Ionising Radiation
Why are radioactive isotopes of the stable elements that occur normally in the body useful for tracing metabolic pathways? Because:
Such isotopes undergo chemical reactions that are identical to those of stable isotopes.
Radioisotopes are indistinguishable from non-radioactive isotopes of the same element.
Nuclear radiation can be detected outside the body and be used to produce an image of internal structures.
Radioactive forms of elements that exist naturally in the body do not pro-duce toxic effects when used as a radiopharmaceutical.
Such isotopes undergo chemical reactions that are identical to those of stable isotopes.
Radioactive forms of elements that occur naturally in the body will be handled by the body in exactly the same way as the non-radioactive isotope. Hence their location within the body can be traced by the gamma radiation they emit.
Such isotopes undergo chemical reactions that are identical to those of stable isotopes. Radioactive forms of elements that occur naturally in the body will be handled by the body in exactly the same way as the non-radioactive isotope. Hence their location within the body can be traced by the gamma radiation they emit.
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Which anatomical plane is usually displayed in a CT scan?A. Transverse
B. Sagittal
C. Coronal
D. Longitudinal section
What are isotopes? Atoms of the one element whose nuclei:
A. Contain the same number of protons and neutrons
B. Have different numbers of protons
C. Have different numbers of neutrons
D. Do not have the optimum neutron to proton ratio
What does the “maximum permissible dose” of radiation (100 mSv/5 year period) refer to?
A. The average dose for the general population as a whole
B. The dose for an individual not exposed to radiation through their work
C. The dose allowed to people exposed to radiation through their work
D. The dose above which radiation is likely to cause harm to humans
Why are radionuclides that emit low-energy gamma radiation preferred than other radionuclides for in vivo diagnosis using a nuclear medicine technique? Because:
A. Other forms of radiation are emitted with too much energy.
B. High-energy gamma radiation is not penetrating enough.
C. Most of the radiation will emerge from the patient’s body.
D. Sources of x-rays require more extensive technical support than gamma sources.
The advantage of computed tomography (CT) over conventional radiography is:
A. CT delivers lower doses than conventional radiography.
B. CT images are faster to acquire than conventional radiographs.
C. CT produces a cross-sectional image that is not obscured by overlying anatomical structures.
D. CT projects a 3D structure onto a 2D image.
Which of the following absorbed radiation dose equivalents would cause the most harm to your body?
A. 0.05 sievert per year to the whole body for the human lifespan (75 years) = 3.75 Sv
B. 1 sievert (acutely) to the gonads only
C. 40 sievert (acutely) to the heart only
D. 7 sievert (acutely) to the whole body
Which one of the statements about the penetrating ability of radiation is true?
A. 750 keV gamma rays are more penetrating than 750 keV x-rays.
B. 140 keV gamma rays are more penetrating than 60 keV x-rays.
C. 2 MeV beta rays (electrons) are more penetrating than 1 MeV gamma rays.
D. 1 MeV gamma rays are more penetrating than 2 MeV x-rays.
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