PACS in Japan; the Strong and the Weak
Hiromu Nishitani
Department of Radiology, Tokushima University Hospital,
770-8503, Tokushima, Japan
Objective
This is to introduce strong and weak aspects of PACS in Japan.
Social security policies in Japan (1)
The social security system in Japan has been the universal medical insurance and pension system covering all the citizens for the entire nation. The system has worked well for about 30 years under the directorship of the Japanese Ministry of Health and Welfare.
The rate of progress of fewer children and an aging population in Japan is at a speed unprecedented in other nations. The recent report from the Ministry of Health and Welfare revealed that the average life span in 1997 is 83.8 years for women and 77.2 years for men. Both are the longest average life span among the published data in the world. The population age 65 and older in 1995 was 14.8%; it is predicted that it will be 24.1% in 2015. At the same time, the total fertility rate (which indicates the number of children borne to a woman throughout her lifetime) had fallen to 1.43 in 1995. In the future, the labor force is expected to shrink. Japanese government started to consider that the burden of whatever scale the future of social security takes, may likely become a limiting factor in maintaining an energetic society and economy. Based on the situation of economy in Japan, strong pressure for deduction of medical care cost has begun. The government has been struggling to reform the social security system. It is becoming more and more difficult to build an expensive PACS system. Movements for de-regulation from the governmental control are on the way, but slow. Hospitals have to build their own PACS system with own risks and with some amount of regulations. These factors are influencing on the Strong and the Weak aspects of PACS in Japan.
Acceptance of DICOM 3.0
According to yearly reports on a monthly journal "Shin Iryo", DICOM 3.0 has been accepted with steady increase in Japan. DICOM 3.0 standard was installed at 13 hospitals in 1996, 55 hospitals in 1997, and 122 hospitals in 1998. At present, the ratio of DICOM 3.0 in image systems is still low as a whole. This is due to image systems pre-DICOM 3.0 era still active, but most new image systems have been installed using DICOM 3.0 as the communication standard. DICOM 3.0 is now the defacto standard.
"The common standard for electric storage of medical image files"
The electric storage of medical images instead of storing films has been approved legally since 1994. But it was restricted to an approved system that conforms to "the common standard for electric storage of medical image files" with the reversible compression of images. The efforts to conform to DICOM 3.0 were made, and the second standard applicable to DICOM 3.0 is now in use. This standard was originally based on the concept of "Image Save & Carry"(IS&C) and for the off-line usage mainly with the magneto-optical disk system. A draft for the secure on-line storage (Ver. 0.8) was published in April 1998(2), and is now under evaluation for approval. Off-line storage was with limited value for the usage in a large hospital. It took more than 4 years, and too late. This could be one of reasons why there are almost no film-less hospitals in Japan, although efforts to establish PACS started early in Japan. The main reason for delay was the safety or security problem.
CRT diagnosis
CRT Diagnosis is mandatory in PACS. The committee in the Japan Radiological Society evaluated CRT diagnosis. The results showed that there are no statistically significant differences in ROC analyses found among the screen/film, CR film, monochromatic CRT, and color CRT, even in the group with very subtle interstitial abnormalities.
In March 1998, the Ministry of Health and Welfare announced that the fee for CRT diagnosis could be covered by the medical insurance in case of the above mentioned electric storage of medical image files.
Telemedicine
Definition of "Telemedicine in Japan" is somewhat different from the previous definitions. It includes (a) image communications, such as teleradiology, telepathology, and video images, (b) not only the communication among medical professionals, but also with patients, (c) not only medical services, but also welfare services, and (d) not only real time jobs, but also batch jobs.
In cases of slow network speeds, the irreversible compression of images is mandatory. It is a big problem to decide up to which compression ratios are acceptable in daily practice. A working group in a committee of the Japan Radiological Society with the research funds from the Ministry of Health and Welfare showed that 2000x2000 10bits digitized image data had sufficient image quality and the irreversible compression of images were acceptable up to 1/10th in general circumstances. They proposed a minimal requirement for digitize film images.
Medical Information System Development Center (MEDIS-DC) proposed a frozen draft, "MEDIS-DC standards for integrated secure communication layer protocols (Ver. 1.00) on August 15, 1998(3)
What is the strong or the weak?
Trials for the PACS started early in Japan, but now it seems to become slow down for a while. The strong was Japanese economy, and the weak could be Japanese economy in future. The early trials for PACS implementation in Japan could be backed up by the strong economy in the past. The strong is the government regulation, and the weak could be slow speed in its de-regulation. The strong is the pressure for the safety or security, and the weak is the pressure for convenience and speed. Even though slow, the steady tides for PACS are on the way with the help of the Internet technology. The strong may be our actual power unaware of, and the weak may be our mind of depression.
References
1.- http://www.mhw.go.jp/english/index.html (English)
2.- http://www.medis.or.jp/std_info.html (Japanese)
3.- http://www.medis.or.jp/e_iscl.html (English)
Corresponding Author:
Hiromu Nishitani, M.D.
Department of Radiology,
Tokushima University Hospital
Kuramoto, 770-8503,
Tokushima, Japan
Fax: +81-886-33-7174
e-mail: hiro(at)clin.med.tokushima-u.ac.jp
Oral presentation at EuroPACS'98, Barcelona, Spain