Reply: Does Direct Transcatheter Aortic Valve Replacement Increase the Risk of Cerebral Embolization?

dosimetry for radiodiagnostics (2). It has been used for personal dosimetry (as a replacement for film badges) and medical dosimetry for both radiotherapy and radiodiagnostics (2,3). The dosimeters (nanoDot, Landauer, Glenwood, Illinois) used in our study are OSL based, small (1 1 0.2 cm), environmentally stable, and highly accurate and precise within the exposures measured in the study (3). Additionally, placing them under the XPF attenuating cap (BLOXR Corp., Salt Lake City, Utah) made them imperceptible to the research subjects and enabled comparative data assessment between cranial locations. Although not a focus of this paper, the biological effects of long-term, low-dose radiation exposure including the stochastic and dose-dependent deterministic effects on health care workers are well established. In fact, Andreassi et al. (4) recently reported that workers exposed to high medical radiation in the cardiac catheterization laboratory had increased left-sided carotid intima-media thickness (CIMT) and reduced leukocyte telomere length. The presence of a specific polymorphism of the DNA repair gene XRCC3 Thr241Met, associated with increased chromosomal DNA damage in workers occupationally exposed to long-term ionizing radiation, was also found to be more prevalent in highexposure workers and associated with increased CIMT (4). Although the risk of occupational radiation–induced brain malignancies has not been determined, this study (complete lifetime dosimetry reconstruction: occupational exposure, 12.6 8.6 years; dose, 21.1 26.3 mSv) suggests that adverse vascular and subcellular effects exist for the left side of the head and neck region of operators at case volumes that are within routine practice and not 2.5 million. The secondary objective of our study was to determine whether a light-weight cap (nonlead based) could help attenuate the cranial radiation exposure to near ambient levels. The studied cap met those objectives, and its use would be consistent with the fundamental radiation safety principle of keeping medical radiation “as low as reasonably achievable.”