Dr Peck focuses on the relevant and important issue of dosage of radiation delivered to breast tissue at mammography. At the time our article was prepared, our estimates seemed to reflect the state of the art. With intervening changing technology and improved films and filters, Dr Peck is correct to note that detailed mammography is possible with a markedly reduced radiation exposure (mean midbreast dose of 0.08 rads for two views1).
However, since glandular epithelial tissue begins 0.5 cm from the skin surface, the midbreast dose measured 3 cm from the skin surface may not reflect the maximal radiation exposure of tissues at risk for carcinogenic effects. Using dose depth curves from phantoms selected to match the radiation interaction properties of 50% adipose/50% mammary gland,1 a skin exposure of 0.79 rads resulted in exposures to mammary gland tissues 0.5 cm from the skin ranging from 0.96 to 1.36