3 Phase Bone Scan

Indications:
  • Osteomyelitis
  • Bone Trauma
  • Arthritis
  • Cellulitis
  • RSD
  • Loosening of a Prothesis

Contraindications:
  • Pregnant or Breastfeeding.
  • Has had a Technetium based scan in last 48 hours.
  • Has had a Barium study in last 72 hours.

Radiopharmaceutical information:
  • Radionuclide: Tc-99m
  • Radiopharmaceutical: MDP or HDP
  • Adult dosing: 20mCi (740 MBq)
  • Pediatric dosing: Adult Dose x [(age+1)/(age+7)] Minimum 2mCi.
  • Method of administration: IV Bolus injection (Right or Left Anti-cubital) ( If you are imaging the hands or arms only inject into the foot)
  • Method of Localization: Chemisorption
  • Physical Half-life: 6 hours

Patient Preparation:
  1. NPO 4-6 hours prior to exam.
  2. Discontinue sedatives or narcotics 12 hours prior to exam.
  3. Patient should be well hydrated, void bladder immediately prior to study.
  4. Remove all metal objects.

Equipment Used:
Type of Camera or Probe - Gamma Camera

Collimator used: LEHR or LEAP

Acquisition Setup:

Dynamic: View(s)
Matrix:128x128 or 64x64
Time/Frame: 1-2 seconds over 60 seconds
Number of Frames: 30-60

Statics: View(s)
Matrix:128x128, 256x256 or 512x512
Total Counts or Duration: 5 minutes or 300-500k
torso: 1000 kcounts
head/knees: 500 kcounts
feet, hands, fibula, tibia: 300 k counts

Whole body: View(s)
Matrix: 256x1024, 512x1024, or hires 8 deep
Scan Speed: 10-12 cm/min
Start/stop points: Start a few cm above the patients head. Stop a few cm past the patients feet.

SPECT:
Not generally done for a 3-phase.


Procedure:
  1. Administer a 20mCi (740 MBq) bolus of Tc-99m MDP is injected Intravenously.
  2. First phase consists of 2-5 second dynamic images acquired for 60 seconds each for the flow and then the blood pool images will be acquired right after. Dynamic images can be either LEHR or LEGP.
  3. After injection, patient is told to drink several cups of fluid and to void regularly.
  4. After 2-4 hours, patient will return for delayed images.
  5. Look for any signs of urinary contamination and use a LEHR collimator to take delayed images of suspected pathologies.


Normal Uptake and common varients:
  1. Normally uptake at growth plates in adolescent patients
  2. Uptake at sacroiliac joints and lordotic curvature of spine.
  3. Normally uptake in kidneys and bladder; sometimes ureters are present.

Abnormal Uptake and causes:

3phase.gif


A 3-phase bone scan was used to evaluate this 74 year old woman with chronic left ankle pain and no history of trauma. There is increased activity

of the radiopharmaceuitcal in the left foot as is seen in the flow, blood pool and delayed imaging. When the images were taken it was noted that there was increased swelling around the left foot leading to a diagnosis of RSD.

Artifacts:
arterial_injection.gif

The patient was being diagnosed for hip pain with no significant findings, a whole body scan was done afterwards with a static of the hands which resulted in increased radiotracer in the right hand. It was concluded that an intra arterial injection occurred resulting in increased uptake of the radiopharmaceutical by the bones nearest and distal to the injection site because of Tc-99m MDP's affinity for bone uptake.
Questions asked in Patient History:
List the common questions asked when taking a patient history for this specific procedure.

Are you Pregnant or Breastfeeding?(Tell patient that they must pump their breast milk for 24 hrs post study)
Any recent injuries, falls, fractures?
Any history of Arthritis?
Do you have any history of cancer? What kinda and for how long?
Have you had any chemotherapy or radiation therapy? (When was their last treatment?)
Any allergies?
Any recent diagnostic tests?(CT, X-ray, MR ect.) What type, when and where?
Any trouble holding still?
Have you ever had any surgery? What type and when?
Any recent dental work? What kind?
Are you taking medications?
If so, what? Check for contraindications.
Do you have any pain? If so where? Also for how long?


References:
  1. The Requisites, Nuclear Medicine,Third Edition; Harvey A Ziessman, Janis P. O'Malley, James H. Thrall, Mosby, Elsevier (2006)