The operational guidelines for conducting fetal imagining ultrasounds consist of two basic rules: (1) for medical reasons and (2) time and intensity as low as reasonably achievable (ALARA). Proper use of the equipment is explained in the literature from the manufacturer. Both manufacturers and educational institutions provide training.


Guidance for Industry and FDA Staff – Information for Manufacturers Seeking Marketing Clearance of Diagnostic Ultrasound Systems and Transducers. National Council for Radiation Protection and Measurements. (created by US Congress)

Exposure Criteria for Diagnostic Ultrasound, II: Criteria Based on All Known Mechanisms. Bethesda, MD: National Council for Radiation Protection and Measurements; 2002. Report 140.


Furthermore, because laboratory studies have shown the potential for both thermal and mechanical bioeffects at diagnostic acoustic output levels, and because of the particular concern for fetal exposures (Stratmeyer 2003), prudent use has been advocated by national and international bodies concerned with medical ultrasound use and safety (AIUM 1994, Barnett et al. 2000, BMUS/BIR 2000, Health Canada 2001, Nyborg, 2002, NCRP 2002). Two mechanisms have been advanced to help clinical users employ this concept: providing the maximum levels of acoustic output in the device labeling (AIUM 2008) and incorporating an acoustic output display on the device (AIUM 1994, IEC 2007, AIUM/NEMA 2004a). This guidance recognizes both of these mechanisms. For devices that follow the Track 1 recommendations (Section 2), acoustic output information should be included in the Operator’s Manual. A tabular format such as shown in Examples 2-2 and 2-3 may be useful for this purpose. For devices that follow the Track 3 recommendations (Section 3), the system should incorporate the output display according to AIUM/NEMA 2004a or IEC 2007, and the labeling should include acoustic output information. A tabular format such as shown in Example 3-4 may be useful for this purpose. Although the completed examples need not accompany the 510(k) submission, Section 1.6.1 suggests the basic elements of the acoustic output test methodology that should be described in the submission. Provide clearly stated indications for use, contraindications, warnings, precautions, and a prescription device statement where appropriate. This includes (but is not limited to):

  1. a precaution to perform the ultrasound procedure prudently using the principle of ALARA (As Low As Reasonably Achievable);
  2. for Track 1 systems, a caution when applicable (see also Table 2-1 and Section 2.2.4) that the device is not intended for fetal use (either in the operator’s manual, individual transducer manuals, or on equipment labeling);
  3. a description of the warnings, displays, or other system responses of the device to fault conditions; ……
3.4 Track 3 – Education Program for the Clinical End User.

3.4.1 ALARA Education Program
You should provide an ALARA education program for the clinical end-user that covers the subjects listed below. ALARA is an acronym for the principle of prudent use of diagnostic ultrasound by obtaining the diagnostic information at an output that is As Low As Reasonably Achievable. This education program should include explanations of:

  1. the basic interaction between ultrasound and matter,
  2. the possible biological effects,
  3. the derivation and meaning of the indices,
  4. a recommendation to use and the need to follow the ALARA principle in all studies, and
  5. clinical examples of specific applications of the ALARA principle.

You may wish to provide a document published by the AIUM, “Medical Ultrasound Safety” (AIUM 1994), to meet the generic content of the educational program. You should also provide information specific to your device regarding ALARA.