Question:medium
The dose of radiation required for development of the haematological (bone marrow) syndrome is?
The dose of radiation required for development of the haematological (bone marrow) syndrome is?
Show Hint
Bone marrow stem cells are highly radiosensitive, so this syndrome needs the lowest dose.
Updated On: Jun 24, 2026
- 2 to 5 Gy
- 10 Gy
- 100 Gy
- 200 Gy
Show Solution
The Correct Option is A
Solution and Explanation
Order the acute radiation syndromes by the dose that triggers them, because the question is really asking for the lowest-dose syndrome. The sequence with rising whole-body exposure is bone marrow first, then gut, then brain.
The bone marrow (haematopoietic) syndrome is the earliest to appear because haematopoietic stem cells are among the most radiosensitive cells in the body. A whole-body dose of about 2 to 5 Gy is enough to knock out marrow function, after which the falling counts produce anaemia, immunosuppression with infection, and bleeding tendency over the following weeks.
Larger doses are needed for the other patterns: the gastrointestinal syndrome from denudation of the gut epithelium needs higher exposure, and the catastrophic central nervous system syndrome requires extremely high doses. Among the four options offered, only the 2 to 5 Gy band matches the marrow threshold; the others are far too high.
So the haematological syndrome corresponds to the lowest dose listed.
\[\boxed{\text{2 to 5 Gy}}\]
The bone marrow (haematopoietic) syndrome is the earliest to appear because haematopoietic stem cells are among the most radiosensitive cells in the body. A whole-body dose of about 2 to 5 Gy is enough to knock out marrow function, after which the falling counts produce anaemia, immunosuppression with infection, and bleeding tendency over the following weeks.
Larger doses are needed for the other patterns: the gastrointestinal syndrome from denudation of the gut epithelium needs higher exposure, and the catastrophic central nervous system syndrome requires extremely high doses. Among the four options offered, only the 2 to 5 Gy band matches the marrow threshold; the others are far too high.
So the haematological syndrome corresponds to the lowest dose listed.
\[\boxed{\text{2 to 5 Gy}}\]
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