This is a consolidated look at the applications of various deep learning techniques in the field of radiology. For the past few years, deep learning has pervaded every field and the deep learning revolution has opened up new frontiers in artificial intelligence. From healthcare to art or from education to business-it has been applied successfully in a range of different domains to attain state-of-the-art, often reporting near human-level performance. Hence, in the field of radiology too, especially for image interpretation tasks, deep learning techniques are being increasingly used in recent times to optimize the medical workflow and to achieve better patient care and efficient medical surveillance. Convolutional neural networks (CNNs) are mostly dominant in the case of image interpretation applications in radiology, because of their unprecedented success in image-related applications in other domains such as computer vision. However, other deep learning techniques like recurrent neural networks (RNNs) and generative adversarial networks (GANs) are also being used in recent research for various image-related tasks in radiology like classification, segmentation and detection. In this paper, the imaging modalities associated with this field and the application of different deep learning techniques to these have been discussed at length. Moreover, deep learning can also be applied to radiology use cases other than image interpretation, such as patient scheduling or the processing of free-text radiology reports to improve healthcare surveillance. Finally, in this study, the practical challenges as well as the future research directions of this domain have been discussed. Some challenges include dearth of annotated data, the fear of AI unseating radiologist professionals, legal and ethical issues, black box behaviour of neural networks and adversarial fooling of deep learning algorithms by reverse engineering. To counter some of these problems, a few trends in applying deep learning to radiology in the future may include improved visualisation techniques, integration of the entire workflow for practical usability, unsupervised methods of deep learning like auto-encoders and improving research on GANs in radiology. This study may prove useful for researchers applying deep learning to various radiology use cases by providing a detailed overview of the state-of-theart research in the field.