FRCR Part 1 (Radiology) - CR1 - specimen questions (physics module)

1 Concerning the Compton effect:

1. There is interaction between a photon and a free electron.
2. The larger the angle through which the photon is scattered, the more energy it loses.
3. The wavelength change produced depends upon the scattering material.
4. High energy radiation is scattered more than lower energy radiation.
5. The amount of scattering that occurs depends on the electron density of the scattering material.

2 Concerning digital radiography (DR):

1. Phosphors may be used in the detector.
2. The receptor signal is used to determine exposure cut-off time.
3. The image can be viewed within five seconds of the exposure.
4. Pixel dropout is a recognised artefact.
5. The receptor dose indicator gives a record of patient dose.

3 Radiological image unsharpness increases:

1. if shorter exposure times are used.
2. as the object to receptor distance increases.
3. as the target angle decreases.
4. if a grid is used.
5. as the focal spot size increases.

4 In automatic mode fluoroscopy, the patient entrance surface dose rate:

1. usually increases with image intensifier field size.
2. depends on the added filtration.
3. is independent of the kV-mA characteristic used.
4. doubles if the patient-intensifier face distance is halved.
5. should be less than 50 mGy min-1.

5 Concerning The Ionising Radiations Regulations 1999:

1. Local Rules are required for a controlled area.
2. Only classified workers can enter a controlled area.
3. The annual effective dose limit is 30 mSv for employees aged over 18 years.
4. Personal dosimeters should be issued for periods no greater than one month.
5. A radiation protection adviser is responsible for managing staff radiation safety in a radiology department.

6 Concerning The Ionising Radiation (Medical Exposure) Regulations 2000:

1. Overall responsibility for keeping dose to the patient as low as reasonably practicable rests with the practitioner.
2. The practitioner is the only person entitled to authorise an x-ray exposure.
3. Only doctors and dentists are permitted to request an x-ray.
4. The person performing quality control tests on an isotope calibrator must have training.
5. The enforcing authority is the Health and Safety Executive.

7 Radionuclides:

1. are those nuclides having more neutrons than protons.
2. may emit x-rays.
3. decay exponentially.
4. do not occur naturally.
5. may be produced in a cyclotron.

8 Concerning computed tomography:

1. A CT number of 0 is assigned to water.
2. Image quality is limited by electronic noise.
3. Axial image resolution is improved with reduction in slice width.
4. An unfiltered x-ray beam is used.
5. The typical effective dose for a CT head scan is 10 mSv.

9 Signal to noise in MRI is increased with:

1. a decreased matrix size.
2. a longer TE.
3. a thicker slice.
4. a smaller field of view.
5. the use of a higher main magnetic field.

10 Concerning diagnostic ultrasound:

1. The higher the transmitted frequency, the greater the depth that can be scanned.
2. In abdominal scanning it typically has a wavelength in soft tissue of about 0.5 mm.
3. It is reflected from a surface between two media that have different acoustic impedances.
4. The ultrasound beam can be focussed.
5. Ionisation of cell water may occur at frequencies greater than 5 MHz.

Answers:

1a: T, 1b: T, 1c: F, 1d: F, 1e: T
2a: T, 2b: T, 2c: T, 2d: T, 2e: T
3a: F, 3b: T, 3c: F, 3d: F, 3e: T
4a: F, 4b: T, 4c: F, 4d: F, 4e: T
5a: T, 5b: F, 5c: F, 5d: F, 5e: F
6a: F, 6b: F, 6c: F, 6d: T, 6e: F
7a: F, 7b: T, 7c: T, 7d: F, 7e: T
8a: T, 8b: F, 8c: T, 8d: F, 8e: F
9a: T, 9b: F, 9c: T, 9d: F, 9e: T
10a: F, 10b: T, 10c: T, 10d: T, 10e: F