RADIONUCLIDE DETECTION OF INFECTION

GALLIUM SCAN

INDICATIONS:

  1. Detection, localization, and follow-up of infection (sepsis with or without localized signs/symptoms, and FUOs).
  2. Detection and localization of tumors (staging and follow-up of the following:

Lymphoreticular neoplasms (esp. Hodgkin's, histiocytic lymphoma).

Bronchogenic Ca.

Hepatocellular Ca.

Testicular Ca.

Malignant melanoma.

3. Evaluation of interstitial and chronic lung disease as well as sarcoid.

4. Evaluation of patients with acquired immunodeficiency syndrome (AIDS).

5. Evaluation of extent and/or effect of therapy in granulomatous (e.g., sarcoidosis).

PATIENT PREPARATION:

  1. No special preparation required.
  2. Patients should not have received chemotherapy for 48 hours prior to scheduled

injection. Scanning immediately prior to chemotherapy or radiotherapy is

preferred.

RADIOPHARMACEUTICAL:

6-10 mCi Ga-67 citrate is given I.V. depending on the clinical indication. Critical organ is the colon (0.6-0.9 rad/mCi).

SCANNING TIME:

Scanning can be performed at 24, 48, and 72 hours post injection. Tomographic scans take about 45 minutes to acquire. The patient must lie still during this time.

OTHER CONSIDERATIONS:

  1. Gallium has proven very useful in the evaluations of AIDS patients with opportunistic lung infections. Lung uptake often precedes x-ray evidence of disease. Scanning is useful in staging and as a prognostic indicator; it may obviate the need for bronchoscopy in some patients.
  2. Certain tumors are more gallium avid than others. Consultation with the Nuclear Medicine staff is encouraged to best utilize this study.
  3. Imaging sometimes require patient cooperation. If sedation or analgesia will be required, please arrange this prior to scanning.
  4. Ga-67 is retained in the body for over a week post-injection. This may interfere with other nuclear studies. For example, bone scans should be performed first if both studies are planned.
  5. Gallium is secreted in breast milk and nursing is not possible after injection (until the next pregnancy).

6 The choice between gallium-67 citrate and labeled white blood cells for cases of occult infection is generally made on the basis of chronic vs. acute infection. Tagged white blood cell studies are better for acute infection and suspected abdominal pathology. Gallium-67 citrate should be used for chronic infections. When there are any questions, please feel free to consult the Nuclear Medicine staff.

RATIONALE:

Gallium acts as a ferric ion analog and in plasma is bound to transferrin, lactoferrin and other plasma proteins. Uptake in tumors appears to involve the Ga-tranferrin complex. Uptake at sites of infection and inflammation is not well understood and may involve complex deposition as well as bacterial uptake.