The ANRAD Corporation is the world leader in terms of types of Direct Conversion flat panel x-ray detectors based on a-Se. To date, 5 panels are available:

SMAM: 17 X 24 cm flat-panel for digital mammography
LMAM: 24 X 30 cm flat-panel for digital mammography
GR17: 43 X 43 cm flat-panel for general radiography
FPD9: 23 X 23 cm flat-panel for real-time applications
FPD14: 35 X 35 cm flat-panel for real-time applications