ction with exercise or pharmacologic stress. ( 1 ) localization of sites of parathyroid hyperactivity pre- and post-operatively in patients with elevated serum calcium and parathyroid hormone levels. ( 1 )

, bronchoconstriction, and cerebrovascular events. perform pharmacologic stress when indicated and in accordance with the pharmacologic stress agent’s prescribing information. 5.3 radiation risks thallous chloride tl 201 contributes to the cumulative radiation exposure. when considering administration of thallous chloride tl 201 injection to women of child-bearing potential, consider the radiation risks for a fetus [see use in specific populations ( 8.1 )] . use the lowest dose necessary for imaging and ensure safe handling to protect the patient and health care worker [see dosage and administration ( 2.1 )( 2.5 )]. 5.4 risk of extravasation and tissue damage inject thallous chloride tl 201 strictly intravenously to avoid local tissue accumulation and irradiation. confirm intravenous patency before injection [see adverse reactions ( 6.3 )].

to 74 mbq (1 to 2 mci) administered intravenously spect: 74 to 111 mbq (2 to 3 mci) administered intravenously parathyroid hyperactivity localization planar or spect: 75 to 130 mbq (2 to 3.5 mci) administered intravenously 2.3 drug administration and imaging for resting myocardial studies, begin imaging 10 to 20 minutes after injection of thallous chloride tl 201. myocardial-to-background ratios are improved when patients are injected upright and in the fasting state; the upright position reduces the hepatic and gastric thallium tl-201 concentration. for exercise stress testing administer thallous chloride tl 201 injection at the start of a period of maximum stress which is sustained for approximately 30 seconds after injection. begin imaging within ten minutes after administration to obtain maximum target-to-background ratios. within two hours after the completion of the stress testing the target-to-background ratios may decrease in lesions that are attributable to transient ischemia. for localization of parathyroid hyperactivity, administer thallous chloride tl 201 injection before, with or after a minimal dose of a thyroid imaging agent such as sodium pertechnetate tc 99m or sodium iodide i-123 to enable thyroid subtraction imaging. 2.4 radiation dosimetry the estimated absorbed radiation doses at calibration time to a 70 kg patient from an intravenous injection of thallous chloride tl 201 are shown in table 1. the estimates were calculated based on human data from krahwinkel et al. 1 and thomas et al. 2 assumed percentages of 98.3% 201 tl, 0.3% 200 tl, 1.2% 202 tl, and 0.2% 203 pb. the effective dose was calculated using icrp 103 tissue weighting factors and assumptions on the biodistribution data based on data from krahwinkel et al. and thomas et al. table 1. radiation dose estimates for thallous chloride tl 201 (includes contaminants) organ estimated radiation dose mgy/mbq rad/mci adrenals 6.33e-02 2.34e-01 brain 5.68e-02 2.10e-01 breasts 3.39e-02 1.25e-01 gb wall 8.31e-02 3.07e-01 lli wall 2.96e-01 1.09e+00 small intestine 3.79e-01 1.40e+00 stomach 1.71e-01 6.34e-01 uli wall 2.97e-01 1.10e+00 heart wall 2.47e-01 9.14e-01 kidneys 4.10e-01 1.52e+00 liver 9.39e-02 3.47e-01 lungs 4.73e-02 1.75e-01 muscle 4.59e-02 1.70e-01 ovaries 1.02e-01 3.76e-01 pancreas 7.52e-02 2.78e-01 red marrow 4.44e-02 1.64e-01 bone surfaces 9.37e-02 3.47e-01 skin 3.16e-02 1.17e-01 spleen 1.66e-01 6.14e-01 testes 2.09e-01 7.73e-01 thymus 4.60e-02 1.70e-01 thyroid 5.42e-01 2.00e+00 urinary bladder wall 6.25e-02 2.31e-01 uterus 8.63e-02 3.19e-01 total body effective dose 5.77e-02 0.145msv/mbq 2.14e-01 0.535rem/mci 2.5 drug handling do not use this drug after six (6) days from the calibration date, or nine (9) days from date of manufacture, whichever comes first. limit the use of this drug, to physicians who are qualified by training and experience in the safe use and handling of radionuclides. wear waterproof gloves during the handling procedures. aseptically withdraw the material for use with a shielded sterile syringe. measure the patient dose with a suitable radioactivity calibration system immediately prior to administration. visually inspect the drug for particulate matter and discoloration prior to administration, whenever solution and container permit. do not use if contents are turbid. minimize radiation exposure to the patient and ensure minimum radiation exposure to occupational workers.

ble thyroid subtraction imaging.

1.70e-01 ovaries 1.02e-01 3.76e-01 pancreas 7.52e-02 2.78e-01 red marrow 4.44e-02 1.64e-01 bone surfaces 9.37e-02 3.47e-01 skin 3.16e-02 1.17e-01 spleen 1.66e-01 6.14e-01 testes 2.09e-01 7.73e-01 thymus 4.60e-02 1.70e-01 thyroid 5.42e-01 2.00e+00 urinary bladder wall 6.25e-02 2.31e-01 uterus 8.63e-02 3.19e-01 total body effective dose 5.77e-02 0.145msv/mbq 2.14e-01 0.535rem/mci

( 5 )] . 6.2 common reactions the most frequently reported reactions were itching, nausea, vomiting, mild diarrhea, tremor, shortness of breath, chills, fever, conjunctivitis, sweating, and blurred vision. 6.3 postmarketing experience the following adverse reactions have been identified during post-approval use of thallous chloride tl 201. because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure: injection site reactions and extravasation of tl-201 have been reported: burning, pain, redness, swelling, warmth, and, in one case, tissue damage with chronic ulcer formation

v (0.1 rem) to the infant. 8.4 pediatric use safety and effectiveness of thallous chloride tl 201 injection in pediatric patients have not been established. 8.6 females of reproductive potential assess the pregnancy status of women of childbearing potential prior to performing imaging procedures with thallous chloride tl 201 injection [see warnings and precautions ( 5.3 )] .

tration by normal myocardium occurring at about 10 minutes. it will, in addition, localize in parathyroid adenomas; it is not specific since it will localize to a lesser extent in sites of parathyroid hyperplasia and other abnormal tissues such as thyroid adenoma, neoplasia (e.g., parathyroid carcinoma) and sarcoid. biodistribution is generally proportional to organ blood flow at the time of injection. blood clearance of thallous chloride tl 201 is primarily by the myocardium, thyroid, liver, kidneys and stomach with the remainder distributing fairly uniformly throughout the body. the dosimetry data in table 1 reflect this distribution pattern and are based on a biological half-life of 2.4 days. thallous chloride tl 201 is excreted slowly and to an equal extent in both feces and urine. five minutes after intravenous administration only 5 to 8 percent of injected activity remained in the blood. a biexponential disappearance curve was obtained, with 91.5 percent of the blood radioactivity disappearing with a half-time of about 5 minutes. the remainder had a half-time of about 40 hours. approximately 4 to 8 percent of the injected dose was excreted in the urine in the first 24 hours. the whole body disappearance half-time was 9.8 ± 2.5 days. kidney concentration was found to be about 3 percent of the injected activity and the testicular content was 0.15 percent. net thyroid activity was determined to be only 0.2 percent of the injected dose, and the activity disappeared in 24 hours. from anterior and posterior whole-body scans, it was determined that about 45 percent of the injected dose was in the large intestines and contiguous structures (liver, kidneys, abdominal musculature).

cted activity remained in the blood. a biexponential disappearance curve was obtained, with 91.5 percent of the blood radioactivity disappearing with a half-time of about 5 minutes. the remainder had a half-time of about 40 hours. approximately 4 to 8 percent of the injected dose was excreted in the urine in the first 24 hours. the whole body disappearance half-time was 9.8 ± 2.5 days. kidney concentration was found to be about 3 percent of the injected activity and the testicular content was 0.15 percent. net thyroid activity was determined to be only 0.2 percent of the injected dose, and the activity disappeared in 24 hours. from anterior and posterior whole-body scans, it was determined that about 45 percent of the injected dose was in the large intestines and contiguous structures (liver, kidneys, abdominal musculature).

te regulations of the government agency authorized to license the use of this radionuclide.