Sodium Iodide I 123- Sodium Iodide I 123 capsule, Gelatin Coated prescribing information
INDICATION AND USE
Administration of Sodium Iodide I 123 is indicated as a diagnostic procedure to be used in evaluating thyroid function and/or morphology.
DOSAGE AND ADMINISTRATION
The recommended oral dose for the average patient (70 kg) is 3.7 to 14.8 MBq (100-400 µCi). The lower part of the dosage range 3.7 MBq (100 µCi) is recommended for uptake studies alone, and the higher part 14.8 MBq (400 µCi) for thyroid imaging. The determination of I 123 concentration in the thyroid gland may be initiated at six hours after administering the dose and should be measured in accordance with standardized procedures.
The patient dose should be measured by a suitable radioactive calibration system immediately prior to administration. The capsules can be utilized up to thirty (30) hours after calibration time and date. Thereafter, discard the capsules in accordance with standard safety procedures. The user should wear waterproof gloves at all times when handling the capsules or container.
Radiation Dosimetry
The estimated absorbed radiation doses to several organs of an average patient (70 kg) from oral administration of the maximum dose of 14.8 MBq (400 µCi) of I 123 are shown in Table 4 for thyroid uptakes of 5, 15, and 25%. For comparison at these three values of thyroid uptake, the estimated radiation doses from doses of 3.7 MBq (100 µCi) I 131, also used as thyroid imaging agent, are also included.
| •Concentration at Time of Calibration: 97% I 123, 2.9% I 125, 0.1% Te 121 Concentration at Time of Expiry: 87.2% I 123, 12.4% I 125, 0.4% Te 121 All Iodine Kinetics treated as in MIRD Dose Estimate Report 5. Bladder voiding interval, 4.8 hours. Tellurium 121 dosimetry taken from ICRP 30. | |||||||
Target Organ | Maximum Thyroid Uptake (%) | Estimated Radiation Absorbed Doses | |||||
I 123 mGy/14.8 MBq (rads/400 µCi) | I 131 mGy/3.7 MBq (rads/100 µCi) | ||||||
TOC | TOE | ||||||
Thyroid | 5 | 25 | (2.5) | 75 | (7.5) | 260 | (26) |
15 | 77 | (7.7) | 230 | (23) | 780 | (78) | |
25 | 130 | (13) | 410 | (41) | 1300 | (130) | |
Liver | 5 | 0.089 | (0.0089) | 0.13 | (0.013) | 0.16 | (0.016) |
15 | 0.10 | (0.010) | 0.18 | (0.018) | 0.28 | (0.028) | |
25 | 0.11 | (0.011) | 0.24 | (0.024) | 0.41 | (0.041) | |
Ovaries | 5 | 0.18 | (0.018) | 0.19 | (0.019) | 0.18 | (0.018) |
15 | 0.17 | (0.017) | 0.18 | (0.018) | 0.18 | (0.018) | |
25 | 0.16 | (0.016) | 0.18 | (0.018) | 0.17 | (0.017) | |
Red Marrow | 5 | 0.12 | (0.012) | 0.16 | (0.016) | 0.15 | (0.015) |
15 | 0.12 | (0.012) | 0.18 | (0.018) | 0.21 | (0.021) | |
25 | 0.13 | (0.013) | 0.19 | (0.019) | 0.27 | (0.027) | |
Stomach Wall | 5 | 0.96 | (0.096) | 0.98 | (0.098) | 1.7 | (0.17) |
15 | 0.89 | (0.089) | 0.91 | (0.091) | 1.5 | (0.15) | |
25 | 0.82 | (0.082) | 0.85 | (0.085) | 1.4 | (0.14) | |
Small Intestine | 5 | 0.70 | (0.070) | 0.71 | (0.071) | 1.2 | (0.12) |
15 | 0.65 | (0.065) | 0.67 | (0.067) | 1.1 | (0.11) | |
25 | 0.60 | (0.060) | 0.62 | (0.062) | 0.99 | (0.099) | |
Testes | 5 | 0.076 | (0.0076) | 0.089 | (0.0089) | 0.12 | (0.012) |
15 | 0.072 | (0.0072) | 0.087 | (0.0087) | 0.12 | (0.012) | |
25 | 0.068 | (0.0068) | 0.085 | (0.0085) | 0.12 | (0.012) | |
Bladder | 5 | 1.7 | (0.17) | 1.7 | (0.17) | 2.9 | (0.29) |
15 | 1.6 | (0.16) | 1.6 | (0.16) | 2.7 | (0.27) | |
25 | 1.4 | (0.14) | 1.5 | (0.15) | 2.4 | (0.24) | |
Skeleton | 5 | 0.11 | (0.011) | 0.16 | (0.016) | 0.12 | (0.012) |
15 | 0.12 | (0.012) | 0.18 | (0.018) | 0.18 | (0.018) | |
25 | 0.14 | (0.014) | 0.21 | (0.021) | 0.24 | (0.024) | |
Total Body | 5 | 0.11 | (0.011) | 0.16 | (0.016) | 0.24 | (0.024) |
15 | 0.14 | (0.014) | 0.25 | (0.025) | 0.47 | (0.047) | |
25 | 0.17 | (0.017) | 0.35 | (0.035) | 0.70 | (0.070) | |
CONTRAINDICATIONS
To date there are no known contraindications to the use of Sodium Iodide I 123 capsules.
ADVERSE REACTIONS
Although rare, reactions associated with the administration of Sodium Iodide isotopes for diagnostic use include, in decreasing order of frequency, nausea, vomiting, chest pain, tachycardia, itching skin, rash and hives.
DESCRIPTION
Sodium Iodide I 123 (Na 123 I) for diagnostic use is supplied in capsules for oral administration. The capsules are available in strengths of 3.7 and 7.4 megabecquerels (MBq) (100 and 200 μCi) I 123 at time of calibration. Each capsule contains 0.3 µg - 3 µg Sodium Thiosulfate as a stabilizer.
The radionuclidic composition at calibration is not less than 97.0 percent I 123, not more than 2.9 percent I 125 and not more than 0.1 percent all others (I 121 or Te 121.) The radionuclidic composition at expiration time is not less than 87.2 percent I 123, not more than 12.4 percent I 125 and not more than 0.4 percent all others. The ratio of the concentration of I 123 and I 125 changes with time. Graph 1 shows the maximum concentration of each as a function of time.
Physical Characteristics
Sodium Iodide I 123 decays by electron capture with a physical half-life of 13.2 hours. The photon that is useful for detection and imaging studies is listed in Table 1 .
| 1 Kocher, David C., Radioactive Decay Data Tables, DOE/TIC-11026, 122, (1981) | ||
Radiation | Mean %/Disintegration | Mean Energy (keV) |
Gamma-2 | 83.4 | 159 |
External Radiation
The specific gamma ray constant for I 123 is 1.6 R/hr-mCi at 1 cm. The first half value thickness of lead (Pb) for I 123 is 0.005 cm. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from the interposition of various thicknesses of Pb is shown in Table 2 . For example, the use of 1.63 cm of lead will decrease the external radiation exposure by a factor of about 1,000.
| 2 Shleien, Bernard, The Health Physics and Radiological Health Handbook, Table 6.1.2, 169, (1992) | |
Shield Thickness (Pb), cm | Coefficient of Attenuation |
0.036 | 0.5 |
0.120 | 10 -1 |
0.240 | 10 -2 |
0.358 | 10 -3 |
0.477 | 10 -4 |
Note that these estimates of attenuation do not take into consideration the presence of contaminants.
To correct for physical decay of I 123, the fractions that remain at selected intervals after the time of calibration are shown in Table 3 .
| •Time of Calibration | |||||
Hours | Fraction Remaining | Hours | Fraction Remaining | ||
0• | 1.000 | 18 | .389 | ||
3 | .854 | 21 | .332 | ||
6 | .730 | 24 | .284 | ||
9 | .623 | 27 | .242 | ||
12 | .535 | 30 | .207 | ||
15 | .455 | ||||
CLINICAL PHARMACOLOGY
Sodium Iodide I 123 is readily absorbed from the upper gastrointestinal tract. Following absorption, the iodide is distributed primarily within the extracellular fluid of the body. It is trapped and organically bound by the thyroid and concentrated by the stomach, choroid plexus and salivary glands. It is excreted by the kidneys.
The fraction of the administered dose which is accumulated in the thyroid gland may be a measure of thyroid function in the absence of unusually high or low iodine intake or administration of certain drugs which influence iodine accumulation by the thyroid gland. Accordingly, the patient should be questioned carefully regarding previous medication and/or procedures involving radiographic media. Normal subjects can accumulate approximately 10-50% of the administered iodine dose in the thyroid gland, however, the normal and abnormal ranges are established by individual physician's criteria. The mapping (imaging) of Sodium Iodide I 123 distribution in the thyroid gland may provide useful information concerning thyroid anatomy and definition of normal and/or abnormal functioning of tissue within the gland.
HOW SUPPLIED
Sodium Iodide I 123 is supplied as capsules for oral administration in strengths of 3.7 MBq (100 µCi) and 7.4 MBq (200 µCi) at time of calibration. Each gelatin capsule contains 0.45 - 0.65 g of sucrose. The capsules are packaged in plastic vials containing either one or five capsules of a single strength per vial. The plastic vial is packaged in a lead shield with a label identical to that affixed to the plastic vial. A package insert is supplied with each lead shield.
The -I (Iodine) content for a 100 µCi capsule is 5.2 ng and the -I content for a 200 µCi capsule is 10.4 ng at TOC.
Dispense and preserve capsules in well-closed containers that are adequately shielded. Store at room temperature, below 86°F.
The contents of the capsules are radioactive. Adequate shielding and handling precautions must be maintained.
THIS PACKAGE INSERT ISSUED APRIL 2018
Cardinal Health Denver, CO 80011 (303) 343-6800
Sodium Iodide I 123 1-020-16