Portable chest radiography is the most commonly ordered radiographic test in the intensive care unit (ICU). In the ICU, a succession of portable images is usually taken over a period of time to monitor the progress of a patient’s condition. A prompt diagnosis of any changes in the conditions of these ICU patients allows clinicians to provide immediate attention and treatments that are required to prevent the conditions from worsening and which could result in a treat to the patient’s life. However, because of differences in X-ray exposure setting, patient and apparatus positioning, scattering, and grid application, for example, differences in image quality from on image to the next taken at different times can be significant. The differences in image quality make it difficult for clinicians to compare images to detect subtle changes. This paper presents an image-rendering method that reduces the variability in image appearance and enhances the diagnostic quality of these images. Use of the presented method allows clinicians to detect subtle pathological changes from one image to the next, thus improving the quality of patient management in the ICU.