Type of test Nuclear scan

Normal findings

 Normal size, shape, position, and function of the thyroid gland No areas of decreased or increased uptake

 Test explanation and related physiology

Thyroid scanning allows the size, shape, position, and physiologic function of the thyroid gland to be determined with the use of radionuclear scanning.

Thyroid nodules are easily detected by this technique. Nodules are classified as functioning (warm/hot) or nonfunctioning (cold), depending on the amount of radionuclide taken up by the nodule. A functioning nodule could represent a benign adenoma or a localized toxic goiter. A nonfunctioning nodule may represent a cyst, carcinoma, nonfunctioning adenoma or goiter, lymphoma, or localized area of thyroiditis.

Scanning is useful in patients with

• A neck or substernal mass

 • A thyroid nodule. Thyroid cancers are usually nonfunctioning (cold) nodules.

 • Hyperthyroidism. Scanning assists in differentiating Graves disease (diffusely enlarged hyperfunctioning thy roid gland) from Plummer disease (nodular hyperfunctioning gland).

• Metastatic tumors without a known primary site. A normal scan excludes the thyroid gland as a possible primary site.

• A well-differentiated form of thyroid cancer. Areas of metastasis may show up on whole-body nuclear scans.

Thyroid scanning is usually preceded by a thyroid uptake scan. An iodine-123 capsule is given to the patient 6 to 24 hours before measuring iodine uptake. After uptake counts are obtained, Tc 99m⁰⁴ is administered intravenously. Scan images are then obtained as described earlier.

Another form of thyroid scan is called the whole-body thyroid scan. This scan is performed on patients who have previously had a thyroid cancer treated. An iodine-131 capsule or solution, Tc 99m⁰⁴, or iodine-123 is given orally, and the entire body is scanned to look for metastatic thyroid tissue. A hot spot indicates recur rent tumor. This test is routinely performed (every 1-2 years) on patients who have had a thyroid cancer larger than 1 cm.

Contraindications

 • Patients who are allergic to iodine

• Patients who are pregnant unless benefits outweigh risks Potential complications

• Radiation-induced oncogenesis. This complication is minimized if technetium or low-radioactive iodine isomers are used instead of iodine-131.

 Interfering factors

• Iodine-containing foods

• Recent administration of x-ray contrast agents Drugs that may affect test results include cough medicines, multiple vitamins, oral contraceptives, and thyroid drugs.

Procedure and patient care

 Before

* Explain the procedure to the patient. See p. xviii for radiation exposure and risks.

• Check the patient for allergies to iodine.

* Instruct the patient about medications that need to be restricted for weeks before the test (e.g., thyroid drugs, medications containing iodine).

 • Obtain a history concerning previous contrast x-ray studies, nuclear scanning, or intake of any thyroid-suppressive or anti thyroid drugs.

* Tell the patient that fasting is usually not required.

 During

 • Note the following procedural steps:

 1. A standard dose of iodine-123 is usually given to the patient by mouth 6 to 24 hours before scanning. The capsule or solution is tasteless.

2. Iodine uptake is measured. IV technetium is administered, and thyroid imaging is performed 2 hours later.

3. At the designated time, the patient is placed in a supine position, and anterolateral images of the thyroid area are obtained. The whole-body imaging protocol is somewhat different.

4. The radioactive counts are recorded and displayed.

 • Note that this study is performed by a radiologic technologist in less than 30 minutes and is then interpreted by a nuclear medicine physician.

* Tell the patient that no discomfort is associated with this study.

After

* Usually the dose of radioactivity used in this test is minimal and considered harmless. No isolation and no special urine precautions are needed. However, if higher doses of radionuclide are used, isolation for 24 hours may be recommended.

 Abnormal findings

- Adenoma

- Toxic and nontoxic goiter

- Cyst

- Carcinoma

- Lymphoma

- Thyroiditis

- Graves disease

- Plummer disease

- Metastasis

- Hyperthyroidism

- Hypothyroidism

- Hashimoto thyroiditis

اخر الاخبار

اخبار العتبة العباسية المقدسة

العتبة العباسية المقدسة: نهج البلاغة مصدر صافٍ للفكر والمعرفة ومحصِّنٌ من الشبهات

العتبة العباسية المقدسة تطلق محاضرات محفل نهج البلاغة الأسبوعي في ذي قار

العتبتان المقدستان الحسينية والعباسية تدعوان للمشاركة في مهرجان الشموع بنسخته السادسة والعشرين

بالتعاون مع مستشفى الكفيل.. قسم الشؤون الطبّية يواصل إقامة البرنامج التدريبي لملاكاته النسوية

المزيد

الآخبار الصحية

الصحة العالمية تكشف حقيقة انتشار فيروس نيباه خارج الهند

متى يصبح محيط الخصر "مؤشر خطر"؟

دراسة تكشف دور "العوامل الوراثية" في تحديد عمر الإنسان

رائحة كريهة في الجسم.. "علامة خفية" أخطر مما تتصور

المزيد

الآخبار التكنلوجية

مايكروسوفت تكشف عن الجيل الثاني من شرائحها للذكاء الاصطناعي

خرافة "ثمانية أكواب يوميا".. كم من الماء يحتاج جسمك فعليا؟

هل توجد حياة خارج كوكبنا؟.. اكتشاف جديد يثير اهتمام العلماء

اكتشاف الخلايا المسؤولة عن فقدان ذاكرة الطفولة

المزيد

مواضيع ذات صلة

thyroid fine needle aspiration biopsy (FNAB, Skinny needle thyroid biopsy, Fine-needle aspiration [FNA])

thoracentesis and pleural fluid analysis (Pleural tap)

The Role of Laboratory in Urgency: Altered State of Consciousness

Preoperative Laboratory Test

sputum culture and sensitivity (C&S, Culture and Gram stain)

sodium (Na), blood

small intestinal bacterial overgrowth test (SIBO test, Lactulose Breath Test)

Clinical Biochemistry of Exercise: The Benefits of Movement

Medium- to Long-term Effects of Physical Activity on Laboratory Parameters

Acute Effects of Sports Performance on Laboratory Parameters

ProstaScint scan (Radioimmunoscintigraphy of the prostate [RIS])

pregnanediol