This document describes quality control testing of conventional x-ray equipment. It discusses measuring parameters like tube voltage (kVp), milliamperes (mA), and output factor using instruments like an ionization chamber and electrometer. Graphs show the linear relationship between output and the square of kVp. The aim is to detect changes that could degrade image quality or increase patient radiation exposure. Maintaining quality control through regular testing is important for obtaining accurate diagnoses while minimizing dose.

1. Master in Medical Physics 2015 to 2016
Quality control in Conventional X-Ray
Francisco J.Hernández Flores∗
International Centre for Theoretical Physics
franciscohernandez_f2010@hotmail.com
August 7, 2015
Abstract
This task it is about the quality control in Conventional X-Ray, The aim of
the present Quality Control (QC) testing is to detect changes that may result
in a clinically significant degradation in image quality or a significant increase
in radiation exposure. of conventional x-ray such as reproducibility of tube
voltage, dose out put, time, and x-ray tube efficiency, Accuracy of kVp, mA, time.
Examinations of these factors are studied using adequate instrumentation for
measure different parameter in the hospital Majore of Trieste Italy.
I. Introduction
The principle goal of quality con-
trol of x-ray machine is obtain accu-
rate and timely diagnosis. The sec-
ondary goals are minimization of radi-
ation exposure and obtain high image
quality. This can be assess by perfor-
mance the x-ray machine by optimum
operating parameters such as repro-
ducibility of tube voltage, dose out
put, time , x-ray tube efficiency, Accu-
racy of kVp, mA, time, focal spot size
and half value layer.
During this practical we make only
measure about kVp mA and output
factor, we know about the instrumen-
tation used in quality control in radio
diagnostic and which parameter affect
the quality of the imaging.
II. Theory
I. KV Effect
The relationship between x-ray pro-
duction efficiency and KV has a spe-
cific effect on the practical use of x-
ray equipment. As we will see in a
later chapter, x-ray tubes have a def-
inite limit on the amount of electri-
cal energy they can dissipate because
of the heat produced. This, in prin-
ciple, places a limit on the amount
of x-radiation that can be produced
∗Physics of diagnostic X ray 2
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2. Master in Medical Physics 2015 to 2016
by an x-ray tube. By increasing KV,
however, the quantity of radiation pro-
duced per unit of heat is significantly
increased. [2]
II. EFFICACY (OUTPUT)
The x-ray efficacy of the x-ray tube is
defined as the amount of exposure, in
milli Grays, delivered to a point in the
center of the useful x-ray beam at a
distance of 1 m (see fig. 1) from the fo-
cal spot for 1 mAs of electrons passing
through the tube. [2]
The efficacy value expresses the
ability of a tube to convert electronic
energy into x-ray exposure. Knowl-
edge of the efficacy value for a given
tube permits the determination of
both patient and image receptor ex-
posures by methods discussed in later
chapters. Like x-ray energy output,
the efficacy of a tube depends on a
number of factors including KV, volt-
age waveform, anode material, filtra-
tion, tube age, and anode surface dam-
age. The illustration below gives typi-
cal efficacy values for tungsten anode
tubes with normal filtration. [2]
Figure 1: Detector in air at 100 cm from focus [Estimation of output (Ka/mAs) as function of
kV] [1]
III. Material and Methods
For quality control they were used
the following measuring instruments.
meter, ionization chamber parallel
plane, kVp, Electrometer.
The chamber of ionization was po-
sitioned at 100 cm of distance at fo-
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3. Master in Medical Physics 2015 to 2016
cal spot, connected at the electrome-
ter for evaluated the Ka. then mea-
surements began varying the kV with
the same mAs at same distance fo-
cal spot surface this result is shows
in the graph 2. The Quality Control
(QC) in radiography is a central part
of QA programme, which deals with
equipment maintenance and monitor-
ing. QA in diagnostic radiology is
a mean of maintaining standards in
imaging and working towards min-
imizing patient and staff doses. To
accomplish these objectives, a number
of physical parameters that affect the
performance of X-ray imaging system
are to be measured.
IV. Results and discussion
The kV is very useful in controlling the radiation output of an x-ray tube.
The figure below shows a linear relationship, tube output dependence on kV2,
the values obtained i the graph they were measure in the practice, with their
respective error bar
4,000 6,000 8,000 10,000
1.00
2.00
3.00
4.00
kVp2
OutputµGy/mAs
y= 0.0004332 ∗ x − 0.3699
Figure 2: Output (Ka/mAs) as function of kV
V. Conclusion
• In our few experience as stu-
dent, was useful know QC pro-
gram has positive effect on X-ray
equipment performance.
• The graph obtained from the
data measured during practice
meets theory linearity of the out-
put factor when compared to
square kV.
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4. Master in Medical Physics 2015 to 2016
References
[1] Paola Bregant , Lecture Physics of Diagnostic with x-ray 2, ICTP Trieste Italy,
2015.
[2] Perry Sprawls, Ph.D. , The Physical Principles of Medical Imaging, 2nd edition,
May 1995.
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