Radiation Safety and Dosimetry

A 28-year-old woman presents to the emergency department with acute right upper quadrant pain and fever (38.5°C). Ultrasound of the abdomen is inconclusive. The radiologist recommends a CT abdomen with IV contrast to rule out acute cholecystitis and possible cholangitis. The patient is 8 weeks pregnant (confirmed by urine beta-hCG). What is the most appropriate next step regarding imaging?

A 62-year-old man with a history of multiple myeloma undergoes a staging PET-CT scan (18F-FDG PET combined with diagnostic CT) for assessment of disease burden. The patient's weight is 70 kg. The radiologist calculates the effective dose from the combined study to be approximately 25 mSv. The patient asks about the cancer risk from this single imaging study. Which statement best reflects the radiation risk in this clinical context?

A 32-year-old woman presents to the emergency department with acute abdominal pain and vaginal bleeding. She is 8 weeks pregnant (confirmed by urine β-hCG). Clinical examination suggests possible ectopic pregnancy. The radiologist proposes a transvaginal ultrasound to confirm the diagnosis. The patient is anxious about radiation exposure to the fetus. What is the most appropriate counseling regarding radiation risk in this scenario?

A 58-year-old man with a history of recurrent urinary tract infections undergoes a CT abdomen and pelvis for evaluation of hydronephrosis. The radiologist notes that the patient has received 4 similar CT scans over the past 2 years for similar indications. The cumulative effective dose from these 4 scans is estimated at 48 mSv. The patient asks about the cancer risk from this cumulative radiation exposure. What is the most accurate statement regarding his risk?

What is the annual occupational dose limit for radiation workers in India as per the Atomic Energy Regulatory Board (AERB) guidelines?