Ceretec (Technetium TC 99m Exametazime) is used in stroke and non-stroke patients for cerebral perfusion scintigraphy. It is also used for leukocyte-labled scintigraphy to localize the site of infection and inflammation.

Indications of Ceretec (Technetium TC 99m Exametazime):

• Imaging agent:

  • Leukocyte labeled scintigraphy:

    • It is given as an adjunct in the localization of intra-abdominal infection and inflammatory bowel disease.

  • Cerebral scintigraphy:

    • It is recommended as an adjunct in the detection of altered regional cerebral perfusion in stroke patients.

  • Off Label Use of Technetium Tc-99m exametazime in Adults:

    • It can be used in cerebral perfusion imaging in patients without a stroke.
    • It can be also used to localize non-abdominal infectious sites.

Ceretec (Technetium TC 99m Exametazime) Dose in Adults

Ceretec (Technetium TC 99m Exametazime) Dose in Cerebral perfusion imaging (stroke):

• IV (based on a 70 kg patient): 15 to 30 mCi (555 to 1110 MBq) is the recommended dose.
• The imaging is performed 30 to 90 minutes after administration and complete imaging within 4 hours after administration. Planar or SPECT imaging techniques may be utilized.

Ceretec (Technetium TC 99m Exametazime) Dose in Cerebral perfusion imaging (non-stroke) (off- label):

• IV: 15 to 30 mCi (555 to 1,110 MBq).
• The images  can be obtained after 40 minutes and by then will be interpretable; however, images obtained after 90 minutes will provide the best quality.

Ceretec (Technetium TC 99m Exametazime) Dose in Leukocyte-labeled scintigraphy in intra-abdominal infection/ inflammatory bowel disease:

• IV: Tc 99m-labeled leukocytes: 5 to 10 mCi (185 to 370 MBq). The dynamic imaging can be performed for the first 60 minutes after administration.
• The static imaging may be performed at 30 to 90 minutes, then at 2 to 4 hours, and if necessary, 18 to 24 hours after administration.

Ceretec (Technetium TC 99m Exametazime) Dose in Leukocyte-labeled scintigraphy in non-abdominal infection/ inflammation (off-label):

• IV: Tc 99m-labeled leukocytes: 5 to 10 mCi (185 to 370 MBq). One should obtain delayed imaging at 4 to 8 hours. If early images are negative, then longer imaging time up to 16 to 24 hours is recommended.

Ceretec (Technetium TC 99m Exametazime) Dose in Childrens

Ceretec (Technetium TC 99m Exametazime) Dose in Cerebral perfusion imaging (stroke):

• Children ≥2 years and Adolescents:

  • IV: 0.4 mCi/kg (14 MBq/kg). The minimum dose of 3 mCi (110 MBq) is indicated. One should not exceed the maximum administered activity for an adult.
  • Perform imaging 30 to 90 minutes after administration and complete imaging within 4 hours after administration. Planar or SPECT imaging techniques may be utilized.

Ceretec (Technetium TC 99m Exametazime) Dose in Leukocyte-labeled scintigraphy in intra-abdominal infection/ inflammatory bowel disease:

• Children ≥2 years and Adolescents:

  • IV: 0.2 mCi/kg (7.4 MBq/kg). The minimum dose of 2 mCi (74 MBq) is recommended. Do not exceed the maximum administered activity for an adult.
  • The dynamic imaging can be performed for the first 60 minutes after administration. However, static imaging can be performed at 30 to 90 minutes, then at 2 to 4 hours, and if necessary, 18 to 24 hours after administration.

Pregnancy Risk Category: C

• The placenta can be crossed by technetium Tc99m exametazime. Technetium Tc99m can be detected in fetal tissue depending on the formulation and route of administration. (Adelstein 1999).
• The likelihood of a radiopharmaceutical causing fetal harm depends on the dose received by the fetus, and the trimester.
• High doses of radiopharmaceuticals that are used in therapeutic procedures can cause fetal harm.
• To reduce fetal risk, a medically necessary diagnostic procedure should not be performed.
• To prevent harm to the fetus, elective diagnostic procedures should not be performed until after delivery.
• Women with childbearing potential should avoid pregnancy.

Technetium Tc-99m exametazime use during breastfeeding:

• Breast milk contains Technetium Tc99m. Exametazime excretion is unknown.
• After the mother has received technetium Tc99m exametazime, the manufacturer suggests that formula feeding be resumed for 60 hours.
• A case report shows that a mother who was nursing was given technetium Tc99m exametazime500 mBq IV. The peak activity was found in breast milk 6.5 hours after the injection. The calculated effective dose (0.26mSv) was low enough to not require interruption of breastfeeding.
• Some studies suggest that breastfeeding should be stopped for up to 12 hours when technetium Tc99m exametazime radiolabels autologous leukocytes.
• Women with a stable milk supply should continue to breastfeed until the radiopharmaceutical product is administered.
• Technetium Tc 99m in colostrum can be found in varying amounts and has only been studied within a limited range of limits. It is therefore impossible to reintroduce early breastfeeding.
• It is important to delay elective diagnostic procedures until after breastfeeding has stopped.
• The dose will determine whether or not the regulations for recordkeeping and instructions to patients are applicable.

Ceretec (Technetium TC 99m Exametazime) Dose adjustment in kidney disease:

• The risk for toxicities might be increased in patients with renal impairment. 
• Tc 99m is significantly secreted by the kidney. There are no specific dosage adjustments provided in the manufacturer’s labeling.
• However, dose reduction can be considered if an adequate number of labeled white blood cells are administered.

Dose adjustment in liver disease:

• According to the literature no dose adjustments are required in patients with hepatic impairment.

Side effects of Ceretec (Technetium TC 99m Exametazime):

• Cardiovascular:

  • Facial edema
  • Transient hypertension

• Dermatologic:

  • Erythema
  • Skin rash

• Miscellaneous:

  • Fever

Contraindications to Ceretec (Technetium TC 99m Exametazime):

Literature does not contain any contraindications.

Warnings and precautions

• Hypersensitivity reactions

  • Hypersensitivity reactions (including anaphylaxis) can occur.
  • Therefore, emergency resuscitation equipment and trolley should always be available.

• Radiation accumulation:

  • The patient's cumulative long-term radiation exposure is increased by the administration of Tc99m.
  • A higher risk of malignancy is associated with long-term cumulative radiation exposure.
  • Pediatric patients are at greater risk due to their longer life expectancy and greater radiosensitivity.
  • To minimize radiation exposure for the patient and staff, ensure safe handling

• Renal impairment

  • It is mostly excreted by your kidneys. Patients with impaired renal function may be at greater risk of toxicities.

Monitoring parameters:

• Monitor for signs & symptoms of hypersensitivity.

How to administer Ceretec (Technetium TC 99m Exametazime)?

IV:

• Before administration, ensure adequate hydration and also after administration.
• Instruct patient to void within 2 hours after administration to minimize radiation exposure.
• Patients should void frequently to minimize kidney and bladder exposure.

Leukocyte-labeled scintigraphy:

• Administer using a 19-gauge needle as soon as possible (preferably within 20 minutes but no later than 1 hour) after preparation of the Tc 99m labeled leukocyte suspension.

Radiopharmaceutical.

• Use of appropriate precautions  and equipments is recommended for handling and disposal. Ensure adequate hydration before and after administration.

Mechanism of action of Ceretec (Technetium TC 99m Exametazime):

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

Distribution:

• Distributes to brain, muscle, and soft tissue

Half-life elimination:

• Physical: ~6 hours

Excretion:

• Feces (~50%);
• Urine (~40%)

International Brand Names of Technetium Tc-99m exametazime:

• Ceretec
• Drax Exametazime
• Brain-Spect
• Cerestab
• Ceretec
• Leuco-Scint

Technetium Tc-99m exametazime Brand Names in Pakistan:

It may be available in specialized centers in Pakistan.