Aims and objectives
The aim of this work was to evaluate the entrance skin dose reduction in the thyroid by using radiation protection in mammography exams.
More specifically,
to evaluate the entrance skin dose (ESD) at the level of the thyroid,
with and without protection,
using thermoluminescent dosimeters (TLD); and verify the differences of ESD at the thyroid between craniocaudal (CC) and mediolateral oblique (MLO) views on mammography.
Methods and materials
Quantitive and experimental study,
it was divided into two phases:
Descriptive study,
where a statistical survey of the technical parameters (kV,
mAs) was performed.
In the second phase,
experimental simulations were carried out in order to verify the dose received on thyroid gland,
using a General Electric (GE) Senograph DMR+ mammographer with two bucky's,
one thyroid lead protection (0.5mm),
a body phantom (used only for positioning) and PMMA plates (which allowed simulating the breast tissue with a thickness of 4,5cm).
In the experimental stage a...
Results
The results of ESD wihout and with protection are presented in Fig. 2 and Fig. 3 .
In the configuration without lead protection,
the ESD received by the thyroid was superior in medio-lateral oblique projection (44 µGy) compared to the cranio-caudal projection (36 µGy).
With the lead protection there is a dose reduction of 83,3 % in the canio-caudal projection (6 µGy ) and 93,2% in the medio-lateral oblique projection (3 µGy).
In the mammography (four projections),
the use of the lead protection reduce of...
Conclusion
Thyroid protection allows effective reduction of scattered radiation in mammography exams.
The dose received by the thyroid is very low,
and consequently the probability of cancer induction is also extremely low.
Given the significant reduction of the dose and the principle ALARA,
we can conclude that the shield should be used by the mammography exam.
However the use of the shield may provide artifacts,
making difficult the correct analysis of the breast tissue and leading to the examination repetition increasing the radiation exposure of the...
Personal information
Daniela Entradas (BSc),
Collaborator in the Medical Imaging and Radiotherapy Department,
Health School - University of Algarve,
Portugal.
Sónia Rodrigues (MSc),
Professor in the Medical Imaging and Radiotherapy Department,
Health School - University of Algarve,
Portugal.
Radiographer in Centro Hospitalar Universitário do Algarve,
Portugal.
E-mail:
[email protected]
Rui Almeida (MSc),
Professor in the Medical Imaging and Radiotherapy Department,
Health School - University of Algarve,
Portugal.
Radiographer in Centro Hospitalar Universitário do Algarve - Faro,
Portugal.
Researcher in CICS.NOVA.UÉvora (Interdisciplinary Centre of Social Sciences – Évora Centre)...
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