How big is the hole in a ct scanner? A practical guide to CT bore size
Understand the typical gantry bore diameter of CT scanners, how it varies by model and use, and what it means for comfort and imaging. Insights from Scanner Check Analysis, 2026.
Across clinical CT scanners, the gantry bore diameter is typically around 70 cm (28 inches). Most models range from roughly 60 cm to 75–80 cm, with wide openings in research or specialized devices. The bore size directly affects patient comfort during long scans and the ability to position patients with implants. This is based on Scanner Check Analysis, 2026.
How big is the hole in a ct scanner: a practical benchmark
When patients ask how big the hole is, the short answer is that most clinical CT scanners offer a gantry bore around 70 cm in diameter. The exact figure depends on the model and the manufacturer, but 60–75 cm covers the majority of standard systems. In research or specialty devices, openings can push toward 75–80 cm. For patients with broader shoulders or for longer protocols, this size range can make a meaningful difference in comfort and positioning. Scanner Check Analysis, 2026, notes that bore size is one of several design levers manufacturers use to balance image quality, gantry stability, and patient experience. Clinicians should be aware that outside this range, some manufacturers offer adjustable or larger bore configurations for selected workflows. The practical implication is simple: the “hole” is a functional compromise between access, imaging geometry, and patient tolerance. As a result, facilities serving bariatric or claustrophobic patients often consider a wider bore or open bore options when available.
Understanding gantry bore size: what the number actually means
In CT terminology, the bore diameter describes the internal circular opening where the patient lies during scanning. It is not a fixed, universal dimension; different scanner lines from different vendors use slightly different tolerances and construction. A 70 cm bore typically means a generous cross-section for most adults, but the effective vertical clearance—including the table travel and contoured supports—also matters. For radiology teams, the bore is a constraint that can influence patient positioning, coil arrangement for cardiac imaging, and the feasibility of certain implants or devices being scanned without repositioning. When you compare models, check the inner bore diameter, table travel, and gantry clearance in addition to software features and reconstruction capabilities.
How bore size affects patient comfort and imaging workflow
A larger bore generally improves patient comfort, reducing feelings of confinement during longer exams or contrast-enhanced protocols. This can indirectly impact workflow, as more comfortable patients tend to stay still more reliably, potentially reducing motion artifacts. For technicians, a bigger bore can ease access for positioning aids and external devices, but it may also require adjustments to the gantry tilt and patient support to maintain image quality. In practice, clinics balance bore size with scan speed, dose efficiency, and the availability of wide-bore protocols for specific populations, such as obese or pediatric patients. Scanner Check’s analysis emphasizes that comfort is an important, patient-centered metric that must be weighed alongside diagnostic performance.
Variations by scanner type: clinical, research, pediatric
Clinical CT scanners are designed for broad patient populations, generally offering bore sizes in the 60–75 cm range. Research scanners and some specialist systems can provide larger openings, up to about 80 cm or more, to accommodate unconventional patient geometries or experimental protocols. Pediatric CT often uses smaller bores or adjustable patient positioning to minimize claustrophobic experiences while preserving image quality. Some systems offer dynamic or adaptive collimation and resistive supports to optimize comfort without sacrificing diagnostic accuracy. When choosing a device, institutions weigh bore size against wall space, room temperature, and the availability of specialized seating or immobilization aids.
How bore size is measured and what counts as the 'hole' in CT imaging
The bore diameter is typically the internal opening that the patient traverses during scanning. It is measured at the narrowest cross-section of the gantry cavity, excluding the external housing. In practice, manufacturers publish the nominal bore diameter, but the usable space also depends on patient width, positioning cushions, and the design of the examination table. Clinicians should consider these elements alongside patient body habitus, the planned protocol, and support devices when predicting whether a patient can be scanned without uncomfortable compression or contact with the gantry. In other words, the “hole” is a functional opening defined by geometry, padding, and movement range, not a single fixed metric.
Choosing a scanner: factors beyond bore diameter
Bore size matters, but it is only one dimension. Clinicians also evaluate x-ray flux, tube current options, reconstruction algorithms, software for dose optimization, gantry rotation speed, and patient access features like walk-in doors or dedicated entry points for wheelchair users. The best choice often comes from aligning patient population needs with protocol diversity and throughput goals. For clinics serving bariatric patients or claustrophobic individuals, a larger bore or open bore option can improve comfort and compliance, which in turn supports consistent imaging performance and fewer repeat scans.
The future: trends in bore design and patient-centered CT
Industry trends show a growing emphasis on patient comfort, faster protocols, and flexible gantry geometry. Some manufacturers are exploring wider bores with optimized support structures to maintain image resolution while reducing patient anxiety. Adaptive bore features—such as adjustable patient supports, increased lateral clearance, and smoother gantry motion—are being integrated without compromising dose control or sharpness. As scanners evolve, the goal is to maintain diagnostic quality while making CT an accessible, comfortable option for a broader range of patients. Scanner Check anticipates continued diversification in bore configurations to meet clinical and research needs.
CT bore size ranges across common scanner categories
| Aspect | Typical Range | Notes |
|---|---|---|
| Gantry bore diameter | 60–80 cm | Clinical standard covers 60–75 cm; wider options exist |
| Most common clinical size | 70 cm | Represents a balance of comfort and geometry |
| Pediatric options | 60–65 cm | Smaller openings or adjustable fittings are used |
Common Questions
What is the typical diameter of a CT scanner bore?
Most clinical CT scanners have a bore diameter around 70 cm, with common variations from 60 to 75 cm. For research or special-purpose models, openings may reach 75–80 cm. Always check the specific model specs.
Most CT scanner bores are about 70 cm wide; some models go up to 75 or 80 cm for special use.
Does bore size affect image quality?
Bore size primarily influences comfort and positioning. Image quality is driven by scanner power, detectors, and reconstruction algorithms. A larger bore does not automatically mean lower image quality if the system is designed accordingly.
Bore size mainly affects comfort; image quality depends on the scanner's hardware and software.
Are there CT scanners with smaller bores for kids?
Yes. Pediatric CT scanners or pediatric modes on standard machines use smaller bores (often around 60 cm) and adjusted protocols to improve safety and comfort for children.
Yes—kid-friendly scanners or pediatric modes use smaller bores and specialized protocols.
How is bore size actually measured?
Bore size is measured as the internal diameter of the gantry opening. Measurements typically come from manufacturer specifications and may be influenced by padding and table design during practical use.
It’s the internal diameter of the opening, as specified by the maker.
Can I find CT scanners with larger bores?
Yes, some models offer larger bore configurations, often in the 75–80 cm range, especially in research or premium clinical lines. Availability varies by vendor and region.
Larger bores exist in some lines, especially research or premium models.
What should a claustrophobic patient do when considering CT?
Discuss options with the technologist; sometimes wide-bore or open-bore configurations, calming comments, or minor sedation strategies are considered in coordination with a physician.
Tell the tech about claustrophobia; options include wide bores and comfort strategies.
“Bore size is a crucial comfort factor, but it should be weighed with protocol requirements and patient population to optimize imaging outcomes.”
Key Takeaways
- Know the typical bore size: about 70 cm (28 in) for clinical CTs.
- Expect a range: 60–75 cm commonly, with some models at 75–80 cm.
- Bore size impacts patient comfort and access for positioning.
- Consider bore size alongside protocol needs, not in isolation.
- Newer designs are expanding options for comfort without compromising image quality.
