Radiation Dose to Technologists per Nuclear Medicine Examination and Estimation of Annual Dose

Abstract

Conventional diagnostic nuclear medicine applications have been continuously increasing in most nuclear medicine departments in Turkey, but to our knowledge no one has studied the doses to technologists who perform nuclear medicine procedures. Most nuclear medicine laboratories do not have separate control rooms for technologists, who are quite close to the patient during data acquisition. Technologists must therefore stay behind lead shields while performing their task if they are to reduce the radiation dose received. The aim of this study was to determine external radiation doses to technologists during nuclear medicine procedures with and without a lead shield. Another aim was to investigate the occupational annual external radiation doses to Turkish technologists. Methods: This study used a Geiger-Mü ller detector to measure dose rates to technologists at various distances from patients (0.25, 0.50, 1, and 2 m and behind a lead shield) and determined the average time spent by technologists at these distances. Deep-dose equivalents to technologists were obtained. The following conventional nuclear medicine procedures were considered: thyroid scintigraphy performed using 99m Tc pertechnetate, whole-body bone scanning performed using 99m Tc-methylene diphosphonate, myocardial perfusion scanning performed using 99m Tcmethoxyisobutyl isonitrile, and 201 Tl (thallous chloride) and renal scanning performed using 99m Tc-dimercaptosuccinic acid. Results: The measured deep-dose equivalent to technologists per procedure was within the range of 0.13 6 0.05 to 0.43 6 0.17 mSv using a lead shield and 0.21 6 0.07 to 1.01 6 0.46 mSv without a lead shield. Also, the annual individual dose to a technologist performing only a particular scintigraphic procedure throughout a year was estimated. Conclusion: For a total of 95 clinical cases (71 patients), effective external radiation doses to technologists were found to be within the permissible levels. This study showed that a 2-mm lead shield markedly reduced the external dose to technologists. The doses to technologists varied significantly for different diagnostic applications. Consequently, the estimated annual dose to a technologist performing only a particular scintigraphic procedure is very different from one type of procedure to another. The results of this study should help in determining the rotation time of technologists in different procedures and differences in their individual techniques.

Nuclear radiation dose to the surroundings from patients who are undergoing nuclear medicine examinations

“…The findings are in line with previous studies (Mettler et al 2009, Konishi et al 1994, Bayram et al 2011and Piwowarska-Bilska et al 2011 The radiation is most significant in the time immediately after injection. Our results reaffirm the conclusion from Konishi et al 1994 that "undue anxiety among hospital staff with regard to exposure to radioactive patients [and excreted urine from patients] must be placed in the proper perspective through education and training".…”

“…We used Bayram et als survey (Bayram et al 2011) as a methodological guide for measuring the radiation dose from patients. All measurements was obtained with a hand held dosimeter: RadEye B20 from Thermo Scientific.…”

“…The study of Konishi et al from 1994 (Konishi, Abe andKusama 1994) reported that significant exposure from patients to staff was in practice limited to the day of administration. More recently, Bayram et al (2011) measured the dose received by employees in a range of nuclear medicine examinations at specified distances. The authors conclude that there was a marked reduction of radiation dose using lead protection and keeping greater physical distance from the patient, and that this should be the guideline for staff at nuclear medicine departments.…”

Importance of Bladder Radioactivity for Radiation Safety in Nuclear Medicine

“…Radiation dose or dose rates per application and in total to staff within a time period such as daily, monthly or annually can be determined by two different methods (3,4,5,6,7,8). At first, it is calculated by measurements obtained at a fixed distance from the patient and some authors also take into consideration the time spent with the patient at a constant distance to calculate the amount of expected radiation exposure to technicians (4,5).…”

Dose rates in nuclear medicine and the effectiveness of lead aprons

“…A different study was conducted by Fog et al [11] using Monte Carlo techniques to simulate the effectiveness of a lead apron against 99m Tc and 18 F. This study found reasonable dose reductions when shielding against 99m Tc but minimal protection against the higher energies of 18 F. The study also reported varying degrees of dose escalation at small distances from behind a lead apron, although it was concluded that this would most likely be absorbed by the wearer's clothing. Other types of shielding that can be used include mobile shields, and their effectiveness was investigated by Bayram et al [12].…”