed_time
    ,MemoryWrites       = qs.max_logical_writes
    ,DateCached         = qs.creation_time
    ,DatabaseName       = DB_Name(qt.dbid)
    ,LastExecutionTime  = qs.last_execution_time
 FROM sys.dm_exec_query_stats AS qs
 CROSS APPLY sys.dm_exec_sql_text(qs.sql_handle) AS qt
 ORDER BY qs.total_worker_time DESC

my407sw