Chicago, Ill. -- The ASTRO annual meeting continues in the windy city. While overall attendance is down slightly, you wouldn't know it from the exhibit hall, where a steady crowd is creating strong booth traffic for exhibitors despite a still-lagging economy. A few new radiation oncology technologies made it onto ASTRO's trade show floor this year. TomoTherapy's new TomoHD radiation therapy system is one of those in the limelight.

DOTmed met up with TomoTherapy Communications Manager Kevin O'Malley and Director of Product Strategy Corey Lawson at the TomoTherapy booth to get a good look at the system and to talk about its features.

The TomoHD system comes standard with advanced treatment delivery technologies that are only available as options on TomoTherapy's Hi-Art system, also on the display at ASTRO this year. TomoTherapy's new system comes integrated with several enterprise technologies and upgrades from previously released models.
"On the inside, the TomoHD has over 15 platform enhancements," said O'Malley. "There's a new linear accelerator in the system called the Dragon LINAC and a Hitachi detector. The jaw actuators allow for a works-in-progress advanced delivery technique that will reduce treatment time from 40 to 75 percent."

The jaw actuators comprise the primary collimator, which works in conjunction with TomoTherapy's patented binary collimator with 64 tungsten leaves that shift, in microsecond speeds, to continuously shape the treatment beam into minute beamlets for intensity modulated radiation therapy (IMRT).

TomoTherapy acquired the Dragon LINAC manufacturer, Chengdu twin peak Accelerator Technology, Inc., late last year. TomoHD's LINAC target has three times the life span of other linear accelerator targets, which convert the electron beams into varying energies, and TomoHD's onboard fan-beam CT imaging technology drives the system's image-guided radiation therapy (IGRT) capabilities.

"From an imaging standpoint, we've made more than just speed improvements; we've also made some image quality improvements," said Lawson. "From a speed perspective, we've increased the speed of acquisition on the images by between 60 to 70 percent. Instead of rotating at 6 rpm, we're rotating at 10 rpm and at the same time getting a better quality image."

The treatment beam itself can be modulated in two ways. The TomoHD delivers radiation in either a sweeping, 360-degree continuous beam, dubbed the TomoHelical mode, or in discrete angles with the TomoDirect mode. TomoHelical treatment is ideal for complex tumor volumes and locations, while TomoDirect may be better suited for more superficial tumors, such as in the case of breast cancer tumors.

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