IMAGE PERCEPTION

Question 1

Identify 3 perceptive skills/areas of knowledge required by a person reporting diagnostic images. (3 marks)

Answer 1

1 mark: Ability to see fine details and distinguish areas of low contrast.

1 mark: Ability to extract the region of interest from the background and effectively search the radiograph.

1 mark: Pattern recognition and knowledge of normal vs. abnormal appearances, including normal variants.

Question 2

A reporting radiographer is doing a visual search on a chest X-ray looking for possible lung nodules. What do you understand by the term ‘visual search’ in this context? (3 marks)

Answer 2

• The radiographer needs to search within the useful visual field to identify the target.
• Target: The visual stimulus being searched for (lung nodules).
• Useful visual field: The area within the field (lungs) which the observer needs to fixate in order to detect the target.

Question 3

During a reporting session, a radiologist makes the following two visual errors. Explain what has happened during each one:
a) Detection error (2 marks)
b) Interpretation error (2 marks)

Answer 3

detection error - observer has adequately fixated close to the target or region of interest but has failed to to detect the stimulus
The fixation is below the criterion time for detection.

• interpretation error - observer has adequately fixated at the target /region of interest for greater then the criterion but filed to identify it as stimulus

target is observed but unidentified