Presentation Thyroid scan.pptx

7/27/2019 Presentation Thyroid scan.pptx

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MUHAMMAD SAFWAN BIN AHMAD FADZILA127946

DIAGNOSTIC IMAGING AND RADIOTHERAPY

FACULTY OF HELATH SCIENCE

UNIVERSITI KEBANGSAAN MALAYSIA

THYROID SCAN

(HOSPITAL KUALA LUMPUR)


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Thyroid Gland

The thyroid is a gland that makes and storesessential hormones that help regulate:

the heart rate

blood pressure

body temperature

the rate of chemical reactions (metabolism) in the body.

It is located in the anterior neck just below theAdams apple.

The thyroid gland is the main part of the body thattakes up iodine.


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Anatomy of thyroid glands


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Patient history

Female

Indian

MRN PN2011/2620

DOB

13/10/1970 Age 43 years old

Married

Address

Sungai Buloh


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Clinical history (Sign and symptom)

Increased sensitivity to heat

Frequent sweating

Difficulty sleeping

Tremor

usually a fine trembling in the hands andfingers

Increase appetite

Tachycardia


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Previous medical investigation

Physical exam Difficulty in swallowing. Trembling of the fingers.

Blood test Low levels of TSH in blood which is 0.2 (normal range = 0.3 - 5.0

U/mL) High level of T3 (triiodothyronine) which is 1.2 (normal range = 0.2

- 0.5 ng/dL)

Ultrasound Enlargement of the right lobe of thyroid.

Surgery partial thyroidectomy of left lobe three years ago.


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Impression

Indication: Hyperthyroidism

Enlargement of right lobe, homogeneous thyroidgland with a pyramidal lobe.

The area of the larger nodule is warm. Activity of right thyroid is more than normal (hot

nodules).


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Patient preparation

If the patient had any tests, such as an x-ray or CTscan, surgeries or treatments using iodinatedcontrast material within the last two months, theprocedure should be delayed 6 weeks later.

Stop taking medications or ingesting othersubstances that contain iodine, including kelp,seaweed, cough syrups, multivitamins or heartmedications.

Tell the doctor if the patient has any allergies toiodine, medications and anesthetics.

Nil orally a night before the procedure been done.

Tell the doctor if you are pregnant or breastfeeding.


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Procedure

Prepare the radiopharmaceutical which is 185 MBq (5mCi) of Tc-99m pertechnetate.

Ask the patient to change to hospital gown. Set an IV line on the patient.

Measure the reading of the full syringe under the gammacamera. Ask the patient to lie down (supine) on the couch with

pillow under neck to get extended neck.


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Procedure

Inject the patient with the radiopharmaceutical. Thesyringe is flushed twice to ensure that all themeasured activity is injected.

Setup the collimator.

Delay 20 minutes.

Scan the thyroid (AP/LAO/RAO/SPECT) for 200kcount.

Ask the patient to void and change the cloth. Measure the reading of empty syringe under the

gamma camera.


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Analysis

The study is analyzed by carefully outlining the thyroidand defining a background area using irregular region ofinterest (thigh) .

Uptake (%) = x 100

TR = thyroid region counts per second

Bkgd = background counts per second

SC = counts per second of dose measured in syringe preinjection

DC = decay correction factor


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Images


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Pinhole VS LEHR collimator

HKL PPUKM


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Pinhole VS LEHR (parallel hole) collimator

Cone-shaped collimators Generates magnified

images of a small organ

Limited field-of-view

(200 diameter)

Hexagonal, circular holestypically

Projects an image of thesame size as the object onto

the detector Wide field of view (540x400

mm)


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Discussion

Thyroid imaging is conventionally obtained by planaracquisition using a high-resolution large-field-of-viewparallel-hole collimator, although a pinhole collimatorhas proven to increase the sensitivity of conventional

scintigraphy. According to Ghanem et al. 2011 there were 40 nodules

of different sizes detected by pinhole imaging and only 10(25%) of these nodules were observed on parallel-holeimages.

Pinhole imaging must be used for thyroid imagingparticularly in patients suspected of having nodulardisease.


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Tomas et al. 2008

Pinhole imaging was significantly more sensitive thanparallel-hole imaging (89% vs. 56%; P = 0.0003) for all54 lesions.

Specificity did not significantly differ between pinholeand parallel-hole imaging (93% vs. 96%, P = 0.29).

Pinhole imaging was significantly more sensitive thanparallel-hole imaging for single-gland disease (96% vs.67%, P = 0.001).

Because sensitivity is significantly higher, thyroidimaging of the neck should be performed with a pinholecollimator.


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Fujii et al. 1999

Pinhole collimator showed better efficiency andspatial resolution in the distance where the thyroidscan are actually performed.

In the phantom study and clinical study of 30patients, the nodular activities modeling parathyroidlesions were visualized better on the images obtainedusing the pinhole collimator.

Pinhole collimator was thought to be more suitablefor parathyroid scintigraphy than the parallel-holecollimator.


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Conclusion

Pinhole collimator has proven to be a high-resolutionand sensitive method in both experimental andclinical studies for thyroid scan (Spanu et al. 2004).

Pinhole collimator is recognized as having very highspatial resolution, superior to that achieved withconventional SPECT with a parallel-hole collimator

due to the more favorable geometric properties of thecone beam collimator.


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References

Fujii, H., R. Iwasaki, K. Ogawa, J. Hashimoto, K. Nakamura, E.Kunieda, T. Sanmiya, A. Kubo & K. Inagaki 1999. [Evaluation ofparathyroid imaging methods with 99mTc-MIBI--the comparison ofplanar images obtained using a pinhole collimator and a parallel-hole collimator].Kaku Igaku 36(5): 425-33.

Ghanem, M. A., A. H. Elgazzar, M. M. Elsaid & F. Shehab 2011.

Comparison of pinhole and high-resolution parallel-hole imagingfor nodular thyroid disease. Clin Nucl Med36(9): 770-1.

Spanu, A., A. Falchi, A. Manca, P. Marongiu, A. Cossu, N. Pisu, F.Chessa, S. Nuvoli & G. Madeddu 2004. The usefulness of neckpinhole SPECT as a complementary tool to planar scintigraphy inprimary and secondary hyperparathyroidism.J Nucl Med45(1): 40-

8. Tomas, M. B., P. V. Pugliese, G. G. Tronco, C. Love, C. J. Palestro &

K. J. Nichols 2008. Pinhole versus parallel-hole collimators forparathyroid imaging: an intraindividual comparison. J Nucl MedTechnol36(4): 189-94.


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Presentation Thyroid scan.pptx