Indium In-111 pentetreotide is an agent for the scintigraphic localization of primary and metastatic neuroendocrine tumors bearing somatostatin receptors.
DOSAGE AND ADMINISTRATION
Before administration, a patient should be well hydrated. After administration, the patient must be encouraged to drink fluids liberally. Elimination of extra fluid intake will help reduce the radiation dose by flushing out unbound, labelled pentetreotide by glomerular filtration. It is also recommended that a mild laxative (e.g., bisacodyl or lactulose) be given to the patient starting the evening before the radioactive drug is administered, and continuing for 48 hours. Ample fluid uptake is necessary during this period as a support both to renal elimination and the bowel-cleansing process. In a patient with an insulinoma, bowel-cleansing should be undertaken only after consultation with an endocrinologist.
The recommended intravenous dose for planar imaging is 111 MBq (3.0 mCi) of indium In-111 pentetreotide prepared from an Octreoscan kit. The recommended intravenous dose for SPECT imaging is 222 MBq (6.0 mCi) of indium In-111 pentetreotide.
The dose should be confirmed by a suitably calibrated radioactivity ionization chamber immediately before administration.
As with all intravenously administered products, Octreoscan should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit. Preparations containing particulate matter or discoloration should not be administered. They should be disposed of in a safe manner, in compliance with applicable regulations.
Aseptic techniques and effective shielding should be employed in withdrawing doses for administration to patients. Waterproof gloves should be worn during the administration procedure.
Do not administer Octreoscan in TPN solutions or through the same intravenous line.
The estimated radiation doses2 to the average adult (70 kg) from intravenous administration of 111 MBq (3 mCi) and 222 MBq (6 mCi) are presented in Table 4. These estimates were calculated by Oak Ridge Associated Universities using the data published by Krenning, et al.3
2 Values listed include a correction for a maximum of 0.1% indium In-114m radiocontaminant at calibration.
3 E.P. Krenning, W.H. Bakker, P.P.M. Kooij, W.A.P. Breeman, H.Y. Oei, M. de Jong, J.C. Reubi, T.J. Visser, C. Bruns, D.J. Kwekkeboom, A.E.M. Reijs, P.M. van Hagen, J.W. Koper, and S.W.J. Lamberts, “Somatostatin Receptor Scintigraphy with Indium-111-DTPA-D-Phe-1-Octreotide in Man: Metabolism, Dosimetry and Comparison with Iodine-123-Try-3-Octreotide,” The Journal of Nuclear Medicine, Vol. 33, No. 5, May 1992, pp. 652-658.
Table 4. Estimated Absorbed Radiation Doses after Intravenous Administration of Indium In-111 Pentetreotide* to a 70 kg Patient
|mGy/111 MBq||rads/3 mCi||mGy/222 MBq||rads/6 mCi|
|Urinary Bladder Wall||30.24||3.02||60.48||6.05|
|Upper Large Intestine||5.80||0.58||11.59||1.16|
|Lower Large Intestine||7.73||0.77||15.46||1.55|
|mSv/111 MBq||rem/3 mCi||mSv/222 MBq||rem/6 mCi|
|Effective Dose† Equivalent||13.03||1.30||26.06||2.61|
* Assumes 4.8 hour voiding interval and International Commission on Radiological Protection (ICRP) 30 model for the gastrointestinal tract calculations.
† Estimated according to ICRP Publication 53.
The Octreoscan kit (NDC 69945-050-40) is supplied with the following components:
Before lyophilization, sodium hydroxide or hydrochloric acid may have been added for pH adjustment. The vial contents are sterile and nonpyrogenic. No bacteriostatic preservative is present.
- A 10-mL Octreoscan Reaction Vial which contains a lyophilized mixture of:
- 10 μg pentetreotide [N-(diethylenetriamine-N,N,N',N”-tetraacetic acid-N”-acetyl)-D-phenylalanyl-L-hemicystyl-L-phenylalanyl-D-tryptophyl-L-lysyl-Lthreonyl- L-hemicystyl-L-threoninol cyclic (2→7) disulfide], (also known as octreotide DTPA),
- 2.0 mg gentisic acid [2, 5-dihydroxybenzoic acid],
- 4.9 mg trisodium citrate, anhydrous,
- 0.37 mg citric acid, anhydrous, and
- 10.0 mg inositol.
- A 10-mL vial of Indium In-111 Chloride Sterile Solution, which contains 1.1 mL or 111 MBq/mL (3.0 mCi/mL) indium In-111 chloride in 0.02 N HCl at time of calibration. The vial also contains ferric chloride at a concentration of 3.5 μg/mL (ferric ion, 1.2 μg/mL). The vial contents are sterile and nonpyrogenic. No bacteriostatic preservative is present.
In addition, the kit also contains the following items: (1) a 25 G x 5/8” needle (B-D, Monoject) used to transfer Indium In-111 Chloride Sterile Solution to the Octreoscan Reaction Vial, (2) pressure sensitive label, and (3) a package insert.
The Octreoscan kit should be stored refrigerated at 2° to 8°C (36° to 46°F). After reconstitution, store at or below 25°C (77°F). Indium In-111 pentetreotide must be used within six hours of preparation.
Manufactured by: Curium US LLC, Maryland Heights, MO 63043. Revised: Dec 2018