Panel Discussion: Pulmonary Embolism Imaging and Outcomes

Abstract

1313 are accurate, they amount to a less than 1% increased incidence of cancer mortality for the highest risk group (i.e., young women) [13]. The population undergoing pulmonary CTA is older and at even lower risk of carcinogenesis due to radiation. For example, in our study [7], the mean age of the patients undergoing pulmonary CTA was 63 years, a group for whom additional cancer mortality is in the range of one tenth of 1% [13]. Nonionic iodinated contrast material is also very low risk because there is a less than 1% incidence of reactions [14], and reactions that do occur are usually mild, most frequently hives. Barbosa—The answer to this broad and important question necessitates a thoughtful appreciation of quantitative risks, as follows. Radiation-related risks of pulmonary CTA are exclusively stochastic effects, mostly cancer induction, given that current doses of less than 10 mSv are well below the threshold for deterministic effects, which starts at 2000 mSv (2 Gy) [15, 16]. There is ample literature regarding radiation carcinogenesis, particularly at moderate or high exposures (> 100 mSv). However, it must be emphasized that the existing data for lower exposures in the range of pulmonary CTA are far less reliable, obtained from linear regression models extrapolating from much higher exposures observed in nuclear accidents and detonations. Moreover, it is difficult and costly to perform high-quality studies to show quantitative causal relationships between low-dose exposures and carcinogenesis, given the long latency of radiation-induced cancers and also the much greater baseline prevalence of cancer. The estimated additional relative risk of all cancers from the International Commission of Radiologic Protection published in 2007 [15] is 0.005% per millisievert of dose. This is a very small number in comparison with the baseline incidence of all cancers, which is orders of magnitude higher. TherePanel Discussion: Pulmonary Embolism Imaging and Outcomes