TSO X-Ray Image Interpretation 3 — Questions and Answers
Question 1: On a dual-energy X-ray system, items with HIGH atomic numbers (Z-number) typically appear in which color?
- Blue or green (Correct answer)
- Orange or amber
- Red
- Transparent
Correct answer: Blue or green
High-Z materials such as metals are assigned blue or green colors on dual-energy X-ray systems to help officers quickly identify them.
Question 2: A carry-on bag passes through X-ray and shows a cluster of small, bright white circular objects grouped together. The MOST likely concern is:
- Ball bearings or metal projectiles that could be components of an IED (Correct answer)
- Decorative jewelry items
- Vitamins or supplement capsules
- Coins collected loosely at the bottom of the bag
Correct answer: Ball bearings or metal projectiles that could be components of an IED
Clustered dense spherical objects resembling ball bearings are a recognized IED component signature requiring additional screening.
Question 3: Why is it important for TSOs to vary their focus point and scan speed when viewing X-ray images?
- To reduce visual fatigue and avoid missing items in peripheral areas of the image (Correct answer)
- To comply with TSA time quotas for bag processing
- To allow the machine's software to recalibrate between bags
- To ensure the conveyor belt speed matches the imaging rate
Correct answer: To reduce visual fatigue and avoid missing items in peripheral areas of the image
Varying scan speed and focus point counteracts inattentional blindness and ensures the entire image area is evaluated.
Question 4: Which of the following objects would appear MOST penetrable (darkest) on an X-ray image?
- A foam pillow (Correct answer)
- A steel padlock
- A glass bottle filled with water
- A ceramic tile
Correct answer: A foam pillow
Low-density foam absorbs very little radiation, allowing most X-rays to pass through and producing a very dark image.
Question 5: A bag contains what appears to be a book. However, the book's spine area shows a dense metallic line with small cylindrical objects. The TSO should:
- Resolve the anomaly through additional screening because this pattern is consistent with a book-bomb configuration (Correct answer)
- Clear the bag since books are permitted items
- Ask the passenger if the book is hardcover or paperback
- Swab the exterior of the bag for explosive traces only
Correct answer: Resolve the anomaly through additional screening because this pattern is consistent with a book-bomb configuration
Metallic components embedded within a book's spine can indicate a concealed device and must be resolved through additional screening.
Question 6: What is the significance of the 'effective atomic number' (Zeff) provided by dual-energy X-ray systems?
- It helps classify whether a substance is organic, inorganic, or metallic, aiding threat identification (Correct answer)
- It measures the exact weight of objects in the bag
- It indicates the radiation dose delivered to the contents
- It shows the manufacturer's safety rating for the X-ray machine
Correct answer: It helps classify whether a substance is organic, inorganic, or metallic, aiding threat identification
Zeff values are used to color-code materials by category, helping officers rapidly distinguish explosives, metals, and organics.
Question 7: A passenger's bag shows a large orange-amber blob obscuring a section of the image. What technique can the officer use to better evaluate what is underneath?
- Use the organic-stripping or color-inversion feature to suppress the organic layer and reveal underlying items (Correct answer)
- Rotate the bag 180 degrees and re-scan
- Manually move the organic item and re-scan the bag
- Flag the bag for a physical search without further X-ray review
Correct answer: Use the organic-stripping or color-inversion feature to suppress the organic layer and reveal underlying items
Organic stripping electronically removes the orange organic overlay to expose potentially hidden metallic or inorganic threat items.
TSO X-Ray Image Interpretation 3
On a dual-energy X-ray system, items with HIGH atomic numbers (Z-number) typically appear in which color?