White Blood Cell Imaging

Identify the energy range(s) and physical half-life for the radiopharmaceutical(s).

In-111 Oxyquinoline - 1/2 life = 2.8 days (67 hrs) - Energy = 173 keV and 247 keV

Explain the general procedure for white blood cell labeling (sedimentation, centrifugation and separation of the red blood cells, centrifugation and separation of the plasma, washing, tagging of radiopharmaceutical and separation for the tagged and untagged white blood cells).

Look at Leukocyte Labeling Diagram

Calculate the labeling efficiency for a patient's labeled white blood cells.

(Activity WBC)/ (Activity WBC + "Hot" LPP) x 100

Identify the substance most likely to interfere with the Tc-99m Ceretec radiolabling procedure and specify its effect on the labeling process

- "Fresh" Tc-99m <2 hours - Important to remove all RBCs because enzymes in RBCs can break down Ceretec

Identify what you should do first after drawing the blood to help expedite the white blood cell labeling process.

- Label the blood with the patient's name, DOB, and date - Place the syringe upside down to allow the RBC's to start settling

Identify the substance most likely to interfere with the In-111 oxyquinoline radiolabling procedure and specify its effect on the labeling process.

- Plasma - Cell Clumping: increased focal areas in the lungs - Hemolyzed blood may produce cardiac activity

Identify the primary indications for performing white blood cell imaging.

1. Detect abscess/infection in soft tissue, particularly in patients with localized findings 2. Diagnose skeletal infection 3. Evaluate inflammatory bowel disease

Explain the appropriate image acquisitions for each of the radiopharmaceuticals.

1. In-111 - Imaging begins at 18-24 hrs post-injection to permit dose localization and bkg clearance -- Early 1-3 hr imaging can be done for inflammatory bowel disease before renal clearance impacts image quality -- Delays possible up to 48 hrs - WB Scan if AOI is unknown (5-10 cm/min scan speed) - Static images taken for 5 mins each or 500Kcts 2. Tc-99m - Imaging begins at 30 mins - 24 hrs post-injection - Imaging for inflammatory bowel disease should begin at 1 hr before renal and biliary clearance can impact image quality - WB scan speed of 10 cm/minute - Static images for 5 mins each

Explain the appropriate routine camera, collimator and computer set up for each of the radiopharmaceuticals.

1. In-111 - LFOV (Dual-head) - Medium energy collimator - Photopeaks at 173 & 247 keV; 20% window 2. Tc-99m - LFOV (Dual-Head) - High Res Collimator - Photopeak at 140 keV with 20% window

Identify the route of dose excretion for each of the radiopharmaceuticals.

1. In-111 Oxyquinoline - Renal 2. Tc-99m Exametazime - Renal & GI

Explain the normal biodistribution (areas of uptake) for the radiopharmaceutical, including the organ receiving the highest RADs for each of the infection radiopharmaceuticals.

1. In-111 Oxyquinoline - Spleen, Liver, Bone Marrow, Lungs. GI, Kidneys, and Bladder 2. Tc-99m Exametazime - Spleen, Liver, Bone Marrow, Lungs, Bowel, GB, Kidneys, and Bladder - Critical Organ = Spleen

Identify the standard adult dose ranges for the radiopharmaceutical(s).

1. In-111 Oxyquinoline -- 500 uCi 2. Tc-99m Exametazime -- 10-20 mCi

Identify the chemical and brand name radiopharmaceutical(s) used in these procedures.

1. In-111 Oxyquinoline (Oxine) 2. Tc-99m Exametazime (Ceretec)

Identify the minimum and ideal amount of blood a technologist should withdraw for white blood cell labeling.

45-60 mL of blood

Explain radiopharmaceutical incorporation in the body for each agent.

Dose incorporates at infection sites via chemotaxis

Explain the role of hetastarch in white blood cell labeling.

Helps speed up sedimentation

Identify the route of administration for the radiopharmaceutical(s).

IV

Determine pertinent patient history, prior procedures and laboratory values for each of the radiopharmaceuticals.

Ideally, patients should have a peripheral leukocyte count of greater than 4000 cells/mm^3; if too low, donor white cells can be labeled

Explain the tagging principle for In-111 and Tc-99m for white blood cell labeling.

Labels all leukocytes: granulocytes, lymphocytes, monocytes, etc.

Identify the patient preparation for each of the radiopharmaceuticals.

No special patient preparation

State the average shelf life for each white blood cell labeling method and for the reconstituted Tc-99m Ceretec dose.

Not to exceed 5 hours after blood draw

Explain how kits and labeled cells should be stored.

Room Temperature

Given a patient or situation, identify which radiopharmaceutical and imaging times would be most appropriate

Tc-99m Ceretec is best used for pediatric patients

Describe and assess the abnormal biodistribution of the radiopharmaceutical in nuclear medicine images and correlate with pathology or medication interference.

Typically focal areas of increased dose uptake though inflammatory bowel disease will give a more diffuse appearance of increased abdominal uptake

Explain the routine imaging views and appropriate positioning for each of the radiopharmaceuticals.

Whole Body and/or statics