Experts plan to track radiation doses from medical checks

July 09, 2012

By YURI OIWA/ Staff Writer

Concerned about an increase in radiation exposure at hospitals, a group of researchers plans to set up a system to track patients’ cumulative radiation doses and protect children from potential harm.

The Japan Network for Research and Information on Medical Exposures (J-RIME) will compile proposals within two years and lobby relevant government ministries and agencies.

“We want to create a system in which patients can gain the utmost benefits from medical examinations and treatments that use radiation,” said Yoshiharu Yonekura, who leads J-RIME and president of the National Institute of Radiological Sciences.

According to the institute, a Japanese patient is exposed to an average 3.8 millisieverts of radiation a year from medical checks, excluding treatment. That is twice the average of industrialized countries and nearly quadruple the permissible level set for an average Japanese, excluding doses from examinations and treatment.

J-RIME includes 12 organizations of radiologists and radiological technicians, including the Japan Radiological Society, the Japanese Society for Therapeutic Radiology and Oncology and the Japanese Society of Pediatric Radiology.

It will begin a study to determine the patients’ doses from computerized tomography (CT) scans, positron-emission tomography (PET) scans and other medical procedures.

A PET scan is an imaging procedure used to identify tumors by injecting a patient with a medical agent containing radioactive materials.

The group plans to keep records for individual patients on the types of scans and the accumulated radiation doses they received.

J-RIME is also expected to come up with safety limits for doses from CT scans for children, as well as measures to protect them from exposure to high radiation levels.

In a medical journal published in June, a British team of researchers reported a small increase in the risk of leukemia and brain tumors from CT scans. The team studied about 180,000 children and young adults, and found that one case of leukemia and one brain tumor would occur after the first CT scan for every 10,000 CT examinations performed on children under 11 years old.

The widespread use of CT scans in recent years has been a significant factor behind the doubling of people's radiation does over the past two decades, according to the U.N. Scientific Committee on the Effects of Atomic Radiation.

A patient is exposed to 5 to 30 millisieverts on average per CT scan, more than 10 times higher than that from a conventional X-ray procedure.

Japan by far has the largest number of CT scanners among advanced countries.

The International Atomic Energy Agency and the World Health Organization issued statements in April calling for the establishment of rules to keep track of cumulative radiation doses of individual patients.

By YURI OIWA/ Staff Writer
  • 1
submit to reddit
The Asahi Shimbun

The Asahi Shimbun

Toggle
  • The Asahi Shimbun