Technetium Tc-99m Sulfur Colloid is a radiopharmaceutical agent containing technetium that is linked to sulfur. It is used in the scintigraphic scanning of the reticuloendothelial system.

Technetium Tc-99m Sulfur Colloid Uses:

• Imaging agent:

  • It is used in localization and mapping of lymph nodes draining a primary tumor in patients with breast cancer or malignant melanoma when used with a handheld gamma counter.
  • It is also used for reticuloendothelial cell function imaging agents like liver, spleen, and bone marrow.
  • To check the patency of peritoneo-venous (LeVeen) shunt..
  • Esophageal transit studies, gastroesophageal reflux scintigraphy, and detection of pulmonary aspiration of gastric contents.

Technetium Tc-99m Sulfur Colloid Dose in Adults

Technetium Tc-99m Sulfur Colloid Dose in Breast cancer lymph node localization:

• SubQ: 0.1 to 1 mCi (3.7 to 37 MBq) in volumes ranging from 0.1 to 1 mL

Technetium Tc-99m Sulfur Colloid Dose in localization of lymph node in malignant melanoma:

• SubQ: 0.1 to 1 mCi (3.7 to 37 MBq) in volumes ranging from 0.1 to 1 mL

Technetium Tc-99m Sulfur Colloid Dose in Peritoneo-venous (LeVeen) shunt patency evaluation:

• Intraperitoneal injection:

  • 1 to 3 mCi (37 to 111 MBq)

• Percutaneous transtubal (efferent limb) injection:

  • 3 to 1 mCi (12 to 37 MBq) in a maximum volume of 0.5 mL

Technetium Tc-99m Sulfur Colloid Dose in Reticuloendothelial cell imaging:

• Bone marrow:

  • IV: 3 to 12 mCi (111 to 444 MBq)

• Liver/spleen:

  • IV: 1 to 8 mCi (37 to 296 MBq)

Technetium Tc-99m Sulfur Colloid Dose in Esophageal transit studies (gastroesophageal reflux scintigraphy and pulmonary aspiration imaging):

• Gastroesophageal studies:

  • Oral: It is given as 0.15 to 0.3 mCi (5.55 to 11.1 MBq)

• Pulmonary aspiration studies:

  • Oral: it is given as 0.3 to 0.5 mCi (11.1 to 18.5 MBq)

Technetium Tc-99m Sulfur Colloid Dose in Childrens

Technetium Tc-99m Sulfur Colloid Dose in Reticuloendothelial cell imaging:

• Bone marrow:

  • Pediatrics:

    • IV: intravenously it is given as 0.03 to 0.15 mCi/kg (1.11 to 5.55 MBq/kg)

• Liver and spleen:

  • Newborn Infants:
    • • IV: it is given as 0.2 to 0.5 mCi (7.4 to 18.5 MBq)
  • Children and Adolescents:
    • • IV: it is administered as 0.015 to 0.075 mCi/kg (0.56 to 2.78 MBq/kg)

Technetium Tc-99m Sulfur Colloid Dose in Esophageal transit studies (gastroesophageal reflux scintigraphy and pulmonary aspiration imaging):

• Gastroesophageal studies or pulmonary aspiration studies:

  • Pediatrics:

    • Oral or nasogastric tube: 0.1 to 0.3 mCi (3.7 to 11.1 MBq)

Pregnancy Risk Factor C

• Studies on animal reproduction have not been done. Unbound technetium may cross the placenta.
• In fetal tissue, Technetium Tc99m can be detected. The specific formulation, route of administration and stage of pregnancy will determine the amount (Adelstein 1999).
• The potential for radiopharmaceuticals to harm the fetus is dependent on the dosage and stage of pregnancy.
• Radiopharmaceuticals used in therapeutic procedures can cause more damage to the foetus than high doses.
• Modifying a medically necessary diagnostic procedure to reduce fetal risk is possible.
• It is best to delay elective diagnostic procedures until after delivery.
• Women with childbearing potential should not be considered pregnant.
• Manufacturer recommends that pregnant women with reproductive potential be evaluated 48 hours prior to administration.
• The imaging procedure should also be completed within 10 days of the onset of menstruation.

Technetium Tc-99m sulfur colloid use during breastfeeding:

• Breast milk contains technetium Tc99m. However, no conclusive studies on technetium 99m sulfur colloid have been conducted.
• According to literature, breast milk should be pumped and discarded for at least six hours after administration.
• It is advised to avoid contact with infants after receiving a higher dose (>370 MBq).
• Women with a stable milk supply should continue to breastfeed after the administration of radiopharmaceuticals.
• Data on the excretion of technetium 99m into colostrum is not available. Its levels are highly variable and data is sparse.
•  Therefore, early breastfeeding recommendations cannot be made with any certainty.
• Until breastfeeding stops, elective diagnostic procedures should not be performed.
• It may be necessary to comply with all regulatory requirements regarding recordkeeping and instructions to patients, depending on the dose.

Dose in Kidney Disease:

No dose adjustments are provided in literature for renal diseases.

Dose in Liver disease:

There are no dose adjustments required in hepatic impairment.

Side effects of Technetium Tc-99m Sulfur Colloid:

• Cardiovascular:

  • Cardiorespiratory Arrest
  • Flushing
  • Hypotension
  • Localized Blanching

• Central Nervous System:

  • Chills
  • Dizziness
  • Numbness
  • Seizure

• Dermatologic:

  • Diaphoresis
  • Pruritus
  • Scarring (Injection Site)
  • Skin Rash
  • Skin Sclerosis (Injection Site)
  • Urticaria

• Gastrointestinal:

  • Abdominal Pain
  • Nausea
  • Vomiting

• Hypersensitivity:

  • Anaphylactic Shock
  • Anaphylaxis
  • Hypersensitivity Reaction

• Local:

  • Burning Sensation At Injection Site
  • Erythema At Injection Site
  • Swelling At Injection Site
  • Tissue Necrosis At Injection Site (Eschar)

• Respiratory:

  • Bronchospasm
  • Dyspnea

• Miscellaneous:

  • Fever

Contraindications to Technetium Tc-99m Sulfur Colloid:

There have been no studies on specific contraindications.

Warnings and precautions

• Hypersensitivity

  • Rarely, anaphylactic reactions such as hypotension, bronchospasm or urticaria have been reported.
  • It is important to have readily available medication, equipment, or personnel for hypersensitivity reactions management during administration.

• Malignancy

  • Children are at greater risk of malignancy, especially if they are young.
  • It is best to use the lowest possible dose. Safe handling should be a requirement in order to protect patients and healthcare workers.

• Amplification of pulmonary blood:

  • Technetium Tc99m sulfur colloid can be physically unstable. It can settle over time.
  • Larger particles can be trapped in the pulmonary capillary beds after intravenous administration. This could lead to uneven radioactivity distribution.
  • To avoid any particle aggregation or non-uniform distribution, centrifuge the vial before administering.

Monitoring parameters:

• Pregnancy test should be done 48 prior to administration if imaging procedure is not performed within 10 days following the onset of menses.
• Monitor for signs & symptoms of hypersensitivity reactions.

How to administer Technetium Tc-99m Sulfur Colloid?

• The route of administration varies as per indication.
• Agitate the vial or syringe immediately before administration to avoid particle aggregation and to assure uniform radioactivity distribution.

Breast cancer or malignant melanoma, lymph node localization:

• Administer SubQ. It is used concomitantly with a handheld gamma counter to identify nodes.

Peritoneo-venous (LaVeen) shunt patency evaluation:

• Administer either by intraperitoneal injection or by percutaneous transtubal (efferent limb: maximum volume of 0.5 mL) injection.
• Consider patient repositioning or other measures to help assure uniform radiopharmaceutical mixing with the peritoneal fluid.

Reticuloendothelial cell imaging:

• Administer intravenously.

Gastroesophageal imaging studies and pulmonary aspiration studies:

• Administer orally. To facilitate GI reflux imaging, consider administering by nasogastric tube.

Radiopharmaceutical; use appropriate precautions for handling and disposal. Use waterproof gloves and effective radiation shielding when handling.

Mechanism of action of Technetium Tc-99m Sulfur Colloid:

It is a radioactive diagnostic material that decays by isomeric transformation to emit a photon which can be detected using imaging.

Distribution:

• Intraperitoneal: Distributed to the peritoneal fluid
• IV: Distributed to the reticuloendothelial system
• Oral: Distributed through the gastrointestinal tract
• SubQ: Distributed to lymphatic capillaries and then to the lymph nodes

Half-life elimination:

• Half-life, nominal: IV: ~2.5 minutes;
• Half-life, physical: 6 hours

Excretion:

• Oral: Primarily feces

Technetium Tc-99m sulfur colloid International brand names:

Available in specialized centers.

Technetium Tc-99m sulfur colloid Brand Names in Pakistan:

It may be available in certain specialized centers in Pakistan.