This chapter presents a technical evaluation of some of the more popular models of test objects and phantoms commonly applied to image quality and/or radiation dose evaluation in different X-ray imaging modalities. It explores phantoms in terms of the imaging modality of application, and image quality and dose assessment phantoms will be covered for each modality. The design and characteristics of a phantom for medical imaging are selected by functional and/or anatomical characteristics of the body or the specific organ that it should simulate and also by the purpose of its application. The phantoms used for image quality in general radiology are typically composed of tissue-equivalent material that mimics human tissue in terms of attenuation, and scattering of X-rays. The commercially available phantoms have been developed for quality control testing of conventional X-ray systems in subjective and quantitative ways. Anthropomorphic phantoms are very useful for monitoring, training, and optimizing exposure parameters prior to clinical studies and implementation of initial protocols.