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Updated: Feb 22, 2026

Clinical Imaging of Microwave Mammography
Published on: November 14, 2025
Appropriate imaging utilization in Japan: a survey of accredited radiology training hospitals
Kanako K Kumamaru1, Sadayuki Murayama2, Yasuyuki Yamashita3
1Department of Radiology, Graduate School of Medicine, Juntendo University, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. k-kumamaru@juntendo.ac.jp.
Purpose:
To survey whether imaging is being performed appropriately in Japan, and to survey whether radiologists intervene to ensure imaging requests are appropriate.
Methods:
An online survey was sent to radiologists at accredited radiology training hospitals. The survey included the radiologists' perspectives on whether imaging is performed appropriately at their institutions and whether they intervene if the indication for imaging is inappropriate/ambiguous.
Results:
The response rate was 87.3% (165/189). We observed marked variability in the frequencies that imaging not recommended by the guidelines was performed among modalities and/or body parts; the responses "very frequently/frequently performed" were more common for breast cancer related imaging examinations and for head CT/MRI. The respondents frequently reported that inappropriate/ambiguous indications included requests to expand the craniocaudal range or to perform whole-body imaging. In 80% of the hospitals (132/165), radiologists contacted the physicians who requested unrecommended examinations; the number of CT and MRI examinations that full-time radiologists need to interpret in a half-day session was significantly smaller at these hospitals (median 18 vs 24, P = 0.032).
Conclusion:
We conducted a survey to investigate appropriate imaging utilization in Japan. At the hospitals with numerous examinations to interpret, full-time radiologists may find it difficult to ensure that examinations are ordered appropriately.
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