Children are more sensitive to radiation because cell division is happening actively in their body, and cancer is more likely to develop after an incubation period through the rest of their life which is longer than that of adult. In addition, because they are more likely to be exposed by diagnostic radiation due to illness and health checks even after they became adults, radiation protection should be actively carried out during the pediatric radiography examination.
In recent years, as the frequency of using diagnostic radiation equipment has been increasing globally, the number of various examination which use diagnostic radiation equipment is also increasing in medical institutions in the country and so is the amount of radiation exposure. As of 2011, the number of annual domestic medical radiation uses is 220 million cases and the amount of medical radiation exposure per capita is 1.4 mSv. It has increased 27.27% and 33.57% respectively, compared to that of 2009. The frequency of regular X-ray radiography is the highest and the number of chest radiography showed the highest frequency of 27.59%. In this study, we developed head and neck radiation protective gear that can be used during the chest radiography of the children(10 years old). This device can be easily worn and does not interfere with image interpretation. It consists of the first head and neck cover and the second esophagus cover that can defend the primary X-ray and scatter ray, 16.5 cm in height and 48.5 cm in length. In order to evaluate the usefulness of the device, we measured the difference of the amount of Entrance Surface Dose(ESD) and absorbed dose before and after wearing the protective gear, by using glass dosimeter and international standard pediatric phantom(10 years old). We also calculated the effective dose by employing PCXMC program, and indirectly evaluated the reduction rate by comparing Lifetime Attributable Risk of cancer incidence(LAR).
When the protective gear was used, the entrance surface dose (reduction rate) was decreased to 84.91% on average: the nasal cavity 0.60 μGy (72.12%), thyroid 1.52 μGy (95.31%), esophagus 9.19 μGy (75.60%). And also the depth dose (reduction rate) was decreased to 69.74% on average : the cervical spine 1.58 μGy (85.78%), salivary glands 1.03 μGy (81.00%), esophagus 3.52 μGy (59.68%), thyroid 2.29 μGy (68.12%) thoracic vertebrea 4.89 μGy (57.61%). This leads us to confirm the usability of the shielding gear. In addition, the effective dose was decreased by 0.95 μSv (10.05%) from 9.44 μSv to 8.50 μSv before and after wearing the device. And in the LAR evaluation, thyroid cancer was decreased to 0.16 male people (95.47%) and 0.88 female people (95.48%), and all cancers were found to be decreased to 0.14 male people (10.05%) and 0.25 female people (10.05%) per million capita(10 years old children). Even though diagnostic radiology examinations are necessary for diagnosis and treatment of diseases, if we consider the uniqueness of children, we should do our best to optimize medical radiation by actively utilizing such shielding device based on ALARA concept.