This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
The radiation tolerance of the whole liver as – 
Select and explain. 
A. 15 Gy, B. 30 Gy, C. 40 Gy, D. 45 Gy
C: 40 Gy
Answer: C: 40 Gy 
Explanation: Maximum tolerance dose (TD 50/5) for whole liver is 40 Gy. For 2/3 volume of liver TD 50/5 is 45 Gy and for 1/3 volume of liver TD 50/5 is 55 Gy. (For details, read the topic "volume factors in radiation toxicity", of this chapter).