Bones - unit 1

Area of interest in the foot to get the best delay images you would have the patients come back in......

- 24 hours (4 phase)

The radiopharmaceutical used for bone imaging

- Tc99m MDP

All of the following are reasons for a bone scan expect

- Headache

The crystalline structure of bone is known as

Hypoxyatpite

In the case of a patient with a question of infection in t1 what does the literature say you use to visualize the infection

GA67 Citrate

Which of the following indications requires 3-phase bone imaging? MENTIONS SPECIFIC BODY PART

- Suspected loosening of a hip prosthetic or hip pain, RSD of the right hand, osteomyelitis of the left foot

In a normal patient, what is the percentage of the injected dose of TC-MDP is taken up by the bones?

- 50%

Approximately how much blood is drawn from the patient for a while blood cell scan for injection?

- 50-60 mL

When labeling leukocytes with In-111 oxine, what is the next step in the procedure after blood has been drawn in a syringe containing an anticoagulant?

1. Centrifuge the sample at 200 g. for 5 minutes

2. Remove red blood cells

3. Allow 50 to 60 minutes for the blood sample to sediment

4. Add the In-111 oxine

5. Add ascorbic acid

Allow 50 to 60 minutes for the blood sample to sediment

Cardiac uptake on a bone scan is indicative of what?

- Recent heart attack (weeks or days)

In class, we looked at bone scans questioning osteomyelitis of the toe. To magnify the toes in question and get a better look, Which collimator would be used?

- Pinhole collimator

All the following are categories of bone types except

- Rhomboid

The humerus is located

- Proximal arm

The middle part of the spine is called

- Thoracic

The ulna is located in

- Lower arm (distal)

The mandible bone is located in

- The skull

What is the critical organ in an IN111 WBC scan

- The spleen

White cells are labeled with GA67 Citrate for a white cell scan. (HMPAO IN111 are for WBC)

- False

How is a bone scan dose administered to a patient

- Injection into a vein

Which of the following radiopharmaceutical characteristics is not desirable for bone imaging?

- Slow Blood Clearance

Avascular necrosis would appear on an image as

- Cold spot

Free tech or TC04 in the 99M TC-MDP preparation can lead to visualization of what on 3-hour delayed images?

- Thyroid and stomach

Which of the following characteristics is least likely associated with metastatic malignancy on the bone scan?

- Distal extremity involvement

The half-life of TC99M is

- 6 hours

The below scan may demonstrate all of the following except (super scan)

- Normal Pediatric epiphyseal uptake

Your patient comes back for delays and you see this, What is going on

- Arterial injection (glove syndrome)

The below image is a SPECT/CT whole-body scan. The patient is a 65 year old male who has a history of prostate cancer, What is going on?

- Metastatic disease

What is the percentage of lytic change in bone needed to be visible on a bone scan?

- 10%

Visualization of the kidneys on a TC 99m-MDP scan is considered

- Normal because TC99m-MDP is excreted via the urinary tract

Patients having a bone scan should be encouraged to void frequently between injection and delayed scanning to

- Reduce radiation due to the bladder

What normal areas of uptake of missing on a superscan

-kidneys

The below image is an example of

fractures in a pediatric patient

SPECT stands for

- Single photon emission computed tomography

You have 5-year-old child come in for a bone scan. What dose should be given?

- reduced pediatric dose based on weight

The below scan demonstrates

- infiltrated dose in the arm

All of these are indications for NM imaging of the skeletal system except

diagnosis of tendon abnormalities

The accumulation rate of radionuclides in the bone is related to both the rate of bone production and

- Vascularity (blood flow)

What soft tissue is normal to see on a bone scan

breast

When obtaining a posterior view of the lumbar spine how far away should be collimator be placed from the patient?

as close as possible

What are the energy photopeaks for a IN111 WBC scan?

173 to 247 keV (medium collimator)

What is the optimal time delay for a F18 bone scan post-injection?

30-60 minutes

Osteoblasts are associated with

bone building

What is the order of a 3-phase bone scan

flow images, blood pool, delayed images

How long after injection of a tracer does the blood pool phase start

5 minutes

Osteomyelitis is

infection of a bone

The method of uptake and localization for Tc-99m MDP in the bone is

Heterionic exchange

A patient with prostate cancer comes in for a bone scan, they receive an intramuscular injection of 25 mCi Tc99m MDP. They come back in 3 hours for the delayed images, what was done wrong

wrong method of dose administration

The patient comes in for an IN111 WBC scan for a suspected abdominal infection. 10CC of blood are taken, labeled with 0.5 mCi of the dose, and injected back into the patient. The patient comes back for images at 4 and 24 hours afterward, what was done wrong?

the wrong amount of blood was taken

For a bone scan for an adult patient with metastatic breast cancer, what portion of the anatomy should we cover?

the whole body

What are the two types of bone tissue?

compact and spongy

What collimator is used for an IN111 WBC scan?

Medium energy

What is the best radiopharmaceutical to use if you are looking for activated bone marrow?

Tc99m Sulphur Colloid

How much fluid should a patient ideally have prior to a bone scan?

4-6 cups

GA67 citrate is the preferred tracer when imaging

suspected infection of T6 spine

The femur is located in

the upper leg

Before starting a bone scan, a patient should be instructed to remove all the following metal except

a pacemaker or defibrillator

What is the only contraindication for a bone scan

pregnancy

What is the opposite of anterior?

Posterior

The ordering physician believes that an adult patient should receive both a bone scan and a Ga67 scan to fully rule out a certain type of infection. What order should these scans be completed in?

the bone scan before the Ga67 scan

All of the following types of cancers metastasize to bone except

brain

A patient does not empty their bladder before a bone scan what effect does this have on a scan?

bladder uptake is increased

Based on the prior question scenario where the patient doesn't empty their bladder before a scan, what additional actions should be taken?

additional spot views of the pelvis should be taken after the patient empties their bladder

What is the adult dose of Tc-99m MDP

20-25mCi (740-925MBq)

What is the critical organ for Tc-99m MDP tracer? What is the dose?

bladder, excretion is primary renal
about 0.1-0.2rad/mCi

What is the whole body dose for Tc-99m MDP?

about 0.1 rad/mCi

What is the half life of Tc-99m?

6 hrs

name the two pharmaceutical tracers for Tc-99m

MDP and HDMP

What is the accumulation mechanism for Tc-99m? list some theories of this.

localization related to the exchange of ions with bone known as Heterionic exchange - exchange of native bone ion for another labeled bone-seeking ion

F-18 exchanges with OH group
analog elements of calcium exchange with calcium
phosphate compounds exchange with phosphorous groups onto calcium of hydroxyapatite

What are some factors that may influence osseous lesion uptake of Tc-99m

increased blood flow to osseous lesions

areas and rate of new bone formation

newly forming hydroxyapatite crystals are smaller than mature ones and provide great surface areas for binding

What is the patient prep and any precautions for bone scans? How can we decrease soft tissue in bone scans? What radiopharmaceutical do we use for bone scans?

explain procedure - patient should understand reason for delay between injection and imaging (to allow tracer to bind to bones

patient should be hydrated frequently and voiding frequently to improve soft tissue clearance and avoid excess radiation to bladder

tc-99m MDP or tc-99 HMDP

What is a three phase bone scan (tc-99m)? why would there be a fourth phase?

blood flow - multiple images taken quickly during or immediately after injection (eg. over 60sec, 1 image/sec)

blood pool - slower photo rate, multiple images taken over a period of time (ex. 5 min)

planar imaging - delayed images after 3-4 hours, usually not Whole body

fourth phase - image taken at 24hr to aid tissue clearence

What cancers typically metastasize to bone?

Lung, breast, prostate, kidney and thyroid cancer

What collimator is used for Tc-99 scan? Which one should not be used?

140 keV or high or medium resolution

high sensitivity should not be used

What types of delayed bone scans can be performed?

spot imaging

whole body

SPECT

Pinwhole - type of collimator

• used in certain types of pediatric bone scans and some thyroid

• filter is focused on a certain area

When would a 3 phase bone scan be used?

when trying to differentiate between osteomyelitis or diskitis

Why is SPECT of interest for bone imaging?

improved contrast of lesions

able to see areas that bones block on planar scans, allows for etter localization of abnormal accumulation

provides 3d info about disease

sometimes shows lesions not visible on planar view

What types of patients usually get SPECT scans?

suspected disease of hips, lumbar spine, knees, temporalmandibular joints and facial bones

What type of collimator does SPECT scans use?

low energy, high resolution, parallel hole

What radiopharmaceutical is usually used?

Tc-99m MDP or Tc-99m HMDP

What radiopharmaceutical is used for pet scans? What is it’s activity range in adults? What is the activity range in kids?

F-18

adults - 5-10mCi

kids - 0.5-5 mCi, max dose not exceeding adult

What are the half lives of F-18?

1st phase - 0.4 hr

2nd phase - 2.6 hr

What are the indications would require a bone scan?

staging malignant disease

eval of primary bone neoplasms

diagnosis of early skeletal inflammatory disease

eval of skeletal pain of unknown cause

eval of elevated alkaline phosphatase of unknown cause

determination of bone viability

eval of painful joint prostheses

Where do we inject for a bone scan?

in a vein, in an area without suspected activitye

You see a cold spot on a bone scan, what could this be a sign of? What type of abnormality of bone could also cause this?

avascular necrosis(lack of circulation leading to tissue death)

broken bones or dislocated joints leading to AVN

How much of a lytic change in bones before it’s detected on a bone scan vs xray?

bone scan 5-10%, xray 50-80%

What is the composition of bone? Including osteoblasts and osteoclasts

60% inorganic

30% organic - 90% collagen, ground substance and cells

5-10% water

What is osteomyelitis? What causes it? what are some symptoms?

local or generalized infection of bone marrow

trauma, or surgical introduction of bacteria

bone pain, tenderness, muscle spasms, fever of unknown origin (FOU)

What types of radiopharmacuticals can be used to diagnose osteomyelitis in nuclear medicine imaging?

In 111-WCS, TC 99m - WCs, Tc 99m-HMPAO, Ga 67- citrate

What is the physical half life of indum-111 white cells?

67 hr or 2.8 days

What are the gamma emissions of Indium-111?

173 and 247 keV

How does In-111 oxine bind to white blood cells?

diffuses across WBC membranes

How are WBCs prepared for In-111 oxine tagging?

separated via gravity sedimentation and centrifugation

Is contamination with other cell types high for In-111?

no

In-111 oxine can be used to label WBCs suspended in plasma. True or False

False - cannot be labeled if suspended in plasma

what is the critical organ in an In-111 WC test? what is the general activity dose? are there any side effects?

spleen

about 9-14 rads/0.5mCi

no adverse effects

What is the technique for In-111 WC labeling? How much In-111 oxine used to tag adult WBCs?

about 60cc of patient’s blood removed, gravity sedimentation to remove majority of RBC, centrifugation to separate the rest

for adults - 500 uCi of In-111 used to tag WBC

When are images typically performed for In-111 WBC procedures? when would early images be performed? when would you do delayed images?

typically 18-24 hr after injection

early images at 1-4 hours

sometimes later images at 48 hr

What’s the most important thing in an In-111 imaging test?

that patient receives their own blood

the technician who draws blood often has to re-inject