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Question 588
Biophysics → General
Classification
Question
SSBAQuestion Header
Which ionising particle is approximately equal in size to an electron but carries a positive charge and is used in PET imaging?
Question Stem
Select the single best answer.
Options
A
Alpha particle
B
Beta particle
C
Positron
D
Gamma photon
E
X-ray photon
Explanation
A positron is approximately equal in size to an electron but has a positive charge. Positrons are artificial sources of ionising radiation used in positron emission tomography.
Option Validity
A) An alpha particle contains two protons and two neutrons.
B) Beta radiation consists of negatively charged electrons.
D) Gamma radiation consists of high-energy electromagnetic photons.
E) X-rays are electromagnetic radiation rather than positively charged particles.
Further Reading
Saxena R. Textbook for MRCOG-1. Chapter 9: Biophysics, pp.278–279.