DR.TSUBOKURA'S RADIATION LECTURE VOL.156

Author: Masaharu Tsubokura M.D., PhD.

Editor: Yudai Kaneda

311　 High Radiation Levels in Japanese Healthcare

January 16, 2021

We are surrounded by a variety of natural radioactive substances, from which we are exposed to a certain amount of radiation on a daily basis.

　The radiation exposure varies by location and country, but the total amount of internal and external natural radiation we receive in Japan tends to be 2.1 millisieverts per year, which is slightly lower than the global average of 2.4 millisieverts.

　On the other hand, the amount of radiation received during medical procedures for diagnosis and treatment in Japan is known to be high by global standards. Although it varies greatly from person to person, on average, people in Japan receive about twice as much radiation from radiological examinations as they do from the natural environment.

Radiological examinations also cover external and internal radiation exposure.

General X-ray examinations used for health checkups, CT examinations that look at cross-sections of the body, fluoroscopy (examination of the inside of the body in real time using continuous radiation) such as barium examinations of the stomach, X-ray examinations at the dentist, and mammography for breasts are all examinations related to external radiation exposure.

In contrast, the nuclear medicine test (scintigraphy) to examine the function of organs such as the heart and bones by injecting drugs that emit radiation inside the body and detect the radiation coming out of the body as well as the PET scan to examine the size of tumors and inflammation lesions are examinations related to internal radiation exposure.

312　 Thyroid Hormones Keep You Healthy

January 30, 2021

The thyroid gland is a small organ of about 10 to 20 grams located slightly below the middle of the neck (below the throat). It looks like a butterfly with its wings spread out, and it surrounds trachea, which is the air pathway. Its size varies from person to person, so if you have a large one, you can touch it from the surface of your body.

　The thyroid gland produces thyroid hormones from iodine, which is contained in food and other substances and is always essential for our daily lives.

　Thyroid hormones play an important role in promoting the growth and development of a child’s body and brain by maintaining energy metabolism and protein synthesis, as well as producing heat and sweat and actively moving muscles and digestive tracts.

　Hormone levels that are too high or too low can each cause problems.

　A decrease in the secretion of thyroid hormones can lead to a condition called hypothyroidism (Hashimoto’s disease), which causes fatigue and swelling, whereas an increase in the secretion of hormones can lead to a condition called hyperthyroidism (Basedow’s disease), which causes irritability, palpitations, shortness of breath, and tremors in one’s hands.

　We make and use hormones every day, and it is very important to maintain the balance of the hormones in our daily lives.

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The Japanese version of the manuscript was originally published in Fukushima Minyu, a local newspaper in Fukushima prefecture, Japan, on 16 and 30 January 2021 was reproduced for MRIC Global under the author's permission.