This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Care of Patients During Radiotherapy, Subject name: Radiology
Maximum permissible radiation dose in pregnancy is: 
Select and explain. 
A. 0.5 rad., B. 1.0 rad., C. 1.5 rad., D. 3.0 rad.
A: 0.5 rad.
Answer: A: 0.5 rad. 
Explanation: Ans. is 'a' i.e. 0.5 radRef. Diagnostic radiology and Imaging by K. Subbarao, Jaypee publication, Christensen's physics of diagnostic radiologyMaximum permissible radiation doseIs that dose which if received each year for a 50 year working lifetime would not be expected to produce any harmful effect?The maximum permissible dose for a pregnant woman is 0.5 rads in gestation periodAlso knowThe gestation period when the fetus is most sensitive to the effect of radiation -8-15 weeks of gestationThe'10 day rule'This rule advices that any x-ray examination involving the abdomen of a women of child -bearing age should be carried out within 10 days of the onset of menstruation.