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Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Empowering the next generation: ANS’s newest book focuses on careers in nuclear energy
A new career guide for the nuclear energy industry is now available: The Nuclear Empowered Workforce by Earnestine Johnson. Drawing on more than 30 years of experience across 16 nuclear facilities, Johnson offers a practical, insightful look into some of the many career paths available in commercial nuclear power. To mark the release, Johnson sat down with Nuclear News for a wide-ranging conversation about her career, her motivation for writing the book, and her advice for the next generation of nuclear professionals.
When Johnson began her career at engineering services company Stone & Webster, she entered a field still reeling from the effects of the Three Mile Island incident in 1979, nearly 15 years earlier. Her hiring cohort was the first group of new engineering graduates the company had brought on since TMI, a reflection of the industry-wide pause in nuclear construction. Her first long-term assignment—at the Millstone site in Waterford, Conn., helping resolve design issues stemming from TMI—marked the beginning of a long and varied career that spanned positions across the country.
H. L. Atkins, P. Richards, L. Schiffer
Nuclear Technology | Volume 2 | Number 1 | February 1966 | Pages 27-32
Technical Paper | doi.org/10.13182/NT66-A27563
Articles are hosted by Taylor and Francis Online.
The physical characteristics of 99mTc, including a short half-life of 6 h and a nearly monochromatic gamma emission of 140 keV, make it an excellent agent for scintillation scanning. Because of the short half-life and absence of significant beta emission, large amounts of activity may be used, the radiation dose to the patient being very low. Possibilities thus exist for greater resolution through optimal design of collimation and for more rapid scans because of better counting statistics. A colloid of this isotope has been prepared by passing hydrogen sulfide through a solution of 1 N HCl containing pertechnetate. This colloid, with an average blood disappearance half-time of 2.5 min, has proved useful in performing scintillation scans of liver, spleen, and bone marrow. A specially designed collimator of 721 holes has provided resolution comparable to the commercially available 31-hole collimator but with a sensitivity considerably greater than the 19-hole collimator. Maximum count rates over the liver are 75 000 to 100 000 counts/min following administration of 10 mCi of the colloid intravenously. Modification of a commercially available scanner has been made by bypassing the contrast enhancement circuits and doubling the speed in order to exploit the high count rates. Count rates over bone marrow are maximally 1/10 to 1/15 of the liver count, and spleen count rates fall in between liver and bone-marrow rates. Estimation of spleen size and extent of functioning marrow are possible in addition to detection of space-occupying disease of the liver.
