A model for development of fingertip radiation exposure and for the risk of musculoskeletal disorders based on upper limb anthropometry, grip strength and workstation design

Sandra Suzanne Cole, Purdue University

Abstract

In the United States (U.S.) over the past 30 years, the number of medical procedures using radiopharmaceuticals has increased 500% along with a similar increase in the per capita effective dose. The Bureau of Labor statistics (BLS) reported from 1999 to 2010, that the numbers of nuclear medicine technologists have increased by nearly 200%. Therefore, if the patient dose has increased, there is potential for the dose from radiation exposure to workers in the nuclear pharmacy to increase. The dose that is of particular concern is the dose to the extremities, especially the fingertips. In addition to the risk of radiation exposure, workers in nuclear pharmacy are at risk for musculoskeletal disorders, especially to the upper limbs and low back because of the design of nuclear pharmacy workstations. The first major goal of this study was to investigate the interaction of the workstation design, radiation exposure, risk of musculoskeletal disorders, and individual anthropometry using the technique of video exposure monitoring (VEM) with a real-time extremity dosimeter. Shielding and good work practices are designed to limit the annual radiation exposure to the extremities to less than 500 millisievert (mSv) per the National Commission on Radiation Protection (NCRP). However, individuals in nuclear pharmacy laboratories do not always follow these practices. Because of this, the second major goal of this study was to identify specific work practices in the nuclear pharmacy laboratories using the principle of "As low as reasonably achievable" (ALARA) that can cause increased radiation exposure to the extremities. The third major goal was to define a potential relationship between anthropometric variations and radiation exposure to radiopharmaceuticals and to identify worker tasks that can cause musculoskeletal stress to the body, thereby affecting worker efficiency and productivity. The fourth goal was to recommend a new workstation design that could reduce radiation exposure and reduce the risk of musculoskeletal disorders. The radiation exposure assessment in Phase 1 of this study showed that using optimal practices minimizes dose but it is not 0. The greatest exposure to the extremities using optimal work practices is the capping and recapping of the needle and miscellaneous activities. Using optimal work practices versus non-optimal work practices was found to take up to twice the amount of time on average to perform the entire protocol for inexperienced workers. However, the integrated exposure to radiation was using non-optimal work practices was approximately 7 times the exposure of when using optimal work practices. When the job was broken down into tasks, there were four distinct elements (practices) per job cycle. The optimal versus non-optimal work practices shows that the time to perform each task element was longer by factors of 1.3, 1.8, 1.8, and 2.1 respectively. The exposure to radiation using non-optimal work practices was more than when using optimal work practices for Task element 1, 2, 3, and 4 by factors of 5.7, 5.0, 16.9, and 5.0, respectively. This indicates that optimal work practices should be a part of the training of workers in the nuclear pharmacy. Aspects of the current workstation are designed to minimize radiation exposure, however, these design aspects that reduce radiation exposure may increase the risk of musculoskeletal disorders. However, designing purely for minimization of musculoskeletal disorders may put the worker at risk of exposures beyond the occupational limit to the extremities of 500 mSv (50 rem) in a year. This study concluded from the analysis of the dimensions of the L-block relative to anthropometry, the radiation exposure assessment, and ergonomic assessment that the current L-block design may influence excess radiation exposure and the risk of musculoskeletal disorders. Therefore, a redesigned workstation that uses anthropometry to account for individual variations is warranted. Based on the results from this study, the new workstation should still be in the form of an L-Block but be adjustable in height and width so that it fits 90% of the United States work population. A redesigned workstation has the potential to reduce radiation exposure and lessen the risk of musculoskeletal disorders. (Abstract shortened by UMI.)

Degree

Ph.D.

Advisors

McGlothlin, Purdue University.

Subject Area

Occupational health|Health sciences

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