Before you close in on that low-priced CT scanner, think about space. Room configurations require careful planning, and you must also prepare for site inspections that can ultimately result in delays and extra costs if not done properly. To help mitigate these hassles, a carefully designed plan by a qualified professional specifying floor plans, equipment placement, plumbing, power requirements, shielding, and other potential safety measures should be composed for all CT site locations. (Keep in mind, the site planning information below is primarily for reference. Local and state requirements; site conditions; and personal preferences may also have a major impact on your final layout).
Computed Tomography systems are typically located in the ER, or a radiology suite. Sometimes they can also be found near cath labs and cardiology suites. When planning to implement one of these systems in a facility, it’s not just about the scan room itself, but also the surroundings. It is necessary to consider uncontrolled areas above and below the facility (especially PET/CT) as well as those on the same level.
Proper planning should be done by a qualified expert that has knowledge of both the clinical operation of an imaging facility and radiation protection design methods for CT scanners. Below we’ve laid out CT Scanner site planning.
Ceilings and/or floors with occupied areas above or below CT scan rooms will most likely require shielding. Uncontrolled areas with high occupancy should be located as far from the CT exam room as possible. If uncontrolled areas are located either above or below the PET uptake and imaging rooms, the spacing between floors may need additional shielding. Moreover, floors need to be able to support the additional weight associated with added shielding.
Recommended ceiling heights for exam rooms should be at least 8ft.Typically, it is presumed that the patient is about 1 meter above the floor; and the dose rate is calculated at 0.5 meters above the floor (for rooms on top) and at 1.7 meters above the floor (for rooms below the exam room). Additional shielding is recommended for the nursing stations, the control room, and even vertical barriers.
The patient and the CT scanner itself are considered “sources of radiation” to personnel and the public. Technicians that work directly with the patients are prone to being exposed to the most doses that can stem from patient injections, patient positioning, and unavoidable exposure during imaging. Dose levels in controlled areas are subject to ALARA (As Low As Reasonably Achievable) considerations with the maximum limits said to be 50 mSv per year.
Portable lead shields can be used effectively to shield patients in uptake rooms. Other shielding considerations also include walls generally requiring 0.5 to 1.0 inch lead, doors needing 0.25 to 0.5 inches lead; and viewing windows should generally be leaded glass or acrylic.
The gantry can be cooled with chilled water derived from a closed loop connection from either an onsite chilled water supply or the heat exchanger. Chilled water supply must be available onsite in order to supply the heat exchanger that is located inside the gantry. If the facility will not supply chilled water, a heat exchanger cabinet is needed. The heat exchanger cabinet is then cooled with an outdoor cooling unit. As for an air-cooled gantry – this type of gantry has integrated cooling fans for air intake and air exhaust. In this instance, room air is used as cooling air, but requires thorough speculation (i.e., room size, thermal insulation, etc.) to ensure the temperature range of air needed for the system will be properly maintained.
The CT exam room is recommended to remain anywhere from 64-75 degrees Fahrenheit (18-24 degrees Celsius). The rest of the CT suite can be set as low as 59 degrees to 75 degrees. It is absolutely imperative that the climate be maintained at all times, even non-operating hours such as weekends, holidays, and overnight. Heat output in one section of the facility should not change the humidity and temperature in other areas. If this is a cause for concern, the exam room should be individually controlled to meet the temperature requirements.
Construction for a CT imaging center or mobile CT sites need to be performed in compliance with all applicable local and national electric codes (NEC) and regulations. Power requirements such as supply configuration, line voltage, branch power, and circuit breakers will vary based on factors such system requirements and power consumption (whether it is standard water/water heat exchanger or air cooled system, or has an optional water/air split cooling system). Do keep in mind that the exam room should contain at least one emergency power off button.
If you have questions or difficulty with your CT project planning, do not hesitate to contact me. I am here to help!
MRI, CT & PET/CT Specialist