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Breast Scintigraphy
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Breast MIBI Scintigraphy
Breast cancer is considered as the most common
malignancy in women population in several counteries
such as USA, Austeralia and European couteries. On
average, women life-time risk of breast cancer is 1 in
12. Mortality from breast cancer is relatively stable
although that the incidence is increased. This due to
one or all of the following reasons:
·
The improvent in breast cancer therapy.
·
The improvenment in breast diagnosis through breast
screening programes.
·
Identification of non-fatal cancers.
Breast screening programes are designed to test for
initial signs of breast cancer in large numbers of
asymptomatic women population. In the United Kingkom,
the screening programme is implemented to screen women
aged 50-64 years at 3 years interval by the use of
mammography to perform a single medial-lateral oblique
view. Mammography is considered the first step in the
diagnosis procedures. However, mammography technique has
its limitations with respect to sensitivity and
specificity. Follow-up tests are required to confirm the
exact nature of lesions seen on mammography examination.
A number of imaging techniques provide further
diagnostic information, these are as follows;
1.
"Spot" mammography.
2.
Ultrasound.
3.
Magnetic resonance imaging (MRI).
4.
Computed Tomography (CT).
5.
Nuclear Medicine techniques.
Nuclear medicine techniques depend on the physiological
distribution of a radiolabelled tracer. This tracer (a
radionuclide) is normally attached to a carrier molecule
(a metablite). After labelling, the reconstitute is
known as radiopharmaceutical. In most cases, the
radiopharmaceutical dose is injected into a peripheral
vein and circulates around the body.
Cancer cells are hungry for metabolites such as glucose
and, therefore, take up the metablite along with any
associated radiotracer. Because cancer cells are more
metabollically active than the cell surrounding them, a
concentration of the radiotracer builds up in the cancer
cell. This appears as an area of increased focal uptake
when imaged with a gamma camera.
Scintimammography is a nuclear medicine technique which
can deliver breast imaging as sensitive as X-ray
mammography and MRI in palpable tumours but with greater
specificity. Sensitivity of 86-95% have been reported in
sestamibi studies for palpable breast tumours and 60-91%
in non-palpable tumours. Specificity values have been
reported as 62-93%. The data obtained can significantly
increase the understanding of the nature of any breast
lesions. It also provides a complementary images for the
diagnosis and treatment of breast cancer.
Imaging Procedures:
Radionuclide:
·
Technetium-99m.
Reagent:
·
Methoxy-isobutyl-isonitrile (MIBI) (Manufacturer: IZINTA).
or
·
Sestamibi, Cardiolite (Manufacturer: Du Pont).
Radiopharmacutical Dose:
·
25-30 mCi (925-1110 MBq)
Injection site:
·
Intravenously in the foot area ( To exclude any
possibility of axillary lymph node uptake ).
Positioning and Acquisition:
·
The patient lays prone.
·
Static images using Parallel Hole collimator.
·
128 x 128 matrix size.
·
10 minutes acquisition time.
·
No zoom applied.
·
Anterior views:
1)
2 minutes anterior image with marker on the nipple.
2)
10 minutes anterior image without marker.
·
Right and left lateral views:
1)
2 minutes lateral images with marker on the nipple.
2)
10 minutes lateral images without marker.
1 Scintigraphy, A guide to good practice, John Buscombe,
Jonathan Hill and Santilal Parbhoo
1 Scintigraphy, A guide to good practice, John Buscombe,
Jonathan Hill and Santilal Parbhoo |
