Final answer:
The imaging system that requires the lowest patient dose is digital photospot.
Step-by-step explanation:
The imaging system that requires the lowest patient dose is digital photospot.
The information provided states that medical doses of radiation are limited and diagnostic doses have been further lowered with improved techniques. In the table presented, it lists radioisotopes used in medical imaging, implying their use in diagnosing medical conditions. It is mentioned that medical images with radiopharmaceuticals give doses ranging from 1 to 5 mSv, usually localized. However, the photospot/digital imaging technique does not involve the use of radioisotopes or radiopharmaceuticals, making it a safer option with a lower patient dose.