Applied Radiology

Options in technology from major manufacturers are expanding the capabilities of lower-end scanners, reducing the compromises that users make when they buy equipment on a budget. For example, Aspire Continuous ImagingTM (CI) technologies, which enable radiologists to view an x-ray computed tomography (CT) study as it's acquired, are now available on the Xpress and Xvision Series CT scanners from Toshiba America Medical Systems, Inc. (Tustin, CA). "As new, more efficient technologies become available, we intend to offer options and upgrades," said Charles Corogenes, director of the CT Business Unit at Toshiba.

Aspire CI includes SureStart, a technology that allows scanning to be delayed until the contrast agent arrives at the region of interest. According to Toshiba, this capability results in high-quality images with up to 25% less contrast, a significant potential cost savings.

Moving interventional procedures from surgery to radiology

"We believe this technology will move many of the guided interventional procedures from the operating room into the radiology department because they can be performed more quickly, less invasively and, therefore, at lower cost," said Mr. Corogenes. (Several of the CT technologies mentioned in this column could become valuable tools for interventional applications, which will be covered in more detail in the July 1998 Applied Radiology, a special focus issue on interventional radiology.)

Toshiba also has new CT technologies that are works-in-progress, including a movable CT gantry for use in a surgical CT system, and an upright CT-both capable of helical scanning, according to the company.

In the surgical CT, the self-propelled gantry travels in the axial direction so it can be used with a standard surgical table in an operating room or other specialized location. "This system could be particularly beneficial in the emergency room when you need to obtain a high-grade scan quickly and then move the scanner out of the way," said Mr. Corogenes.

The upright CT, with the gantry suspended from the ceiling, is built horizontally to facilitate localization of tumors that will be treated with heavy-ion radiation beams. "The ion accelerator beams are horizontal, and the patient is treated in the sitting position," said Mr. Corogenes, adding that the CT device provides for more accurate treatment planning and delivery.

Suite of CT options

Picker International (Cleveland) recently introduced a group of options, called VenueTM, for x-ray computed tomography. Venue is designed to expand the CT suite beyond diagnostics to include intervention.

One option with Venue is FACTSTM (fluoro-assisted computed tomography), a c-arm fluoroscopy x-ray unit that allows minimally invasive imaging procedures to be performed in the CT suite. This ability adds convenience and saves time by eliminating the need to transport patients to a separate room to perform an invasive diagnostic procedure.

According to Picker, FACTS was the only solid-state fluoroscopy system available when it was introduced at the 1997 Radiological Society of North America (RSNA) meeting. It includes an integrated flat-panel detector, which can be positioned between the CT gantry and patient couch, that uses a new amorphous silicon flat-panel photodiode array. The array is "light and compact," according to the company, unlike other c-arm fluoroscopy systems that contain large, heavy intensifier tubes that may be awkward to position.

Another option with Picker's Venue, C-ViewTM, is a new c-arm rail-mounted on the ceiling for positioning on either side of the CT scanner (figure 1). The "slide back" couch can be used for routine CT imaging or can be pulled back for angiography studies.

C-View features a high resolution digital imaging system, according to Picker, with real-time edge enhancement, digital spot capability, road-mapping, and multi-image display.

Digital x-ray detectors

Also at the 1997 RSNA, GE Medical Systems (Milwaukee) announced an agreement with EG&G, Inc., to manufacture a "first-of-its-kind, multi-purpose" digital x-ray detector. The new system replaces conventional x-ray film and chemicals with computer images that can be stored and sent electronically. There also is a potential use for computer-aided detection of abnormalities with these digital x-ray images.

The new detector will form the basis of a new family of GE x-ray products, complemented by networking and archiving options. "The digital detector is the product of one of GE's biggest and most long-range R&D efforts ever. Its 10-year, $100-million development has involved more than 100 scientists and engineers and has resulted in nearly 80 patents," said Lewis S. Edelheit, senior vice president for Corporate R&D at GE.

"This technology gives us the unique ability to make full-sized detectors in one piece, which differs significantly from other approaches that combine several smaller detectors to make a large one," said Mr. Edelheit. "Detectors based on GE's large-area technology will serve the whole spectrum of x-ray applications, from mammography and radiography to real-time fluoroscopy and angiography," he added.

The digital x-ray detector currently is undergoing clinical investigation at mammography and radiology sites, including Massachusetts General Hospital, the hospitals of the University of Massachusetts and University of Colorado, and the Hospital of the University of Pennsylvania. "In preliminary trials, the prototype digital mammography system is producing quality images with all the benefits of digital imaging," said Dr. Daniel Kopans, director of the Breast Imaging Division at Massachusetts General Hospital.

Faster CT scanning, thinner slices

GE also introduced two technologic advances that result in faster CT scanning and thinner slices. With SubSecond Scanning for the ProSpeedTM CT scanner, users can obtain greater helical coverage per breath-hold or 20% shorter scans, according to GE.

With SmartHelicalTM for the HiSpeedTM CT/i scanner, users can reduce the dose of contrast medium by 33%, according to the company. SmartHelical also reduces mA, allowing users to perform longer helical runs with thinner slices. According to GE, physicians can obtain 3-mm slices in the same amount of time required for 5-mm slices with standard helical scanning. "A standard helical scan that might be done at 300 mA for 30 seconds could be done with SmartHelical at 200 mA for 75 seconds, a 150% increase in helical coverage," explained GE.

C-arm systems with isocentric design

Siemens Medical Systems, Inc. (Iselin, NJ) now offers three c-arm systems featuring isocentric design. Isocentricity means that the c-arm's location does not require readjustment when the rotational projection angle is changed, explained Siemens, which can reduce patient and operator x-ray exposure and save examination time.

The SIREMOBIL® Iso-C is designed for a broad range of operating room applications. The POWERMOBILTM series features a 20-kW generator and high frame-rate pulsed fluoroscopy for such procedures as coronary angiography and minimally invasive cardiosurgical interventions. The ARCOSKOP® is designed for trauma and emergency room applications.

Expanding range of fluororadiography

Siemens also introduced QuattroVision imaging, with a 2048 ¥ 2048 pixel matrix and a 10-bit gray scale, for its FLUOROSPOTT T.O.P. digital fluororadiography system. This technology expands the application of fluororadiography to include skeletal and thoracic diagnostics, according to Siemens.

A new generation radiology information system (RIS) was recently introduced from Per-Se Technologies (Atlanta). The ProgRIS 98 release features advanced capabilities such as a web-enabled report browser that gives referring physicians access to reports from any internet-connected computer, at any time, without installing special software.

The three-tiered client/server architecture improves remote access for physicians and transcriptionists, according to Per-Se. In addition, two-way communication between ProgRIS 98 and picture archiving and communication systems (PACS) support the tracking of image histories. The ProgRIS 98 also incorporates voice recognition technology.

ProgRIS 98 runs on a Windows 95 or Windows NT client with NT or UNIX servers and an SQL-compliant relational database. The system is designed for single and multi-site hospitals and imaging center networks.

The company also offers an optional Mammography Information Reporting and Tracking module, fully integrated with the base ProgRIS. This module features direct or check-list entry of mammographic findings, automated patient report generation, tracking of patient medical history, and recommended follow-ups, pathology results, and statistical reporting. According to Per-Se, the module is based on the American College of Radiology (ACR) BI-RADS [Breast Imaging Reporting and Data System] standard and complies with all applicable ADR, MQSA, and Medicare requirements.

Consumer electronics companies continue to grab more of the medical imaging market. The Medical Systems Division of Sony Electronics, Inc. (Montvale, NJ), for example, recently introduced two high-resolution, black-and-white thermal printers designed for radiology, ultrasound, and the cardiac catheterization lab.

The UP-980, a Multiscan® video graphic printer, incorporates an advanced thermal print head and offers 256 gray-scale control, according to Sony. The printer features two frames of memory and a selectable multiple print mode that allows for printing two, four, or six images per sheet. The UP-960, also featuring 256 gray levels, is an international model. Both printers accept NTSC and PAL signals.

The company now provides a blue transparency medium for the UP-980 for printing black-and-white images on transparent film, designed for radiology applications that require "quick reference," such as sports medicine, c-arm imaging, and ultrasound.

Medical computer display

Sony has also introduced its first medical computer display. Developed for patient monitoring applications such as bedside display or central monitoring in the operating room, the PGM-100P1MD features a variable resolution of 640 x 480 to 1280 x 1024 dots. The monitor incorporates Multiscan capability, and an "anti-reflection coated" Trinitron® cathode ray tube (CRT) that clearly displays information in brightly lit environments, according to Sony. The display's "splash-proof" cabinet is designed to protect the system from liquid spills.

Still image recorder

To enable medical images to be stored digitally on a 2-3/4" data MiniDisc, Sony has developed a digital still image recorder. The DKR-700/1 receives analog or digital signals of black-and-white or color images.

"Though medical procedures currently are being recorded on videotape, more and more of the medical community is using digital mediums to archive, transfer, and present this information. With the DKR-700/1, Sony provides the ideal system to transform video into a digital format," said Jim Sandy, vice president of medical systems for Sony Electronics' Business and Professional Group.

According to the company, the DKR-700/1 can digitally store and play back from 100 to 1,000 still images of standard NTSC video on a single 140-megabyte data MiniDisc. Images also may be retrieved from the disk by an appropriately configured personal computer.

Anticipating the much-dreaded year 2000 problem for computer systems (generally programmed to interpret "00" as the year 1900), GE Medical Systems (Milwaukee, WI) announced in March that it has developed a program to help its customers avoid this problem in their radiology equipment.

"Year 2000 is an issue that we have taken very seriously," said Jeffrey R. Immelt, president and CEO of GE Medical Systems. "We have anticipated this issue for some time and are offering a Year-2000 warranty on new system purchases. We've also committed ourselves to providing software updates on currently manufactured systems at no charge to our customers," he explained. For older systems that are no longer manufactured by GE, the company said it would offer either a software solution or "functional workaround." GE's Year-2000 updates will be available over the next 18 months.