When you get a nodule, you're
concerned, particularly if the doctor reports it as a “hot” or “cold” nodule on
your scan. These terms are frightening-sounding but are commonly used by
doctors to refer to how a thyroid nodule appears on a nuclear medicine thyroid
scan. A thyroid nodule refers to an abnormal area or a lump in the thyroid
gland. Most thyroid nodules do not cause any significant health problems;
however, some need additional testing. A scan of the thyroid is helpful to
assess how much tracer the nodule is consuming, as well as how much it takes up
or does not take up when compared to the rest of the thyroid tissue.
Dr Nikunj Jain takes care of
consultation, evaluation of the thyroid, nuclear medicine radioactive isotope
scanning, and giving suitable therapy in one place in Molecular Diagnostics andTherapy. He explains to his patients what their thyroid scan results mean and
if more tests or treatment may be necessary.
What Is a Thyroid
Nodule?
The thyroid gland is located in the
front of the neck in a butterfly shape. A small area within it can develop
differently from the rest of the thyroid gland, creating a nodule. Thyroid
nodules are common and can develop at any age. Some are found incidentally in a
routine examination, others because of a swelling in the neck, and others as
part of an ultrasound or other imaging procedure. Central thyroid nodules are
not cancerous. Your doctor may, however, recommend further tests based on the
size, appearance, thyroid hormone levels, and other factors of your nodule, as
well as your symptoms and other risks.
What Is a Thyroid
Nuclear Medicine Scan?
A thyroid scan helps to determine how
the thyroid works. A tiny dose of radioactive tracer is given, and the
radioactive tracer is absorbed by the thyroid. Then, a special camera is used
to create images of the distribution of the tracer throughout the gland. While
an ultrasound is mostly used to identify the structure and appearance of the
thyroid gland, a nuclear medicine scan will be able to reveal the activity of
various sections of the thyroid. This type of functional information is helpful
especially if a patient has a thyroid nodule and their thyroid hormone levels
are abnormal.
What Does a “Hot”
Thyroid Nodule Mean?
A hot nodule is known as focal tracer
uptake that exceeds that of the rest of the thyroid. This means that the nodule
is working and making thyroid hormone. Hot nodules develop in many individuals
with an overactive thyroid, and may lead to hyperthyroidism. Patients can have
symptoms like rapid heart rate, sweating, anxiety, shivering, thinning body
fat, or hyperthermia. Importantly, a hot nodule is very unlikely to be a cancer
compared to a non-functioning or cold nodule. The information provided by the
scan is, however, only part of the overall assessment and will be taken into
account together with blood work, ultrasound, symptoms, and other clinical
data.
What Does a “Cold”
Thyroid Nodule Mean?
When a thyroid area absorbs less tracer
than any other area of the thyroid, the area is called a cold nodule. It means
that the part of the thyroid gland is not as active or is not working in the normal
fashion as the rest of the thyroid tissue. Not all cold nodules are cancer.
People who have a non-functioning thyroid nodule are unlikely to have a thyroid
tumor since most of the time these nodules just aren't working. Some patients,
however, who have developed thyroid cancer may have a cold nodule, which might
require additional work-up. Depending on the characteristics of the nodule, an
ultrasound, bloodwork, or a fine-needle aspiration biopsy may be considered by
the doctor.
Does a Hot Nodule Mean
Cancer?
Generally, hot thyroid gland nodules
are less likely to be cancerous. But no scan can be read independently. The
doctor may also take the clinical history, ultrasound appearances, thyroid
hormone levels, and other investigations into consideration. If unusual or
suspicious characteristics are found, additional evaluation may be suggested.
Getting a scan report doesn't necessarily mean panic. The overall clinical
picture should be considered when using the report.
Does a Cold Nodule
Mean Cancer?
No. Don't confuse a cold nodule with a
cancer diagnosis. A large number of cold nodules are harmless. The word “cold”
only refers to the level of uptake of the tracer to the nodule during the
thyroid scan. It will not tell you if the nodule is cancerous. If the
ultrasound and/or other clinical features are concerning, the doctor may want
to perform further tests, such as a biopsy, to investigate the nodule's
characteristics.
Why Are Blood Tests
Also Important?
A thyroid scan gives information on
thyroid function, and a blood test gives information on thyroid hormone levels.
Your doctor might use tests to see if your thyroid is too active, too slow, or
normal. A number of tests can determine these things, including tests for TSH,
T3, and T4. The results help to understand if a nodule is linked to specific
symptoms or Pathology scan results.
What Role Does
Ultrasound Play?
The information from ultrasound exams
is different from information gathered using different nuclear medicine exams.
During a thyroid ultrasound, the technology provides a view of the size, shape,
internal consistency, and density of a thyroid nodule. It also indicates the
features that would need to be further assessed. On a nuclear medicine scan,
however, the scan helps you to determine how efficiently the nodule is used.
Research properly conducted with these investigations could provide physicians
with a fuller picture of a thyroid nodule.
What Happens After a
Thyroid Scan?
Whether or not a treatment is
indicated, and if so, which treatment, are determined by the results of the
scan and the patient's condition. In a patient with hyperthyroidism, a scan
might reveal a normal hot nodule, in which case the doctor explores treatment
options. They include medicine, radioactive iodine treatment, or other
treatments. Additional evaluation is indicated based on other risk factors,
nodule size, ultrasound appearance, and symptoms of the nodule if cold. A
biopsy can also be recommended in certain cases.
Can a Hot Nodule Be
Treated With Radioactive Iodine?
Yes. Radioactive iodine therapy may be
a successful treatment for certain individuals who have overactive thyroid
tissue. Radioactive iodine can be taken up by overactive thyroid cells, which
slowly decrease their activity. Radioactive iodine therapy, however, is not the
standard treatment for all cases of hypothyroidism due to a "hot nodule”.
Before Dr. Nikunj Jain prescribes treatment, he takes the thyroid function test
result, thyroid scan results, symptoms from the patient, medical history, and
other factors into consideration.
What If Your Thyroid
Nodule Is Cold?
When the cold nodule does occur,
another procedure is required. It is not as useful in giving information about
the function of the nodule and is more closely examined by the physician for its
structural characteristics. An ultrasound can help to determine which planned
steps are needed to evaluate the nodule and, in some cases, a fine-needle
aspiration biopsy may be suggested. What's key is that “cold” doesn't equal
“cancer”. It is just that the nodule doesn't take up as much tracer as the rest
of the thyroid gland on the thyroid scan.
Why Should You
Consult a Nuclear Medicine Specialist?
Medical terms are used in thyroid scan
reports that could be difficult for the patient to understand. A specialist has
the opportunity to discuss their findings and their implications in relation to
the patient's blood tests, symptoms, and other investigations. Dr. Nikunj Jain,
nuclear medicine specialist, evaluates results from the thyroid scan to decide
if more tests or treatment is needed. His participation can range from
consultation and diagnostic evaluation through nuclear medicine therapy as
appropriate.
Conclusion
The terms "hot" and
"cold" thyroid nodule refer to the behavior of a thyroid nodule in a nuclear
medicine scan. A cold nodule absorbs less tracer and tends to be more active. A
hot nodule is less likely to be cancerous, and a cold nodule might need to be
checked further. But both terms together are not an adequate diagnosis. Blood
tests, ultrasound, symptoms, and some medical history may be all critical, and
in some cases, it may be important to do a biopsy.
If you have had your thyroid scanned
and don't know what the results of the scans show, Dr. Nikunj Jain, Molecular
Diagnostics and Therapy, can help you understand the report and what you should
do next. Patients receive full thyroid care all under one roof, from
consultation to nuclear medicine scanning to appropriate therapy here at our
centre.