Technical Errors & Artifacts
The 5 different types of technical errors
What is Receptor Placement, Receptor Handling, Vertical Angulation, Horizontal Angulation, Cone cuts
What is type(s) of handheld x-ray device used for in dentistry?
MaxRay
NoMad
What type of radiation is used in dental imaging?
X-radiation (x-rays)
Name two main types of digital image receptors used in dentistry.
Direct sensors (e.g., CCD or CMOS)
Indirect systems (e.g., PSP plates – photostimulable phosphor plates)
Overexposure is defined as an image that is
A way to avoid underexposure error
Wait for full exposure cycle (see + hear it)
Where should the operator stand when using a handheld x-ray device?
Behind the safety barrier
What is ionizing radiation?
Ionizing radiation has enough energy to remove electrons from atoms, creating ions that can damage living tissue and DNA.
What controls the image’s lightness and darkness in digital radiography?
Exposure settings (kVp, mA, time) and software adjustments (brightness/contrast).
What is image noise in digital radiography?
Random variations in brightness or pixel intensity that reduce image clarity, often caused by low exposure or electronic interference.
What radiographic errors may result from patient movement during imaging procedures?
Blurring of the image, Cone cuts, Distortion, Loss of diagnostic value
What is the main safety advantage of using the backscatter shield?
The backscatter shield reduces the operator’s exposure by absorbing radiation reflected from the patient.
What is the ALARA principle?
“As Low As Reasonably Achievable.”
It means minimizing radiation exposure through proper technique, shielding, and justification of need.
What is one main advantage of digital imaging over film-based radiography?
It offers immediate image viewing, lower radiation exposure, and easy image enhancement or storage.
What happens if PSP plates are exposed to ambient light before scanning?
The image fades or becomes overexposed, as light erases the latent image.
Reversed receptor (film or sensor) placement is due to what incorrect action?
Barrier of PSP plate is reversed (Barrier error)
PSP is inserted backward in bite block (XCP setup error)
What exposure technique should be used to optimize patient safety and image quality?
Use shortest possible exposure time
Maintain proper distance and alignment
Ensure collimation to the area of interest
How does filtration protect the patient?
Filtration removes low-energy, non-penetrating x-rays from the beam, reducing patient skin dose and improving beam quality.
What is spatial resolution in digital imaging?
Spatial resolution refers to the ability to distinguish small structures in an image, measured in line pairs per millimeter (lp/mm).
How should PSP plates be handled after exposure?
They should be scanned immediately or stored in a light-tight container to prevent image loss.
What are the causes of a dark (overexposed) radiograph?
Excessive exposure time
High kVp or mA setting
Improper processing time
What maintenance checks are essential for handheld x-ray devices?
Battery condition
Backscatter shield integrity
PID alignment
Calibration accuracy
Explain the inverse square law in radiation safety.
Radiation intensity decreases with the square of the distance from the source — doubling distance reduces exposure to ¼ of the original level.
What are common artifacts seen in digital imaging?
Scratches or dust on PSP plates
Double images from un-erased plates
Bite marks or bending on sensors
Image noise due to low exposure
What is the annual maximum permissible dose (MPD) for occupational exposure?
50 mSv (5 rem) per year for radiation workers, according to the NCRP (National Council on Radiation Protection and Measurements).