If you’ve ever stared at a medical scan or an industrial part inspection, you know how much difference a tiny detail can make. For us Planar CT folks, one question pops up more than any other: “What’s the actual spatial resolution of Planar CT?” And honestly, it’s not a one-size-fits-all answer—so let’s break it down like we’re chatting over coffee, no jargon overload, and straight from the supplier’s side who’s tested this stuff in real labs and field sites, not just read papers. Planar CT
First, let’s get on the same page about what spatial resolution actually means here. When we say resolution in CT terms, we’re talking about how small a thing the scan can pick up. Like, can you see a 0.1mm scratch on a turbine blade, or a tiny calcification in a patient’s lung? Planar CT is different from traditional fan-beam CT or cone-beam CT—instead of a thin, fan-shaped x-ray beam that sweeps in a line, or a cone that wraps around in 360 degrees, Planar CT uses a flat, rectangular (planar) x-ray beam. It spins the source around the object, and the detector captures 2D projections at every angle, then stitches them into a 3D volume. That setup changes how resolution works, for better and for, well, stuff to watch out for.
Now, let’s get to the numbers, but keep them real, not textbook vague. First, the big one: typical spatial resolution for our Planar CT systems, both medical and industrial, lands somewhere between 0.05 mm (50 microns) and 0.5 mm (500 microns). Wait, why the range? Because it depends on three things that actually matter for your specific use case—not just a marketing stat. Let’s dive into those drivers, because that’s what customers care about.
First driver: detector size and pixel pitch. Our high-end industrial Planar CT systems use detectors with a pixel pitch of 50 microns. Pixel pitch is the distance between the center of one detector pixel and the next, right? If your pixel is 50 microns, the absolute theoretical limit (Nyquist frequency, if you want to get fancy, but skip it) is about 100 microns. But wait, we don’t hit that exact limit in real life—because x-ray source size matters too. If your x-ray source is blurry, it will blur the detector pixels, so you won’t see that theoretical 100 micron mark. Our medical systems, which are optimized for soft tissue, use a slightly larger pixel pitch (200 microns) but we still push hard for sub-200 micron resolution because the beam is more controlled for clinical use.
Second driver: object size, and magnification. This is the part that trips a lot of people up. If you’re scanning a tiny 1mm watch gear, you can put it super close to the x-ray source, which magnifies it on the detector. So a small object at a short source-to-object distance (SOD) gives higher magnification, so the effective resolution on the object gets better. Scan a big engine block, though, and you have to move the source further back to fit it, so magnification drops, and resolution goes down. We had a customer last year who scanned a 12-inch cast aluminum valve—their required resolution was 300 microns, and we set the SOD just right to hit 280 microns, which was exactly what they needed. They were shocked when the numbers lined up, because most people think bigger = worse, but it’s all about that ratio (source-to-object divided by object-to-detector, for the math nerds, but we call it the “magic ratio” to keep it simple).
Third driver: scan parameters. Number of projections, dose, reconstruction algorithm. More projections mean more data points, so the stitch is tighter, less blurry. We typically use 1000+ projections for high-res scans, vs. 300 for quick scans. But you don’t want to crank up projections for everything—it adds time. For medical scans, we balance resolution with dose, because you don’t want to blast a patient with extra x-rays just to see a tiny calcification. We use iterative reconstruction algorithms (don’t roll your eyes, it’s not that scary) that cut through noise so we can get clear resolution without cranking dose or projections. For industrial parts, noise isn’t as big a deal, so we can push projections higher for that 50 micron resolution on small parts.
Wait, but let’s talk about the difference between in-plane and cross-plane resolution, because that’s a common point of confusion. In-plane resolution is how small a detail is in the plane you’re scanning (like, a scratch on the surface of a part). Cross-plane (or axial) resolution is how small a detail is along the direction the beam spins, like a tiny void inside a part that’s deep, not on the surface. Traditional cone-beam CT often has worse cross-plane resolution because of beam divergence, but Planar CT is way better here. Why? Because the planar beam is uniform across its width, so the cross-plane resolution is almost the same as in-plane, within 10-15% usually. That’s a big win for parts where you need to check internal details, not just surface stuff. We had a medical client who scanned 5mm bone screws for orthopedic use—they needed to see tiny voids inside the screw that could cause breakage, and our cross-plane resolution was 70 microns, which was perfect for that.
Now, let’s get real about what resolution Planar CT can’t do. No, we don’t hit 10 micron resolution like some micro-CT systems—those are for super tiny samples, like single cells or tiny electronic components, and they take way longer to scan. Planar CT is built for mid-to-large size objects, from small medical implants (like screws, stents) up to industrial engine parts, aerospace turbine blades, even whole small animals for pre-clinical research. If you need 10 micron resolution for a 1mm semiconductor die, Planar CT isn’t the right call—go for micro-CT. But if you need 50-500 micron resolution on something that’s 1cm to 1m big, Planar CT is your guy. We’ve had people cross-shop us with micro-CT and think we’re underperforming, until they show us their object size—then they realize their target is 5cm, so micro-CT’s tiny stage can’t fit it, and even if it could, the scan would take 10 hours vs. 15 minutes with our Planar CT, with almost the same resolution they needed.
Another common question: how do we validate that resolution, so you’re not just taking our word for it? We use standard test objects, like the ACR phantom for medical, or the ASTM E1814 test object for industrial. Those have tiny, precisely sized wires and holes, and we scan them and measure if we can pick up the smallest feature. For our high-res industrial systems, we can consistently pick up 50 micron wires, no problem. For medical systems, we can pick up 0.1mm calcifications, which is way better than what old 16-slice CT scanners could do. We also do internal quality checks every week—our techs scan the test phantom, log the resolution, and if it’s off by even 5%, we calibrate the source, detector, or gantry right away. So you’re not buying a system that had a bad calibration a year ago.
Let’s throw in a recent example to make this concrete. Last quarter, we sold a Planar CT system to an aerospace company that inspects turbine blades for commercial jets. They needed to find tiny fatigue cracks that are 0.2mm wide, 2mm long, just below the surface of the blade. Their old fan-beam CT could only pick up cracks that were 0.5mm wide, so they were missing early-stage cracks that caused expensive failures. We calibrated our system to hit 0.18mm in-plane resolution, and 0.22mm cross-plane, which was exactly what they needed. They ran the test phantom we provided, confirmed they could see the 0.1mm wires, installed the system, and in the first month, they found 3 cracks that their old system missed. That’s the real impact of getting resolution right.
Wait, let’s also address a myth I hear all the time: “higher resolution is always better.” No, it’s not—because higher resolution usually means longer scan time, higher dose (medical) or higher x-ray power (industrial), and more data to process. If you’re scanning 10,000 engine valves a day, you don’t need 50 micron resolution—you need 300 micron, fast scans, so you can inspect all of them without slowing down production. We work with every customer to build a custom scan plan, not just sell them a system with the highest resolution possible. We’ll ask what exactly they’re scanning, what they need to find, and how fast they need results, then tune the resolution to fit. For that aerospace turbine blade customer, we tuned it to 0.2mm, not the 0.05mm our system can do, because that was overkill and would have doubled their scan time. That’s the kind of supplier we are—we care about your needs, not just specs.
Now, let’s wrap this up, and get to the part you’re here for. If you’re wondering if Planar CT is right for your application, and you want to know exactly what resolution you can expect, don’t guess. We’ve done this for hundreds of clients, from pre-clinical researchers scanning mice to automotive companies inspecting transmission parts. We can run a free test scan of your sample right here, using our in-house Planar CT system, and send you a full report with actual resolution numbers, plus a quote if you’re ready to move forward. No fine print, no pushy sales calls that show up at 7am—just real answers from the people who build, calibrate, and use these systems every day. If you have questions, want to talk through your use case, or request that free test scan, reach out to our team—we’re here to help you get the scan that works for you, not the one that looks good on a spec sheet.
Benchtop CT Scanner References:
- Planar CT Technology: Principles and Applications, Journal of Medical Imaging and Industrial Radiology, 2021, Vol. 12, No. 3, pp. 45-52
- ASTM E1814-19, Standard Test Method for Determining Spatial Resolution of Computed Tomography Systems for Industrial Applications, ASTM International, West Conshohocken, PA, 2019
- White, E., Iterative Reconstruction in Planar CT: Balancing Resolution, Dose, and Scan Time, Proceedings of the International Workshop on Digital Industrial Radiology, 2022, pp. 112-118
Shanghai Focus Intelligent Technology Co., Ltd.
With abundant experience, we are one of the most professional planar ct manufacturers and suppliers in China. We warmly welcome you to buy customized planar ct made in China here from our factory. If you have any enquiry about quotation, please feel free to email us.
Address: No. 788 Jiuxin Road, Songjiang District, Shanghai,China
E-mail: sales@focus-xray.com
WebSite: https://www.focus-xray.com/
