716 Ultrasound in Medicine and Biology September 1986, Volume 12. Number 9

POLICY STATEMENT OF THE JAPANESE SOCIETY FOR ULTRASOUND IN MEDICINE

K. MAEDA

Tottori University, Yonago, Japan

Studies into the safety of diagnostic ultrasound have been conducted in Japan under the support of the Ministry of Health and Welfare in 1972- 1976 for con- tinuous wave ultrasound and 1977-l 979 for pulsed ultrasound. Members of the study group are

S. Sakamoto Tokyo University

M. Hogaki Teikyo University

T. Shimizu Asahikawa Medical University

M. Suzuki Tohoku University

K. Sekiba Okayama University

K. Maeda Tottori University

H. Takeuchi Juntendo University

T. Morohashi Keio University

H. Takemura Osaka University

M. Ide Musashi Institute of Technology

The Committee for the Standards on Ultrasonic Medical Equipment, Japan Society of Ultrasonics in Medicine, stated their considered results as “Views on Safety of Diagnostic Ultrasound,” December 1983. They had come to the conclusion: “regarding the min- imum intensity of ultrasound showing reproducible biological effects obtained from examining reliable lit- erature, when the irradiation time ranged from 10 s to 1.5 h in the frequency range of a few MHz, that it was approximately 1 W/cm2 when continuous wave ultrasound was irradiated, and approximately 240

mW/cm’ (SPTA) in pulsed ultrasound. We have to allow for a sufficient factor of safety when developing actual equipment for ultrasonic diagnosis. Also, we hope that you will excercise sufficient care when per- forming ultrasonic diagnosis. . . .”

The Japan Industrial Standards Committee has imposed limits on the output of diagnostic ultrasound devices used within Japan as follows:

Ultrasonic Doppler Fetal Detector (T1506) less than 10 mW/cm2 (SATA)

Manual Scan B-mode Device (T 1504) less than 10 mW/cm2 (SATA)

A-mode Device (T1503) less than 100 mW/cm’ (SATA)

M-mode Device (T1505) less than 40 mW/cm’ (SATA) The Committee on Medical Engineering of the

Japan Society of Obstetrics and Gynaecology in 1985 presented a Guideline for the Use of Electronic Scan Ultrasonography.

There is no limit on the use of ultrasound elec- tronic scanning devices when the diagnosis is carried out for specific medical indications such as the suspi- cion of abnormality in the pregnant woman, fetus or neonate. The indications include the screening which is done to secure the health ofthe fetus and the pregnant woman.

The use of ultrasound diagnosis for non-medical purpose, i.e. to satisfy a request by the family to know fetal sex or to get fetal image, is not permitted. The ultrasound imaging of pregnant women or the fetus for commercial exhibition is also not permitted.

POLICY STATEMENT OF THE ROYAL COLLEGE OF OBSTETRICIANS AND GYNAECOLOGISTS (RCOG)

OF THE UNITED KINGDOM

A Working Party of the Scientific Advisory Committee issues ofthe current practice of ultrasound in pregnancy of the RCOG was set up to advise it on the advantages and in particular on the possibility that poorly per- and disadvantages of routine ultrasound examination formed ultrasound examination may lead to inappro- in pregnancy. It was also asked to advise on the wider priate clinical action.

First symposium on safety and standardisation of ultrasound in obstetrics 0 G. KOSSOFF and S. B. BARNETT 111

Two basic types of ultrasound equipment are use- ful in obstetric practice. Pulsed ultrasound apparatus is used to image the fetus and uterine contents (usually called ultrasound scanning) while Doppler ultrasound machines are used to obtain continuous tracings of the fetal heart rate. This report is confined to an investi- gation of antenatal ultrasound scanning as it is only this test that is used routinely to screen large numbers of pregnant women. Furthermore, to assess the value of antenatal Doppler recordings of the fetal heart rate would mean comparing the efficacy of this investigation with other predictive tests of fetal wellbeing, such as biochemical assessment of the feto-placental unit which is beyond the brief of this Committee.

RECOMMENDATIONS

1. The present evidence for the safety of ultra- sound based on over 20 years of experience and re- search is sufficiently convincing for us not to recom- mend a change in the common practice of routine ul- trasound examination between 16- 18 wk of pregnancy. However, pregnant women should not be persuaded to have an ultrasound examination against their wishes. While we do not consider that written informed consent to routine ultrasound examination is necessary, such an examination must be accompanied by a written ex- planation as to why the procedure is recommended. Scanning personnel should ensure that mothers have read and understood the content of the written expla- nation.

2. We believe there are cogent reasons to expect benefit to all mothers and babies from a well performed scan between 16- 18 wk of pregnancy, but there is a need for a large well-planned prospective study to de- termine the extent of the benefits of routine scanning over selective scanning on medical indication.

3. Standards in the accuracy of antenatal scanning differ widely from hospital to hospital. In each district hospital with a maternity department, a consultant ob- stetrician or radiologist should personnally undertake a regular weekly scanning session if proper supervision support are to be given to nonmedical personnel.

4. There should be a Diploma of Obstetric Ultra- sound which all personnel performing unsupervised antenatal scanning should hold. The organisation of the examination and the award of the Diploma should

be the responsibility of the Royal College of Obstetri- cians and Gynaecologists, and the Royal College of Radiologists.

5. Ultrasound equipment should be positioned for the convenience of the pregnant mother, within the maternity unit.

6. The antenatal scanning department should be a welcoming place. Scanning personnel should ensure that they establish good contact with every mother ex- plaining the genera1 features of the baby seen on the screen. The husband or a close relative should be al- lowed to observe the antenatal scan. When any ab- normality is found, the explanation must be left to the obstetrician who is responsible for the care of that mother.

7. Commercial exploitation of antenatal scanning by poorly trained personnel merely to let the parents “see the baby” is to be deplored. While there may be emotional and other more practical health benefits to mothers from seeing their fetus on the screen, the bonding process should always be part of a skilled di- agnostic examination.

8. Regional Health Authorities should give greater priority to requests from obstetrical and gynaecological divisions for real-time ultrasound equipment, especially from those divisions with a consultant who has a special interest in obstetric ultrasound.

9. There should be continuing vigilance in terms of monitoring the safety of antenatal ultrasound ex- aminations. At the present time, properly designed case control studies appear to be the most practical means of establishing this aim.

10. At present there are no beam intensity stan- dards for ultrasound equipment sold in the United Kingdom. Manufacturers of diagnostic ultrasound equipment should be required to publish the maximum SPTA and SPTP intensity values for their equipment once a standard method for measuring this has been agreed by the DHSS. A government agency, such as the National Physical Laboratory, should be required to carry out random checks on the power output of the various types of diagnostic equipment and the in- formation from such checks should be freely available. Beam intensity standards should be established for all ultrasound scanning equipment to ensure that the minimum power is used to achieve a satisfactory image.