CT Machine Site Plan Checklist

Why is CT machine site planning important? It can save you a huge amount of trouble in the long run. Before you close in on that low-priced CT machine, think about space and all other requirements for your device’s site. Room configurations and preparation for site inspections require careful planning which can ultimately result in delays and extra costs if not properly set-up. To avoid this, a carefully designed CT site plan from a qualified professional specifying floor plans, equipment placement, plumbing, power requirements, shielding, and other safety measures should be used for all CT machine 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 (CT) machines are typically located in the ER, or a radiology suite. Sometimes they can also be found near catheterization (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 considerations for a CT machine site plan checklist.

Shielding Considerations

Ceilings and/or floors with occupied areas above or below CT machine scanning rooms will most likely require shielding to reduce radiation levels. 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.

Ceilings for exam rooms are recommended to be at least 8 feet high. 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 machine 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 (millisieverts – a radiation measurement unit) per year.

What can be used for shielding? 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.

Gantry

Another important part of CT machine site planning is the gantry, the ring the patient is placed in. It 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 required temperature range of air needed for the system will be properly maintained.