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Thallium Study
What is it
''Thallium study' is a general term used for 'Stress myocardial perfusion
scintigraphic study', a test which is aimed at viewing the distribution
of blood to the heart muscle. The distribution varies between a patient
with previous heart attack, a patient of angina and a normal individual.
Thallium 201 (Tl201) and Technicium 99m (Tc99m)- radiopharmaceuticals
are used for this study. These radiopharmaceuticals map the distribution
of blood supply to the heart muscle when imaging is done using a Gamma
Camera/SPECT.This is performed on exercise and at rest.
Before starting to exercise, the patient receives an injection of thallium
201, a radioactive chemical, which is taken up by normal heart muscle
cells.
· Immediately after exercise, heart scans are
performed.
· If muscle tissue is damaged by ischemia (oxygen deprivation),
it will fail to take up thallium and will be detected on the scanned image.
· If the scan detects damage, it is repeated two or three hours
after exercise.
· Damage due to a prior heart attack will persist when the heart
scan is repeated.
· Injury caused by angina, however, will have resolved by that
time.
Why is it done?
To accurately delineate the distribution of blood to the heart muscle
during rest and exercise.
This is helpful in assessing the stress-induced reduction in blood supply
on exercise, to the affected region of the heart muscle.
This determines the severity and extent of ischaemia (reduced blood supply).
When it is done/advised ?
i. Diagnosis of Ischaemic heart disease/ Coronary artery disease.
ii. Assessment of presence, severity and extent of ischaemia due to coronary
artery disease detected by angiography. This helps in deciding the line
of treatment.
iii. For follow and assessment of patients after CABG or PTCA.
iv. Detection of hibernating ('revivable') myocardium (immobile yet living
heart muscle) in patients who already had infarction ('Heart attack').
How is it done?
The patient is asked to do exercise on a treadmill under clinical monitoring.
Gamma ray emitting medical radioisotope, which maps the heart muscle,
is injected by a simple intravenous injection into a superficial vein
of the arm.
A study is acquired under the Gamma Camera/ SPECT after exercise and at
rest (1st & 2nd phase).
Analysis of the study is performed on a computer and a report is generated.
A third phase of the study may be done on the next day if required (for
this the patient has to come at the given time, for about 2 hrs, without
any particular preparation)
Report is given to the patients after 2 working days.
Before ... Precautions & prerequisites
Preparations for the service:
Take an appointment for the study as mentioned above.
Follow the instructions given, which generally are as follows:
Come fasting on the day of the test at 9:00 am or as advised (Water can
be taken).
(Liquids / light solid food is allowed after the 1st phase of the study
is done)
Stop/ allow cardiac medicines on the day of the test as advised (Please
keep the medicines with you).
Bring your old medical records.
An adult/ responsible attendant should accompany the patient.
The appointment is strictly subject to the availability
of the radioactive medicine (Tl201/Tc99m). Please confirm the availability
of the medical radioisotope according to the instructions given.
* Department/ hospital is not responsible for last-moment non-availability
of medicinal radioisotope due to reasons beyond our control.
Tariff
Stress Thallium:
Rs. 8000/-
+ (optional) Rs 80/- for Thallium alert card
Rest Thallium:
Rs. 5000/-
+ (optional) Rs 80/- for Thallium alert card
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