I have over 20 years of experience in medical physics and medical radiation protection. I hold a doctorate in nuclear engineering, two board certifications in medical physics from the American Board of Radiology, and am a clinical associate professor of radiology at the University of California, Davis. I teach medical physics to radiology resident physicians and am a co-author of a textbook on the physics of medical imaging. The ICRP’s changes, every ten years or so, to terminology and to the system of protection itself can be disruptive to national regulatory systems and to the field of radiation protection. For example, major changes render textbook material on radiation safety instantly obsolete. Textbooks and teaching must describe current national regulations, which are based on old ICRP terminology and systems of protection, as well as the ICRP’s latest system. This complicates the writing of textbooks and teaching of radiation protection, because both the existing system and the proposed system must be taught. Therefore, changes should be made to the ICRP’s terminology and system of protection if and only if they add significant value. Two examples of unnecessary changes in the 2005 draft recommendations are: 1. The term “tissue reactions.” In 1977, the ICRP used the term “non-stochastic effects”, then in 1990, “deterministic effects”, and now is proposing “tissue reactions”. Will there be yet another term in the year 2015? 2. The system of both dose constraints and dose limits for workers is awkward and unnecessary. Most workers receive their occupational doses from a single employer. Page 1 of the draft ICRP recommendations states, “It (the Commission) also recognizes the need for stability in regulatory systems at a time when there is no major problem identified with the practical use of the present system in normal situations.” The system of both constraints and limits for occupational doses and unnecessary terminology changes are contrary to this statement. I recommend: 1. Continue using the term “deterministic effects” instead of “tissue reactions”. 2. Eliminate the use of dose constraints for workers, and have only dose limits, with the provision that, if a worker receives occupation dose from more than one employer, the sum of the doses must not exceed the limits. Thank you for permitting me to comment on the draft recommendations.