Using the Microsoft Kinect for Patient Size Estimation and Radiation Dose Normalization: Proof of Concept and Initial Validation

Monitoring patients' imaging-related radiation is currently a hot topic, but there are many obstacles to accurate, patient-specific dose estimation. While some, such as easier access to dose data and parameters, have been overcome, the challenge remains as to how accurately these dose estimates reflect the actual dose received by the patient. The main parameter that is often not considered is patient size. There are many surrogates—weight, body mass index, effective diameter—but none of these truly reflect the three-dimensional “size” of an individual. In this work, we present and evaluate a novel approach to estimating patient volume using the Microsoft Kinect™, a combination RGB camera-infrared depth sensor device. The goal of using this device is to generate a three-dimensional estimate of patient size, in order to more effectively model the dimensions of the anatomy of interest and not only enable better normalization of dose estimates but also promote more patient-specific protocoling of future CT examinations. Preliminary testing and validation of this system reveals good correlation when individuals are standing upright with their arms by their sides, but demonstrates some variation with arm position. Further evaluation and testing is necessary with multiple patient positions and in both adult and pediatric patients. Correlation with other patient size metrics will also be helpful, as the ideal measure of patient “size” may in fact be a combination of existing metrics and newly developed techniques.