Does Industrial X-ray CT Scanning Affect Manufactured Materials? What the Research Shows

Why This Question Comes Up in Manufacturing

As industrial X-ray computed tomography (CT) becomes a standard inspection tool across aerospace, medical device, automotive, and consumer-goods manufacturing, a reasonable technical question often follows:

Can exposure to X-rays during CT inspection alter the material being inspected?

This concern typically stems from awareness of radiation processing applications where ionizing radiation is intentionally used to change material properties. However, inspection and processing operate in fundamentally different absorbed-dose regimes.

Peer-reviewed academic literature and international technical standards consistently show that routine industrial CT inspection operates at absorbed dose levels far below those required to cause measurable changes in metals, ceramics, or most engineering polymers used in manufacturing.

This article summarizes:

• What “damage” means from a materials-engineering standpoint
• How radiation dose is measured and interpreted
• Why industrial CT is classified as nondestructive testing (NDT)
• What published research says about common manufacturing materials

What “Material Damage” Means in Engineering Terms

In manufacturing, material damage is not defined by exposure alone, but by measurable changes in performance or structure, such as:

• Alteration of micro-structures, deformation, or grain growth
• Mechanical property changes (strength, fatigue, or stiffness)
• Dimensional instability
• Chemical degradation affecting long-term performance

Academic studies evaluating the effects of radiation on materials assess these outcomes using various techniques, including tensile testing, fatigue testing, hardness measurements, thermal analysis, spectroscopy, and microscopy, rather than simply the presence of ionizing radiation.

Radiation Dose Explained: Gy, kGy, and mSv

Understanding why CT inspection is nondestructive requires understanding the radiation type and absorbed dose, or the amount of energy deposited. This measurement per unit mass of material is typically shown in Grays.

Absorbed Dose — Gray (Gy)

• 1 gray (Gy) = 1 joule of absorbed energy per kilogram of material
• This is the correct unit when discussing material response
• Used in materials science, polymer chemistry, and radiation processing

Kilogray (kGy)

• 1 kGy = 1,000 Gy
• Radiation processing applications (sterilization, polymer crosslinking) typically operate in the 10–100+ kGy range
• Most documented radiation-induced material changes occur here

Sievert (Sv) and millisievert (mSv)

• Used for human radiation protection, not material behavior
• Incorporates biological weighting factors
• Often cited in medical imaging, but not relevant for evaluating material damage

Key distinction:

Material effects are measured by absorbed dose (Gy), not effective dose (Sv).

Typical Absorbed Dose in Industrial X-ray CT Inspection

Industrial CT dose depends on part geometry, density, scan energy, and exposure time. Published measurements and industry practice show:

• Single CT inspections typically deposit absorbed doses in the milligray (mGy) to low-gray (Gy) range
• This is several orders of magnitude lower than radiation processing doses, which are intentionally selected to induce chemical or structural changes in materials. 
• Even repeated inspection scans rarely approach kGy-level exposures

Why Industrial X-ray CT Is Classified as Nondestructive Testing

The dose separation between industrial CT scans vs. sterilization, polymer crosslinking, curing, and degradation testing is the core reason CT inspection is considered nondestructive.

Industrial CT is categorized alongside:

• Radiography
• Ultrasonic testing
• Coordinate measuring machines (CMM)

Its widespread acceptance across:

• Aerospace qualification programs
• Medical device verification workflows
• Automotive production inspection

reflects decades of validation showing that inspection-level X-ray exposure does not alter manufactured components.

What Peer-Reviewed Research Says by Material Class

Metals and Metal Alloys

(Aerospace, automotive, consumer products)

Peer-reviewed tomography and materials-science reviews consistently show:

• X-ray photons at industrial CT energies interact via photoelectric absorption and Compton scattering
• These interactions do not produce displacement damage in metallic crystal lattices
• No measurable changes in:
  
  • Grain structure
  • Mechanical properties
  • Fatigue behavior
    have been reported at CT inspection doses

Key sources:

• García-Moreno et al., X-ray Tomography and Tomoscopy on Metals: A Review, 2023
• Paulis et al., Is CT Bulletproof?, 2019

CT is widely used specifically because it allows internal defect detection without altering metallic components.

Technical Ceramics and Glasses

Ceramics and technical glasses exhibit:

• Strong ionic or covalent bonding
• High resistance to ionization-induced structural change

Published literature shows:

• No observed microstructural or mechanical degradation at inspection-level X-ray doses
• CT is routinely used for ceramic casting validation, porosity analysis, and crack detection without material modification

Engineering Polymers Used in Manufacturing

(Non-biological, non-implant context)

Radiation-effects literature makes a clear distinction between:

• Inspection-level exposure
• Radiation-processing exposure

Peer-reviewed studies and international reviews show:

• Detectable chemical or mechanical changes generally occur at kGy-level absorbed doses
• Routine CT inspection doses do not produce measurable changes in standard engineering polymers when evaluated using mechanical or thermal tests

Best Practices for Dose-Conscious CT Inspection

For manufacturers with particularly sensitive materials or regulatory requirements, Nel PreTech will optimize scan energy and exposure time. A pre-scan consultation to avoid unnecessary repeat scans is also offered at no charge for added confidence. Pre- and post-scan comparison testing is also an option if needed. For most materials, these steps are typically precautionary and are not corrective actions.

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Key Takeaways for Engineers and Quality Teams

• Peer-reviewed research consistently shows no measurable structural or mechanical changes in metals or ceramics at routine CT inspection doses
• Polymer effects documented in literature occur at several orders-of-magnitude higher doses
• Industrial X-ray CT remains a validated, nondestructive inspection method across manufacturing sectors

If you have a project requiring CT scanning and would like to discuss it further, contact Nel PreTech today.