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 threedimensional "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 camerainfrared 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.

Purpose: Imaging centers are increasingly seeking means to track radiation dose from computed tomography (CT). Many of these methods are based on the dose‐length product (DLP) reported on image‐based dose sheets, such as RADIANCE, an open‐source dose extraction software. We compare dose estimates from RADIANCE to those computed by eXposure, a commercial product which computes organ doses using Monte‐Carlo simulations. Methods: We review dose estimates for 1936 single‐phase, unenhanced head CT examinations performed in 2010 at our institution. The estimated whole‐body effective dose (ED) is derived from the total study DLP by multiplying the ICRP 60‐based k factor of 0.0021. For the same set of studies, ED is derived from the organ doses computed via Monte‐Carlo simulations using MIRD Adult and Age 15 phantom, average scanner model and ICRP 60 tissue weighting factors. ED estimates from both methods are compared. Results: The average ED derived from total DLP is 1.84 +/− 0.44 mSv, while the average ED derived from the organ doses is 2.01 +/− 0.3 mSv. ED estimates derived from the organ doses were 1.91 +/− 0.28 mSv for male patients and 2.11 +/− 0.29 mSv for female patients. According to the literature, adult female heads are 10% smaller on average than adult male heads. We hypothesize that the 11% higher ED estimate in the female patients reflects this head size differential between genders. A common adult head phantom is used for head CT acquisitions, and higher dose estimates in adult females may reflect a longer‐than‐necessary scan length. Conclusions: Estimating whole‐body effective dose using DLP is practical in the current clinical setting. For head CT exams, DLP‐based ED estimates appear concordant with organ dose‐based estimates. The data additionally suggests that dose savings may be achieved by optimizing scan length and mA for female patients.