Ceiling insets add a sense of height to the MRI suite at the University of Iowa, Iowa City.

CT, PET, and MRI scanners are leading diagnostic devices for disease detection today. Inversely proportional to their notable detection success rates are their inherent limitations of physical dimension, acoustical control, and visual proportion in existing imaging centers.

Intimidating high-tech equipment in patient-care areas, glaring lighting, and high-velocity mechanical equipment are just several issues that need to be addressed in the design process when siting large scanners. If health care leaders are aware of these challenges during the diagnostic suite design process, the room can be economically effective while meeting higher levels of patient satisfaction.

Diagnostic treatment rooms are designed to carry massive pieces of equipment, and as such, both height and volume need to be analyzed carefully. Because of a patient’s natural apprehension about diagnosis, the size of the room should be in scale and in proportion to the size of the equipment. Higher ceilings are required for ceiling-mounted, articulating arms that administer contrast injections. Raised ceilings also accommodate indirect lighting that is more conducive to healing environments and pleasing to patients than harsh direct lighting.

Designers at HDR find it very difficult to work in spaces with less than 12-foot floor-to-floor height in existing structures and recommend at least 14 feet whenever possible. Conversely, a room that is excessively disproportionate may appear overwhelming. Keeping in mind manufacturer-recommended square-footage guidelines, adept planners chart a size needed for a “worst-case scenario” or the largest common denominator in equipment footprint and plan accordingly, rather than slavishly following vendor-specific current requirements. Thus, the room can be adapted to future diagnostic upgrades.

In one recent HDR project, a medical center’s existing master plan provided optimal circumstances for an intriguing expansion. Several floors of open space, essentially between a surgery center supported on stilts and a parking garage at grade, were available as an “in-fill” opportunity.

Architects created a design for the medical center’s radiology department expansion sandwiched between the parking garage and surgical floor interstitial space, and connected it vertically. From a stacking perspective, this interstitial buffer proved to be highly successful. Mechanical and electrical systems were able to connect directly through the floor above, providing short utility runs and more efficient mechanical, electrical, and plumbing (MEP) systems.


A lesson learned, however, is that when utilities feed directly from interstitial ceiling space above, the design should include protection from water and moisture penetration.

In this case, a sprinkler head failed during a water-pressure test, destroying an uncrated diagnostic device causing about $1 million worth of damage, for which the contractor was ultimately responsible. Within a year of occupancy, a frozen water line burst as a result of mechanical failure. Water migrated to the low point and damaged the same room again, requiring a complete replacement of the equipment.

Following this expensive lesson learned, designers prescribed the installation of a sealer and curb around the floor perimeter and all penetrations. The cost for preventing the incident again was less than $50,000, not appreciable compared with $2 million in gross equipment losses.

Another component to be cognizant of is point of entry and how equipment will move to its final resting location, particularly in the case of MRI scanners. It is preferable to identify transportation routes that begin near loading docks or secondary entrances to preclude moving large cartons through the main entry. Assurances also are necessary in securing adequate corridor widths and structural floors with appropriate reinforcement to accommodate rolling-load design criteria.


Wood floors bring warmth to a CT suite in the Georgia Cancer Center of Excellence, Grady Health System, Atlanta.

Conveniently, new PET/CT scanners have similar size, weight, and clearance requirements as older CT scanners. However, these state-of-the-art scanners now have specifications for accompanying all-digital instrumentation. Furthermore, flat-screen monitors, PACS (picture archiving and communications system), and other equipment are sensitive to humidity and temperature and must have dedicated heating, ventilation and air conditioning (HVAC) systems adjacent to the room, or on the exterior of the building.

Generally speaking, the immediate suite includes:

  • Patient diagnostic space
  • Control room
  • Patient holding
  • Equipment space for computers, power conditioners, and backup uninterrupted power supply systems.

These expansions, especially in already close-knit suburban settings, have acoustical and visual ramifications. In the case of one Midwestern hospital situated in a residential neighborhood, new MRI and PET/CT scanner suites were expanded in the existing building. Air-handler and chiller units, as well as a cooling tower, were adjacent to the front entry and an outdoor dining space, generating noise and visual pollution. Anticipating resident and visitor reproach, planners included screens in the original design to block unattractive industrial-type equipment and installed silencers to shield residents from mechanical vibration, creating a more subdued and aesthetically pleasing exterior space.


In the case of PET scanners, regard should be given for space to accommodate requisite lead lining around the walls of both the scanning room and adjacent radioactive hot laboratory. And while overhead ductwork is standard, in a case where the 12-foot minimum was not possible, ductwork was routed via a technique similar to exterior buttressing. The caution here is that extraordinary duct lengths can lead to static pressure problems unless installation methods are nearly perfect.

The ideal condition for expansion and renovation of diagnostic imaging suites is ample space for scanning equipment, allowing clearance for servicing and ease of use for necessary procedures. Keeping the room size proportionate to the physical dimensions of equipment will allow the space to be less intimidating to patients. In addition, a scan room generally should be quiet, with indirect and multilevel diffused lighting.

It is also crucial for adjacent support space to house equipment for temperature control and humidity of sensitive digital equipment. All chillers and air-handling units should be buffered from their surroundings via screens and silencers where possible. And, of course, overhead openings and slabs should be sealed appropriately before installing expensive equipment.

In the end, the biggest challenge is to create diagnostic imaging suites that are highly efficient, yet conducive to a healing patient environment, notwithstanding existing site constraints.

Michael D. Doiel, AIA, is a senior vice president and health care principal with HDR in Chicago. He can be reached at [email protected].