Pearson Edexcel · GCSE · Biology
Course version: 1BI0 · Version from Sept 2016
2.11B Explain how the difficulties of accessing brain tissue inside the…
Full specification wording
Topic 2 – Cells and control: 2.11B Explain how the difficulties of accessing brain tissue inside the skull can be overcome by using CT scanning and PET scanning to investigate brain function
Brain tissue is enclosed by the skull, so it cannot be observed directly without invasive surgery, which carries risk.
Checked against the Pearson Edexcel 1BI0 specification (opens in a new tab) on .
- Point 10 of 16
Study notes
From the checked teaching notes for this specification point.
The idea
Brain tissue is enclosed by the skull, so it cannot be observed directly without invasive surgery, which carries risk. Medical imaging overcomes this by producing images of the living brain from outside the head. A CT (computerised tomography) scan uses X-rays taken from many angles to build detailed structural images, revealing tumours, bleeding or damage. A PET (positron emission tomography) scan uses a radioactive tracer to show which regions are metabolically active, so it reveals function such as which areas are working during a task. Together they allow structure and activity to be investigated without opening the skull. In a multiple-choice question, match the technique to its purpose: CT for structure, PET for activity/function.
What earns the marks
- States the difficulty: brain tissue is protected by the skull and cannot be accessed directly without risky invasive surgery.
- CT scanning uses X-rays to produce detailed images of brain structure, such as tumours or damage.
- PET scanning uses a radioactive tracer to show metabolic activity, revealing which regions are functioning.
- Explains that these scans investigate the living brain from outside the skull, avoiding invasive surgery.
- Correctly matches each technique to its purpose (CT = structure, PET = function/activity).
Common mistakes and how to put them right
Claiming CT scanning shows brain activity.
Put it right: CT reveals structure, while PET reveals metabolic activity and function.
Thinking PET scanning uses X-rays.
Put it right: PET uses a radioactive tracer, whereas CT uses X-rays.
Believing scans require surgery to access the brain.
Put it right: Scans image the brain from outside the skull without invasive access.
Exam tips
- Link each scan to one purpose: CT = structure, PET = function/activity.
- Remember the shared advantage: both investigate the living brain without opening the skull.
- Eliminate options that confuse the energy source or tracer used by each technique.
Try the lesson
The start of the Topic 2 – Cells and control: 2.11B Explain how the difficulties of accessing brain tissue inside the skull can be overcome by using CT scanning and PET scanning to investigate brain function lesson, made from checked teaching notes for this specification point.
Have a go first
A doctor needs to examine a patient's brain without cutting through the skull. Which statement best explains why a CT scan is useful for this?
There is more to this lesson
The full lesson goes on to check your understanding and help you earn the marks. Create a free account to carry on, with your progress saved.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge
Test your understanding of Topic 2 – Cells and control: 2.11B Explain how the difficulties of accessing brain tissue inside the skull can be overcome by using CT scanning and PET scanning to investigate brain function
Active recall beats re-reading. Take an instant quiz now to test what you’ve learned and lock it into long-term memory.
A week of Premium from your first lesson · Then the free plan continues · No card, no charge