Accuracy

It’s not just about pretty pictures. In IGRT, it’s what you can do with—and expect from—the images you acquire that matter most. That’s why we designed the Hi·Art® treatment system to integrate CTrue™, the only imaging technology that can be used for every patient’s treatment, every day.

CTrue logo CT technology has long been a primary tool in the diagnosis of cancer, as well as in the delineation of targets/organs-at-risk and the generation of a patient’s treatment plan. With the Hi·Art treatment system, the role of CT is extended even further—in the most natural way. We call it CTrue imaging, and it’s exactly what is needed for true image guidance and adaptive planning to be practiced today.

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Overlay ROIs
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Dose-guided radiation therapy

For patient set-up and positioning, CTrue images play a critical role. With every treatment fraction, you can choose to see where the anatomy is, compared to where it’s supposed to be, based on accurate, consistent 3D image pixel locations relative to the treatment beam. Then, with automated image registration, you can quickly determine any required adjustment, precisely apply a couch offset—and treat.

Like your diagnostic CT scanner or CT Simulator, daily CT images from the Hi·Art treatment system are acquired helically using a fan-beam with a conventional CT detector mounted on a ring gantry. Fan-beam CT images have significantly less scatter than CT images acquired using a cone beam with a flat panel detector. The result is pixel values that can be accurately and consistently converted to density maps, just like a diagnostic CT scanner. This means CTrue images are valuable for more than just guiding patient positioning.

With the added advantage of an MV beam, CTrue images yield accurate CT numbers regardless of patient size and shape, and even in the presence of high atomic number materials. Furthermore, imaging dose is consistently low (1-3 cGy, depending on slice thickness). With these attributes, the images are not only consistent in quality, but are usable for accurate, heterogeneous dose calculation*. This opens the door to dose reconstruction and adaptive planning capabilities.

*The use of megavoltage CT (MVCT) images for dose recomputations, K. Langen, et al, Phys. Med. Biol. 50 (2005) 4259–4276. See more Selected Publications.