X-ray radiography has attracted considerable attention in various industries and research fields, including digital X-ray detectors, complementary metal-oxide-semiconductor imaging, and disease diagnostic systems. In the field of X-ray detectors, there is a growing demand for the development of high-performance metal oxide thin-film transistor (MOTFT) panels composed of digital X-ray detectors with radiation hardness. Developing radiation-hard devices and integrated circuits is essential for the realization of high-quality X-ray images with high resolution and good stability. Here we investigate the radiation hardness of MOTFTs under X-ray irradiation, with a specific focus on amorphous indium gallium zinc oxide (a-IGZO, In:Ga:Zn = 1:1:1) and amorphous zinc tin oxide (a-ZTO, Zn:Sn = 7:3). The electrical characteristics, chemical structure, and surface morphology of both MOTFTs were analyzed before and after X-ray exposure. We also systematically analyze the radiation-induced damage, considering the occurrence, ionization, and compensation of oxygen vacancies in the MO semiconductor layers. After X-ray irradiation, a-IGZO TFTs exhibit a significant negative shift in their threshold voltage values (ΔV_th ≤ −20 V), whereas a-ZTO TFTs show superior radiation resistance (ΔV_th ≤ −10 V), emphasizing relatively stable electrical characteristics against X-ray irradiation. Further, X-ray photoelectron spectroscopy (XPS) measurement were carried out to determine the radiation damage mechanism in MO semiconductor layers. Deconvolution of the O 1s spectra reveals the contribution of oxygen atoms in M-O-M lattice, oxygen atoms near oxygen vacancies (M-O_vac), and oxygen atoms in hydroxyl groups (M-OH compounds) in a-IGZO and a-ZTO thin-films. Clearly, when X-ray is irradiated, the M-O-M content of the a-ZTO films is larger than that of the a-IGZO films, while the M-O_vac content follows an opposite trend. This result demonstrates that a-ZTO TFTs have notable potential of device stability under X-ray irradiation compared to a-IGZO TFTs. In summary, this study provides valuable insights into the radiation hardness of MOTFT, especially when Sn is incorporated, for robust X-ray imaging applications.