Fluke Biomedical 76-419-4150 - Manual (Page 12)

Nuclear Associates 76-419-4150
Operators Manual
2-6
x-ray exposure shall necessitate resetting of the CT conditions of operation prior to the initiation of
another scan.
G. Tomographic Plane Indication and Alignment
1) For any single tomogram system, means shall be provided to permit visual determination of the tomographic
plane or a reference plane offset from the tomographic plane.
2) For any multiple tomogram system, means shall be provided to permit visual determination of the location of
a reference plane. The relationship of the reference plane to the planes of the tomograms shall be provided to
the user in addition to other information provided according to §1020.30(h). This reference plane can be offset
from the location of the tomographic planes.
3) The distance between the indicated location of the tomographic plane or reference plane and its actual
location may not exceed 5 millimeters.
4) For any offset alignment system, the manufacturer shall provide specific instructions with respect to the use of
this system for patient positioning, in addition to other information provided according to §1020.30(h).
5) If a mechanism using a light source is used to satisfy the requirements of paragraphs (g) (1) and (2) of this
section, the light source shall allow visual determination of the location of the tomographic plane or reference
plane under ambient light conditions of up to 500 lux.
H. Beam-On and Shutter Status Indicators
1) Means shall be provided on the control and on or near the housing of the scanning mechanism to provide
visual indication when and only when x rays are produced and, if applicable, whether the shutter is open or
closed. If the x-ray production period is less than one-half second, the indication of x-ray production shall be
actuated for one-half second. Indicators at or near the housing of the scanning mechanism shall be discernible
from any point external to the patient opening where insertion of any part of the human body into the
primary beam is possible.
2) For systems that allow high voltage to be applied to the x-ray tube continuously and that control the emission
of x rays with a shutter, the radiation emitted may not exceed 100 milliroentgens (2.58 x 10 -5
coulomb/kilogram) in 1 hour at any point 5 centimeters outside the external surface of the housing of the
scanning mechanism when the shutter is closed. Compliance shall be determined by measurements averaged
over an area of 100 square centimeters with no linear dimensions greater than 20 centimeters.
I. Scan Increment Accuracy
The deviation of indicated scan increment from actual scan increment may not exceed 1 millimeter. Compliance shall
be measured as follows: The determination of the deviation of indicated versus actual scan increment shall be based
on measurements taken with a mass 100 kilograms or less, on the patient support device. The patient support device
shall be incremented from a typical starting position to the maximum incrementation distance or 30 centimeters,
whichever is less, and then returned to the starting position. Measurement of actual versus indicated scan increment
may be taken anywhere along this travel.