Suboptimal awareness of radiologic dose among patients undergoing cardiac stress scintigraphy.

OBJECTIVE: Patients undergoing radiologic and nuclear medicine examination often receive little, if any, information related to the radiologic dose and consequent potential long-term cancer risk. This "economical with the truth" communication may violate basic patients' rights. We assessed the information perceived by patients on the radiation dose exposure during nuclear medicine examinations.
METHODS: We recruited 109 consecutive patients (66 male; aged 66 +/- 10 years) who were referred to the Nuclear Medicine laboratory of Sant'Orsola-Malpighi Hospital (Bologna University, Bologna, Italy) for a cardiac rest-stress technetium-99m sestamibi scan. This scan gives an effective dose of approximately 10 mSv, corresponding to a dose equivalent of 500 chest x-rays (European Commission Medical Imaging Guidelines 2001) and an estimated extra lifetime attributable risk of 1 cancer in 1,000 exposed subjects (Biological Effects of Ionizing Radiation VII Committee 2005).
RESULTS: Radiation dose exposure was correctly identified by 21% of patients, with the remaining 79% underestimating the exposure by at least 500 times, considered to be zero by 11%, one-half of a chest x-ray by 23%, 1 chest x-ray by 35%, and "don't know" by 10%. The long-term cancer risk was correctly estimated by 27% of patients, with the remaining substantially underestimating the risk, considered to be "zero" by 30%, 1 in 1 million by 19%, 1 in 100,000 by 9%, and "don't know" by 10%.
CONCLUSION: Patients undergoing common cardiac stress scintigraphy examinations involving significant radiation exposure have little or no awareness about nuclear medicine dose (and corresponding risk). This ineffective communication poses significant ethical concerns and possible vulnerability to legal suits against practitioners and prescribers, especially in case of inappropriate examinations.