How to Convert PDF to Multi-page TIFF in VB.NET?

Imports PQScan.PDFToImage

Namespace PDF2TIFF
  Class Program
    Private Shared Sub Main(args As String())
      ' Create an instance of PQScan.PDFToImage.PDFDocument object.
      Dim pdfDoc As New PDFDocument()

      ' Load PDF document.
      pdfDoc.LoadPDF("sample.pdf")

      ' Save multi-page tiff
      pdfDoc.ToMultiPageTiff("multipage.tiff")
    End Sub
  End Class
End Namespace