Single-Shot Quantitative X-ray Imaging for Interventional Procedures - Project Abstract
Primary liver cancer, and specifically hepatocellular carcinoma (HCC), is the third most common cause of
cancer death worldwide. In patients with intermediate-stage or unresectable HCC, transarterial
chemoembolization (TACE) is the most widely used therapy. The success of TACE critically depends on the
accurate and complete targeting of the tumor. While x-ray image guidance is routinely used to qualitatively
visualize the drug delivery, it currently does not enable quantitative guidance and assessment to determine
appropriate delivery endpoints. Therefore, TACE endpoints are highly variable across operators and patients,
with poor ability to predict tumor response and patient outcome.
To accurately monitor drug accumulation in the tumor, real-time quantification of radiopaque iodine (mixed
with the drug prior to delivery) is needed with every x-ray image, a concept we entitle single-shot quantitative
imaging (SSQI). SSQI is not currently possible due to several challenges with x-ray imaging, including scatter,
multiple overlaying materials, and patient and system motion. We therefore propose robust SSQI enabled by the
combination of a primary modulator and a dual-layer detector to quantify iodine areal density in real time. The
primary modulator provides scatter correction, while the dual-layer detector provides material-specific images
with each exposure. The resulting SSQI system provides iodine quantification and dose-efficient grayscale
images that are robust against motion. A key strength of the proposed solution is its simplicity in hardware and
software – it is compatible with existing system designs, without introducing new complexities or challenges.
Our specific aims include: 1) Build a prototype SSQI system. We will design and construct a primary
modulator with optimized material, pitch, and thickness, as well as a dual-layer detector with optimized scintillator
thicknesses and filter for quantifying iodine in abdominal imaging. We will also develop a real-time image
processing pipeline to convert the modulated dual-layer images into quantitative images. 2) Assess the
quantitative imaging accuracy of prototype SSQI system. We will evaluate the material quantification
accuracy for iodine tasks representative of TACE using phantoms of various sizes with known amounts of iodine,
bone, and other tissue-equivalent materials. We hypothesize that SSQI can achieve accurate iodine
quantification and grayscale accuracy, while being dose efficient.
The proposed studies will establish a new x-ray imaging paradigm that brings quantitation to every image
by simultaneously overcoming several current limitations of x-ray imaging while retaining traditional advantages
such as high spatial and temporal resolution and large-area imaging. The simplicity and broad applicability of
SSQI to x-ray systems has the potential for widespread adoption as a platform for quantitative imaging.
