2007 International Nuclear Atlantic Conference - INAC 2007
Santos, SP, Brazil, September 30 to October 5, 2007
ASSOCIAÇÃO BRASILEIRA DE ENERGIA NUCLEAR - ABEN
ISBN: 978-85-99141-02-1
INFLUENCE OF THE INPUT VOLTAGE ELECTRIC
CONFIGURATIONS
AND FALL OF INTRINSIC VOLTAGE OF THE EQUIPMENT OF X
RAYS ODONTOLOGICAL PERIAPICAL IN THE KVP
Laranjeira, A. S., Almeida, C. D.1
1
Instituto de Radioproteção e Dosimetria (IRD / CNEN - RJ)
Av. Salvador Allende s/n
22780-160 Rio de Janeiro, RJ
[email protected]
[email protected]
ABSTRACT
The concessionaire of electric energy does not supply a input voltage stable (in the city of Rio De Janeiro the
LIGTH only guarantees the single-phase supply and a band of 116 the 132 VCA). As the devices of rays X
odontological periapical conventional do not possess voltage regulator, kVp of the tube of rays X are influenced.
These devices are found in two basic electric configurations of nominal input voltage, 110 and 127 VAC. As the
input voltage (Vin) as seen it is not fixed, depending on the used configuration, a different nominal kVp will be
generated one (above or below). In this process it also participates the fall of intrinsic voltage in the entrance of
the headstock (after timer). The tests had been made in a device of rays X with electric configuration of 110
VAC, 60 kVp and 10 mA, simulating the conditions of variation of the electric net in laboratory. It was used, a
digital multimeter, a not invasive measurer of kVp and a Variac. The values of used Vin for the tests had been,
110, 118, 127 VAC. The corresponding values for the fall of intrinsic tension and kVp had been respectively, of
99 (- 10% of the Vin), 103 (- 13% of the Vin) and 111 VAC (- 12% of the Vin), and for kVp 60, 63 and 69 kVp.
It was concluded that the Vin varied kVp, making with that it was above or below its nominal value, depending
on the used electric configuration, and that the fall of intrinsic tension of the tested device did not affect kVp.
1. INTRODUCTION
Since its discovery X rays have been used in medical and odontological diagnostic, having
brought however in the past of its use more damages of what benefits. In result of this, it had
the necessity of control in its use, what it is made daily in clinics and odontological offices
through the quality control of the radiographic image.
The devices of X rays odontological periapical conventional do not possess no type of
voltage regulator, being exposed to any variation of the Vin that supply them, bringing in
consequence the variation of kVp in the tube of X rays. These devices basically possess two
input electric configurations, 110 and 127 VAC, that combined with the variation of the Vin
will increase or reduce nominal its kVp.
The tension in the electric net of distribution of the concessionaires is not fixed, but it varies
diverse conditions in accordance with, such as: climate of the region, customs, culture,
economic condition, etc. In the city of Rio De Janeiro for example, concessionaire LIGHT
guarantees the single-phase supply enters the 116 to 132 nominal VAC delivers in the
measurer of electric energy of the consumer. This variation is an inherent phenomenon to the
electric installations in a general way, is commercial, industrial, domestic or the proper
system of distribution of electric energy.
In accordance with to regulation 453/98 kVp is one of the parameters that do not have to
vary, so that it has success in the radiográfico quality control. This work therefore, has the
objective to verify and to quantify the influence that the variation of the entrance tension
(Vin), the input electric configurations and the fall of intrinsic voltage of the odontological X
rays, have in its kVp.
DEVELOPMENT
2.1 Materials and Methods
For the tests a odontological device of X rays Funk X10 of 110 VAC/60 kVp/10 mA nominal
was used. A measuring equipment of kVp was also used not invasive, NonInvasive X Ray
Meter Victoreen 4000M+. To measure the input voltage in the device, a digital multimeter
Minipa MIC 2200A was used. For the simulation of the variation of the input voltage a
VARIAC was used (device that from the tension of the electric net, produces in its exit an
adjustable tension). For the verification of kVp four values of Vin had been chosen, 90, 110,
120 and 130 VAC. Initially Vin in the Variac was adjusted for 90 VAC, and turn on the
device. For the other Vin process was made the same. For the verification of the voltage fall
three values of Vin had been chosen, 110, 118 and 127 VAC. Initially Vin in the Variac was
adjusted, after that the turn on the device became measuring it voltage in the headstock. For
the other Vin the procedure was repeated.
The gotten data had been placed in spread sheets for verification of the variation of kVp, of
the fall of voltage and influence of the input electric configuration in kVp.
2.2 Results and Discussion
The gotten results of kVp, and the percentages between the values of Vin and the values of
kVp are in Table 01. For the percentile values of variation we can observe that it has a linear
relation enters the input voltage and kVp, that is, when the input voltage varies, kVp also
varies proportionally, though with small differences.
V
%V
Kvp
%Kvp
90
-18,18
49,40
-15,56
110
0,00
58,50
0,00
120
9,09
62,00
5,98
Variation of Vent X kVp
Table 01
INAC 2007, Santos, SP, Brazil.
130
18,18
69,00
17,95
For the fall of intrinsic voltage of the tested device we can observe in Table 02 that, even so it
has had a fall of reasonable voltage, this did not intervene with kVp.
Vent Tom
110
118
127
V Cabeçote Queda V%
99,03
102,67
111,20
-0,10
-0,13
-0,12
kVp
59,91
63,30
68,26
Fall of voltage X Fall of percentile voltage X kVp
Table 02
The basic configurations of input voltage in devices of X rays odontological are 110 and 127
nominal VAC. For the configuration of the tested device, we can verify in Table 01, that when
the input voltage is 90 VAC the kVp is 49 kVp, when is 110 VAC the kVp is next to the
nominal one, when is 120 VAC the kVp was for 62 and with 130 VAC the kVp was for 69,
thus changing its initial electric configuration. For devices of 127 VAC and 60 kVp for
example would occur the inverse one approximately. When he was in 127 VAC the kVp
would be 60, and when in 110 VAC the kVp would be around 10 to 13% smaller who kVp
nominal.
3. CONCLUSIONS
With the gotten results concludes, that the variation of the input voltage in the device of X
rays periapical odontological, modifies nominal its kVp, that the input electric configuration
of 110 VAC makes with that the device works above of nominal its kVp and that one of
configuration of 127 VAC works below, considering the band of supply of the concessionaire
(the 116 to 132 VAC), and that the fall of intrinsic voltage of the tested device did not affect
kVp.
REFERENCES
1. Brasil. PORTARIA 453, de 01 de junho de 1998. Aprova o Regulamento Técnico que
estabelece as diretrizes básicas de proteção radiológica em radiodiagnóstico médico e
odontológico, dispõe sobre o uso dos raios-X diagnósticos em todo território nacional e
dá outras providências. Agência Nacional de Vigilância Sanitária, Ministério da Saúde.
Iten 5.7ai.
2. LIGTH CONCESSIONÀRIA DE ENERGIA ELÉTRICA. Tensão nominal em Volts. Rio
de Janeiro –RJ - Brasil. 2007.
3. NEGRISOLI, M. M. Instalações elétricas: projetos prediais em baixa tensão. Itajubá – SP
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4. SPYRIDES, KYRIA SPYRO. Avaliação do controle de qualidade e proteção radiológica
na cidade do Rio de Janeiro. 2002, x, 92f. : il. Tese de Doutorado. Universidade Estadual
de Campinas, Faculdade de Odontologia de Piracicaba. p. 53, 54, 56, 69.
INAC 2007, Santos, SP, Brazil.
5. WUERMANN, A. H.; MANSON – HING, L. R. Radiologia Dentária. Rio de Janeiro Brasil, Guanabara Koogan, 1985. p. 08 e 35.
INAC 2007, Santos, SP, Brazil.