A high-performance direct-conversion CMOS X-ray detector based on screen-printed CsPbBr₃ perovskite films has been developed, achieving ultra-high spatial and temporal resolution for biomedical imaging. The detector, with a pixel size of 83.2 μm and a 72×72 pixel array, demonstrates a mobility-lifetime product of 5.2×10⁻⁴ cm² V⁻¹ and X-ray sensitivity of 1.6×10⁴ μC Gy⁻¹ cm⁻². It can rapidly image samples larger than 5 cm × 10 cm at 300 frames per second. The detector offers high spatial resolution (5.0 lp mm⁻¹) and low radiation dose (260 nGy), enabling high-resolution, large-area, low-dose dynamic biomedical X-ray and CT imaging, as well as non-destructive X-ray testing and security scanning. The detector's performance surpasses traditional indirect-conversion CMOS detectors, particularly in low-dose imaging. The perovskite film was fabricated via screen printing, with a DMF/DMSO ratio of 3/7 and viscosity of 4101 mPa·s. The detector's X-ray response was measured, showing a linear photocurrent response and a sensitivity of 15891 μC Gy⁻¹ cm⁻². The detector also demonstrated stable performance with minimal dark current drift. 2D radiographic and 3D tomographic imaging were successfully performed, with the detector achieving high spatial resolution and low-dose imaging. The study highlights the potential of perovskite CMOS detectors in next-generation X-ray imaging with enhanced spatial resolution, readout speed, and low-dose detection efficiency. The detector is promising for medical imaging applications such as dental and breast imaging. The research was supported by various funding sources, and the authors declare no competing interests.A high-performance direct-conversion CMOS X-ray detector based on screen-printed CsPbBr₃ perovskite films has been developed, achieving ultra-high spatial and temporal resolution for biomedical imaging. The detector, with a pixel size of 83.2 μm and a 72×72 pixel array, demonstrates a mobility-lifetime product of 5.2×10⁻⁴ cm² V⁻¹ and X-ray sensitivity of 1.6×10⁴ μC Gy⁻¹ cm⁻². It can rapidly image samples larger than 5 cm × 10 cm at 300 frames per second. The detector offers high spatial resolution (5.0 lp mm⁻¹) and low radiation dose (260 nGy), enabling high-resolution, large-area, low-dose dynamic biomedical X-ray and CT imaging, as well as non-destructive X-ray testing and security scanning. The detector's performance surpasses traditional indirect-conversion CMOS detectors, particularly in low-dose imaging. The perovskite film was fabricated via screen printing, with a DMF/DMSO ratio of 3/7 and viscosity of 4101 mPa·s. The detector's X-ray response was measured, showing a linear photocurrent response and a sensitivity of 15891 μC Gy⁻¹ cm⁻². The detector also demonstrated stable performance with minimal dark current drift. 2D radiographic and 3D tomographic imaging were successfully performed, with the detector achieving high spatial resolution and low-dose imaging. The study highlights the potential of perovskite CMOS detectors in next-generation X-ray imaging with enhanced spatial resolution, readout speed, and low-dose detection efficiency. The detector is promising for medical imaging applications such as dental and breast imaging. The research was supported by various funding sources, and the authors declare no competing interests.