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OctreoScan Dosage

Generic name: INDIUM IN-111 PENTETREOTIDE 10ug in 1mL; INDIUM CHLORIDE IN-111 3mCi in 1mL
Dosage form: injection
Drug class: Diagnostic radiopharmaceuticals

Medically reviewed by Last updated on Feb 21, 2022.

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 mCi) of Indium In 111 Pentetreotide Injection prepared from an Octreoscan kit. The recommended intravenous dose for SPECT imaging is 222 MBq (6 mCi) of Indium In 111 Pentetreotide Injection.

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.

Radiation Dosimetry

The estimated radiation doses1 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.2

Table 4. Estimated Absorbed Radiation Doses after Intravenous Administration of Indium In 111 Pentetreotide*to a 70 kg Patient
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.
Organ mGy/111 MBq rads/3 mCi mGy/222 MBq rads/6 mCi
Kidneys 54.16 5.42 108.32 10.83
Liver 12.15 1.22 24.31 2.43
Spleen 73.86 7.39 147.73 14.77
Uterus 6.34 0.63 12.67 1.27
Ovaries 4.89 0.49 9.79 0.98
Testes 2.90 0.29 5.80 0.58
Red Marrow 3.46 0.35 6.91 0.69
Urinary Bladder Wall 30.24 3.02 60.48 6.05
GI Tract
Stomach Wall 5.67 0.57 11.34 1.13
Small Intestine 4.78 0.48 9.56 0.96
Upper Large Intestine 5.80 0.58 11.59 1.16
Lower Large Intestine 7.73 0.77 15.46 1.55
Adrenals 7.55 0.76 15.11 1.51
Thyroid 7.43 0.74 14.86 1.49
mSv/111 MBq rem/3 mCi mSv/222 MBq rem/6 mCi
Effective DoseEquivalent 13.03 1.30 26.06 2.61

Values listed include a correction for a maximum of 0.1% indium In-114m radiocontaminant at calibration.
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.

Further information

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