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KMID : 0861420120160010080
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Korean Journal of Nuclear Medicine Technology
2012 Volume.16 No. 1 p.80 ~ p.85
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The Study of Radiation Reducing Method during Injection Radiopharmaceuticals
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Cho Seok-Won
Chung Seok
Park Jun-Young
Oh Shin-Hyun
Namkoong Hyuk
Oh Ki-Beak
Kim Jae-Sam
Lee Chang-Ho
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Abstract
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Purpose: The whole body bone scan is an examination that visualizing physiological change of bones and using bone-congenial radiopharmaceutical. The patients are intravenous injected radiopharmaceutical which labeled with radioactive isotope (99mTc) emitting 140 keV gammarays and scanned after injection. The 3 principles of radiation protection from external exposureare time, distance and shielding. On the 3 principles of radiation protection basis, radiopharmaceutical might just as well be injected rapidly for reducing radiation because it might be the unopened radiation source. However the radiopharmaceuticals are injected into patient directly and there is a limitation of distance control. This study confirmed the change of radiation exposure as change of distance from radiopharmaceutical and observed the change of radiation exposure afte rsetting a shelter for help to control radio-technician’s exposure.
Materials & Methods: For calculate the average of injection time, the trained injector measured the injection time for 50 times and calculated the average (2 minutes). We made a source as filled the 99mTc-HDP 925 MBq 0.2 mL in a 1 mL syringe and measured the radiation exposure from 50 cm,100 cm,150 cm and 200 cm by using Geiger-Mueller counter (FH-40, Thermo Scientific, USA). Then we settled a lead shielding (lead equivalent 6 mm) from the source 25 cm distance and measured the radiation exposure from 50 cm distance. For verify the reproducibility, the measurement was done among 20 times. The correlation between before and after shielding was verified by using SPSS (ver. 18) as paired t-test.
Results: The radiation doses according to distance during 2 minutes from the source without shielding were 1.986±0.052 μ Sv in 50 cm, 0.515±0.022 μ Sv in 100 cm, 0.251±0.012 μ Sv in 150 cm, 0.148±0.006 μ Sv in 200 cm. After setting the shielding, the radiation dose was 0.035±0.003 μ Sv. Therefore, there was a statistical significant difference between the radiation doses with shielding and without shielding (p<0.001).
Conclusion: Because the great importance of whole body bone scan in the nuclear medicine, we should make an effort to reduce radiation exposure during radiopharmaceutical injections by referring the principles of radiation protection from external exposure. However there is a limitation of distance for direct injection and time for patients having attenuated tubules. We confirmed the reduction of radiation exposure by increasing distance. In case of setting shield from source 25 cm away, we confirmed reducing of radiation exposure. Therefore it would be better for reducing of radiation exposure to using shield during radiopharmaceutical injection.
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KEYWORD
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Radioactive Isotope, Shied, Dose
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