CLINICAL APPLICATION Flashcards
– participate in body function.
Endocrine System
The secretion into the bloodstream of substances is
known as
Hormones
_____ have profound effects on overall body
function and metabolism.
Hormones
Endocrine System consists of:
- Pituitary Gland
- Pancreas
- Adrenal Gland
- Gonads
____ is used in management of
patients with disorders of the thyroid gland,
hyperthyroidism and thyroid carcinoma.
Radionuclide Therapy
____ is located in the neck.
Thyroid Gland
Thyroid Gland is sometimes ____-shaped in the
adult
butterfly
Lobe weighs approximately:
10 grams
The thyroid gland secretes the thyroid hormones:
Thyroxine (T4) and Triiodothyronine (T3)
These hormones regulate tissue metabolism and are
essential for normal body development and
maintenance of function.
T4 and T3
Iodine is reduced to ____ and is actively trapped by the thyroid gland.
neutral iodine or iodide
there are increase T4 and T3 syntheses and secretions as well as increase in TBG.
Hyperthyroidism
TBG -
Thyroxine-Binding Globulin
there is a decrease in thyroid hormone and in the absolute amount of TBG, and in the T4 or T3 levels are low.
Hypothyroidism
____ is the most widely used procedure for the measurement of circulating serum T4 and T3 and provides the most
direct estimate of thyroid function.
Radioimmunoassay
____ are also available to measure thyroglobulin,
the intrathyroidal binding protein.
Assays
____ are based on the unique avidity of the thyroid gland for iodine and the availability.
In Vivo Functions Tests and Imaging
In Vivo utilizes ____, an isotope that decays by beta decay and that is readily available as a product of nuclear fission and neutron bombardment in nuclear reactors.
Iodine-131
the most common in vivo
procedure.
Thyroid Uptake Test
____ is absorbed more rapidly than capsules
Liquid
The uptake is usually complete at ____ hrs.
18-20
____ is used to determine the size, location, and function of the thyroid gland and to evaluate palpable findings near or within the thyroid gland.
Thyroid Gland Imaging
Choice of Radionuclides in Thyroid Imaging:
- I-131
- Tc 99m
Dosage for thyroid imaging:
5-15 mCi
Introduction of medicine for thyroid imaging:
Intravenous
Waiting time or delay for thyroid imaging:
10-20 mins
Patient Positioning for thyroid imaging:
Supine, Hyperextended neck
Static Views of Chest for thyroid imaging:
ANT, RAO, and LAO
Isotope used for radionuclide therapy:
I-131
Preparation for radionuclide therapy:
low iodine diet 1 week before therapy
Dosages for radionuclide therapy:
5-30 mCi for hyperthyroidism
50-200 for thyroid carcinoma
Introduction of medicine for radionuclide therapy:
Oral
Patient admission for radionuclide therapy:
1-3 days
images are acquired for radionuclide therapy in ____ hrs
48-72
Static views of chest for radionuclide therapy:
ANT neck and chest
___________ reported their initial observations on the distribution of I-128 T1/2 of 28 min in rabbits, they noted: radioactive iodine may be of clinical or therapeutic significance.
Herts, Roberts, and Evans
At which year was the I-128 observed:
1938
I-131 was synthesized by _____ shortly thereafter.
Seaborg
reported the complete disappearance of
multiple functioning metastasis in a patient with
thyroid carcinoma.
1946
Treatment doses for thyroid carcinoma:
30-75 mCi to ablate remnants
75-150 to treat local (cervical) metastases
150-300 to treat distal metastases
Radionuclide imaging of the skeleton is being used
with increasing frequency in the evaluation of abnormalities involving _____
bones and joints
introduced the development of Tc99m labeled phosphate complexes for bone imaging
Subramanian in 1971
Tc99m in the form of ____ does not
localize to any useful extent in bone.
Pertechnetate
The ____ half-life of Tc99m allows several millicuries of activity to be injected.
shorter
____ are similar to pyrophosphonate and EHDP
but have faster blood clearance.
MDP and HMDP
MDP -
Methylene Diphosphonate
HMDP -
Hydroxymethylene Diphosphonate
____ is believed to offer greater stability than pyrophosphate.
EDHP
EDHP -
Ethylenehydroxyphosphonate
Indications for Bone Scan:
- Staging of malignant disease
- Evaluation of primary bone neoplasms
- Diagnosis of early skeletal inflammatory disease
- Determine bone visibility
- Evaluation of total joint prosthesis
The most frequent reason for ordering a bone scan is ____ by determining if spread to bone has occurred.
Staging of malignant disease
What are seen in the anterior images of bone scan?
anterior skull, ant iliac spine and pubic rami
What are seen in the posterior images of a bone scan?
posterior skull, spine, posterior ribs, scapulae, sacroiliac joints, and ischia
Shoulders hips and extremities are commonly seen well on ____ views.
both
Metastases to the spine are difficult to detect radiographically, since loss of approximately ____of the mineral content
of the bone must occur
50%
isotope used for a bone scan?
Tc 99m
pharmaceutical used for bone scan?
MDP or HMDP
dosage for bone scan:
15-30 mCi
Introduction of medicine for bone scan:
Intravenous
____ is generally an adequate time for good bone accumulation and a low soft tissue level of the radiopharmaceutical.
3 hours
How long does the bone scan take?
2-4 hours
Unless contraindicated, patients should be ____ to aid in clearance of the radiopharmaceutical from the body.
hydrated
Administration of _____ of liquid during the
delay period and should be voided frequently to decreases the radiation dose.
4-6 glasses
____ before the procedure starts to avoid obscurity of the pelvis due to accumulation of medicine in the bladder.
Void
patient positioning for bone scan:
supine
static views of chest for bone scan:
ANT, RAO, RLAT, RPO, POS, LPO, LLAT, LAO
Indications for radionuclide renal scintigraphy.
- Relative renal function
- Renal Transplant Evaluation
- Acute Renal Failure
- Obstructive Uropathy
- Renovascular Hypertension
- Infection and Inflammation
____ is the most common radionuclide renal imaging study performed
MAG3 and DTPA
MAG3 -
Mercaptoacetyltriglycine
DTPA -
Diethylenetriaminepentaacetic acid
Functional renal imaging can be used to determine
both _____
absolute and renal function
Relative renal function is calculated using an early (1
– 2 or 2 – 3 mins min projection) image of the
____
kidneys
Several caveats in determination of relative renal
function:
- Calculation of renal function
- Attenuation
This method was shown to be effective by Haynie
and his colleagues, who injected labeled _____
ceramic microspheres
The development of MAA is by _____ in 1964
Taplin & Coll and Wagner & Coll
MAA -
Macroaggregated Albumin
After intravenous injection the particles, which
measure ____ in diameter, pass through the
right atrium and right ventricle, where they are well
mixed with blood, and then into the pulmonary
artery.
30-40 um
A satisfactory perfusion image can be obtained with
anywhere between _____ particles in a
normal patient.
60,000 and 150,000
If too few particles are given, the scans have an
obvious ____ appearance
blotchy
method of injection for MAA:
intravenous
Standard Perfusion Imaging includes the six basic
views:
Posterior, Anterior, Right & Left Laterals, and
Right & Left Posterior Obliques.
Posterior view first for ____ counts, and then
each of the other views for the same time that it
takes to do
500,000
3 aspects of ventilation are often examined.
- Distribution of Single Breath
- Distribution of Lung Volume
- Distribution of the efficiency of ventilation from
the clearance of radioactive xenon
Thyroid Cancer RAI Treatment
- Post-surgery
- Ablations of remnants and metastases
- Reduces recurrences, metastases, mortality
Determines the overall function of the thyroid
gland
Thyroid Scintigraphy
RAI-
Radioactive Iodine
ATD
Antithyroid Drugs
Adjuvant therapy for well differentiated thyroid
cancer
Radioactive Iodine
TSH
Thyroid-stimulating hormone
