Samsung PT60A User Manual download pdf (Page 40)

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Operation Manual

 Applying ALARA

The system-imaging mode used depends upon the information needed. 2D-mode and M-mode

imaging provide anatomical information, while Doppler, Power, and Color imaging provide

information about blood ow. Scanned modes like 2D-mode, Power, or Color, disperse or scatter

the ultrasonic energy over an area, while unscanned modes like M-mode or Doppler concentrate

ultrasonic energy. Understanding the nature of the imaging mode being used allows the

sonographer to apply the ALARA principle with informed judgment. The probe frequency, system

set-up values, scanning techniques, and operator experience aid the sonographer in meeting

the denition of the ALARA principle. The decision as to the amount of acoustic output is, in the

nal 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 diculty of obtaining diagnostically useful

information, and the potential localized heating of the patient due to probe 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 necessarily mean that a bioeect is occurring, it should

still be taken seriously. Every eort should be made to reduce the possible eects of a high index

reading. Limiting exposure time is an eective 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.

 Direct Controls

Application selection and the output intensity control directly aect acoustic intensity. There are

dierent ranges of allowable intensity or output based on your selection. Selecting the correct

range of acoustic intensity for the application is one of the priorities required during any exam. For

example, peripheral vascular intensity levels are not recommended for fetal exams. Some systems

automatically select the proper range for a particular procedure, while others require manual

selection. Ultimately, the user bears the responsibility for proper clinical use. Samsung Medison’s

systems provide both automatic and user-denable settings.

Output has a direct impact on acoustic intensity. Once the application has been established, the

output control can be used to increase or decrease the intensity output. The output control allows

you to select intensity levels lower than the dened maximum. Prudent use ensures good image

quality while employing the lowest output intensity.

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Samsung PT60A User Manual Page 40