Safety Biological Safety
38 Lumify Ultrasound System
Philips Healthcare 4535 618 58571_A/795 * MAY 2016
ALARA principle with informed judgment. Additionally, the transducer frequency, system setup
values, scanning techniques, and operator experience allow the sonographer to meet the
definition of the ALARA principle.
The decision as to the amount of acoustic output is, in the final analysis, up to the system
operator. This decision must be based on the following factors: type of patient, type of exam,
patient history, ease or difficulty of obtaining diagnostically useful information, and the
potential localized heating of the patient due to transducer surface temperatures. Prudent use
of the system occurs when patient exposure is limited to the lowest index reading for the
shortest amount of time necessary to achieve acceptable diagnostic results.
Although a high index reading does not mean that a bioeffect is actually occurring, a high index
reading should be taken seriously. Every effort should be made to reduce the possible effects of
a high index reading. Limiting exposure time is an effective way to accomplish this goal.
There are several system controls that the operator can use to adjust the image quality and
limit the acoustic intensity. These controls are related to the techniques that an operator might
use to implement ALARA. These controls can be divided into three categories: direct, indirect,
and receiver controls.
Acoustic Output Limits
This ultrasound system maintains acoustic output below the appropriate limits for each
application, as listed here. The significant difference in magnitude emphasizes the need to
select the correct application and remain in that application, so the correct application limits
are in use for the appropriate application.
Limits for Non-Ophthalmic Applications
• I
spta.3
≤ 720 mW/cm
2
• MI ≤ 1.9
• TI ≤ 6.0
Direct Controls
Application selection and the output-power control directly affect acoustic intensity. There are
different ranges of allowable intensity or output based on your selection. Selecting the correct
range of acoustic intensity for the application is one of the first things that occurs in any exam.
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