Design of a novel DXA scanner with a CdTe photon-counting Timepix4 detector for peripheral bone densitometry

AbstraktAbstract

Bone densitometry in osteoporosis diagnosis via dual-energy X-ray absorptiometry (DXA) can benefit from advances in imaging detector technology. We devised a com-pact imaging scanner – DXA4A – using a photon counting and energy-sensitive Timepix4 hybrid pixel detector (512 x 448 pixels, 55 µm pitch), for areal bone mineral density (aBMD) assessments in the distal radius and tibia in the clinic and for future in-flight astronauts’ bone health assessment. We present the design and initial tests of the scanner. A Timepix4 detector with a 1-mm-thick CdTe sensor was tested in the la-boratory with X-ray tube sources, acquiring first images of test samples. Monte Carlo simulations were implemented for scanner design and performance prediction, using 50 kVp unfiltered and 100 kVp Sm K-edge filtered spectra. With a digital twin of the scanner and patient wrist we set-up a virtual imaging study and determined the aBMD in the forearm of a patient (0.515 ± 0.048 g/cm2), in agreement with the clinical DXA value (0.571 g/cm2 for the total forearm). This study highlights the feasibility of realiz-ing a compact DXA scanner for distal tibia and radius with spectral capabilities, ex-ploiting Timepix4 hybrid detectors for its peculiar energy sensitivity and photon event timing properties for tissue identification.

Bone densitometry in osteoporosis diagnosis via dual-energy X-ray absorptiometry (DXA) can benefit from advances in imaging detector technology. We devised a com-pact imaging scanner – DXA4A – using a photon counting and energy-sensitive Timepix4 hybrid pixel detector (512 x 448 pixels, 55 µm pitch), for areal bone mineral density (aBMD) assessments in the distal radius and tibia in the clinic and for future in-flight astronauts’ bone health assessment. We present the design and initial tests of the scanner. A Timepix4 detector with a 1-mm-thick CdTe sensor was tested in the la-boratory with X-ray tube sources, acquiring first images of test samples. Monte Carlo simulations were implemented for scanner design and performance prediction, using 50 kVp unfiltered and 100 kVp Sm K-edge filtered spectra. With a digital twin of the scanner and patient wrist we set-up a virtual imaging study and determined the aBMD in the forearm of a patient (0.515 ± 0.048 g/cm2), in agreement with the clinical DXA value (0.571 g/cm2 for the total forearm). This study highlights the feasibility of realiz-ing a compact DXA scanner for distal tibia and radius with spectral capabilities, ex-ploiting Timepix4 hybrid detectors for its peculiar energy sensitivity and photon event timing properties for tissue identification.