A distance-assisted training program for nuclear medicine technologists

We have developed training materials for nuclear medicine technologists to be used in distance-assisted training programs. We have completed our first pilot project in Asia and report that there will be nearly 500 students around the world, in Asia, Africa, Central America and South America, using our materials during the coming year.     

Measuring and minimizing the radiation dose to nuclear medicine technologists

OBJECTIVE: Nuclear medicine technologists rely on a single dosimeter to measure their work-related dose. Estimates of whole-body effective dose are based on the assumptions that the radiation is incident from the front and in a uniform beam. We sought to investigate these assumptions and also to quantify doses associated with different activities. METHODS: A single technologist wore 3 electronic dosimeters for 3 mo, at the front waist, the back waist, and the front collar. The technologist also recorded her activities throughout the day. RESULTS: We found that the assumption of an anterior beam held about two thirds of the time, breaking down only when the technologist was receiving lower doses. Overall, the average whole-body dose was estimated correctly by assuming an anterior beam. We also found that irradiation was uniform (i.e., waist and collar badges gave equivalent readings) except when the technologist was performing injections. Then, the collar readings were 1.7 times the waist readings. Finally, average doses were measured for different types of activities. Performing injections registered a dose rate of approximately 2 microSv/h. Doses received while scanning ranged from 0.2 to 2 microSv/h. The average dose for a scan depended not only on the administered activity and isotope but also on the amount of patient contact required. Even for high activities, such as patients who had already received therapy, the dose to the technologist was low for patients requiring little assistance. CONCLUSION: The assumption of anterior irradiation correctly estimates whole-body effective dose. The assumption of a uniform beam is good except when injections are being performed, when the upper torso receives a much higher dose than the waist. Overall, doses to the technologist were found to be 5.4 microSv/d for scanning and 12 microSv/d for injections. These correspond to 1.4 mSv/y and 3.2 mSv/y, respectively, which are comparable to naturally occurring radiation levels and are much lower than regulatory limits. However, if the dose to a particular technologist needs to be minimized (e.g., for a pregnant worker), the most effective strategy is for the technologist to be assigned patients requiring little contact or assistance and, in particular, to avoid administering injections.     

Radiation safety for radiologic technologists

Radiologic technologists and ancillary staff who work with or near ionizing radiation face possible short- and long-term effects of occupational radiation exposure. Further, radiologic technologists must minimize unnecessary exposure that risks the patient's safety, while achieving the best possible image or outcome. This article reviews occupational dose limits, dose calculation, devices used to measure exposure, and safety best practices that can help technologists keep radiation exposure "as low as reasonably achievable" for them and their patients. The article also discusses the appropriate use of mounted and mobile equipment, personal protective equipment, and safety features on imaging equipment to minimize unnecessary radiation exposure.     

National survey of imaging technologists in nuclear medicine 1998/99

This survey investigated the nature of imaging staff and the distribution and structure of nuclear medicine departments in the UK. Total numbers of cameras and average per department were lower than in 1989/90 but higher than the 1992/93 survey. Total whole time equivalents, average per department and average per camera had increased. Excluding the Isle of Man, Wales had the lowest population per camera and Northern Ireland the highest. This survey identified 237 departments (90 independent, 116 integrated and 31 satellite), radiographers being the chief technologists in 64% and MTOs in 36%. Over half had one single-headed camera but one third had dual- or triple-headed cameras. Chief technologist grades ranged from Basic to Superintendent II and MTO3 to MTO5. The most common grades for other staff were Senior II or MTO3. Of the 786 technologists who provided details, 68% had initially trained as radiographers. Specific nuclear medicine qualifications were held by 67% of all technologists. In 52% of departments at least one member of staff rotated between nuclear medicine and another department or hospitals and 25% had no full-time staff. Survey returns revealed that, although 84% of imaging technologists often or occasionally attended conferences, 5% never attended.     

X-ray imaging physics for nuclear medicine technologists. Part 2: X-ray interactions and image formation

The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. In part 1, the production and characteristics of x-rays were reviewed. In this article, the principles of x-ray interactions and image formation are discussed, in preparation for a general review of CT (part 3) and a more detailed investigation of PET/CT scanners in part 4.     

X-ray imaging physics for nuclear medicine technologists. Part 1: Basic principles of x-ray production

The purpose is to review in a 4-part series: (i) the basic principles of x-ray production, (ii) x-ray interactions and data capture/conversion, (iii) acquisition/creation of the CT image, and (iv) operational details of a modern multislice CT scanner integrated with a PET scanner. Advances in PET technology have lead to widespread applications in diagnostic imaging and oncologic staging of disease. Combined PET/CT scanners provide the high-resolution anatomic imaging capability of CT with the metabolic and physiologic information by PET, to offer a significant increase in information content useful for the diagnostician and radiation oncologist, neurosurgeon, or other physician needing both anatomic detail and knowledge of disease extent. Nuclear medicine technologists at the forefront of PET should therefore have a good understanding of x-ray imaging physics and basic CT scanner operation, as covered by this 4-part series. After reading the first article on x-ray production, the nuclear medicine technologist will be familiar with (a) the physical characteristics of x-rays relative to other electromagnetic radiations, including gamma-rays in terms of energy, wavelength, and frequency; (b) methods of x-ray production and the characteristics of the output x-ray spectrum; (c) components necessary to produce x-rays, including the x-ray tube/x-ray generator and the parameters that control x-ray quality (energy) and quantity; (d) x-ray production limitations caused by heating and the impact on image acquisition and clinical throughput; and (e) a glossary of terms to assist in the understanding of this information.     

Radiation dose to PET technologists and strategies to lower occupational exposure

OBJECTIVE: The use of PET in Australia has grown rapidly. We conducted a prospective study of the radiation exposure of technologists working in PET and evaluated the occupational radiation dose after implementation of strategies to lower exposure. METHODS: Radiation doses measured by thermoluminescent dosimeters over a 2-y period were reviewed both for technologists working in PET and for technologists working in general nuclear medicine in a busy academic nuclear medicine department. The separate components of the procedures for dose administration and patient monitoring were assessed to identify the areas contributing the most to the dose received. The impact on dose of implementing portable 511-keV syringe shields (primary shields) and larger trolley-mounted shields (secondary shields) was also compared with initial results using no shield. RESULTS: We found that the radiation exposure of PET technologists was higher than that of technologists performing general nuclear medicine studies, with doses averaging 771 +/- 147 and 524 +/- 123 microSv per quarter, respectively (P = 0.01). The estimated dose per PET procedure was 4.1 microSv (11 nSv/MBq). Injection of 18F-FDG contributed the most to radiation exposure. The 511-keV syringe shield reduced the average dose per injection from 2.5 to 1.4 microSv (P < 0.001). For the longer period of dose transportation and injection, the additional use of the secondary shield resulted in a significantly lower dose of radiation than did use of the primary shield alone or no shield (1.9 vs. 3.6 microSv [P = 0.01] and 3.4 microSv [P = 0.03], respectively). CONCLUSION: The radiation doses currently received by technologists working in PET are within accepted occupational health guidelines, but improved shielding can further reduce the dose.