Technescan Pyp
(Technetium Tc 99m Pyrophosphate)Technescan Pyp Prescribing Information
Technetium Tc 99m Pyrophosphate Injection is a skeletal imaging agent used to demonstrate areas of altered osteogenesis, and a cardiac imaging agent used as an adjunct in the diagnosis of acute myocardial infarction.
As an adjunct in the diagnosis of confirmed myocardial infarction (ECG and serum enzymes positive), the incidence of false negative images has been found to be 6%. False negative images can also occur if made too early in the evolutionary phase of the infarct or too late in the resolution phase. In a limited study involving 22 patients in whom the ECG was positive and serum enzymes questionable or negative, but in whom the final diagnosis of acute myocardial infarction was made, the incidence of false negative images was 23%. The incidence of false positive images has been found to be 7 to 9%. False positive images have been reported following coronary by-pass graft surgery, in unstable angina pectoris, old myocardial infarcts and in cardiac contusions.
Technescan PYP is a blood pool imaging agent which may be used for gated blood pool imaging and for the detection of sites of gastrointestinal bleeding. When administered intravenously 15 to 30 minutes prior to intravenous administration of sodium pertechnetate Tc 99m for in vivo red blood cell labeling, approximately 75% of the injected activity remains in the blood pool. The modified in vivo/in vitro red blood cell labeling method may also be used for blood pool imaging.
The recommended adult doses of Technetium Tc 99m Pyrophosphate Injection are:
| Indication | Doses as Technetium Tc 99 | Fraction of Vial Contents Required |
| Skeletal Imaging | 185 to 555 megabecquerels (5 to 15 mCi) | 0.07 to 0.91 |
| Cardiac Imaging | 370 to 555 megabecquerels (10 to 15 mCi) | 0.26 to 0.45 |
Technetium Tc 99m Pyrophosphate Injection is injected intravenously over a 10- to 20-second period. For optimal results, bone imaging should be done one to six hours following administration. Cardiac imaging should be done 60 to 90 minutes following administration. The acute myocardial infarct can be visualized from 24 hours to nine days following onset of symptoms, with maximum localization at 48 to 72 hours. Cardiac imaging should be done with a gamma scintillation camera. It is recommended that images be made of the anterior, left anterior oblique and left lateral projections.
The patient dose should be measured by a suitable radioactivity calibration system immediately prior to administration. It is also recommended that the radiochemical purity be checked prior to administration.
None known.
Several adverse reactions due to the use of Technetium Tc 99m Pyrophosphate Injection have been reported. These were usually flushing, hypotension, fever, chills, nausea, vomiting and dizziness, as well as hypersensitivity reactions such as itching and various skin rashes.
The biodistribution of technetium Tc 99m pyrophosphate may be altered in the presence of high levels of certain cations (iron, calcium, and aluminum). This may result in reduced uptake of radionuclide in the skeleton and increased extraosseal uptake, which may potentially degrade imaging quality. In patients with high levels of these cations caused by concomitant medications, particularly patients receiving iron infusions, consider performing an imaging study with technetium Tc 99m pyrophosphate injection once the cation levels have normalized (e.g., after 3 to 5 half-lives of the cation). (See
Reports indicate impairment of brain images using sodium pertechnetate Tc 99m, which have been preceded by a bone image. The impairment may result in false positives or false negatives. It is recommended, where feasible, that brain imaging precede bone imaging procedures.
Preliminary reports indicate impairment of blood pool images in patients receiving sodium heparin for anticoagulant therapy. This is characterized by a reduction in the amount of injected radioactivity remaining in the blood pool.
Technescan PYP should be injected by direct venipuncture. Heparinized catheter systems should be avoided.
Technescan™ PYP™ (Kit for the Preparation of Technetium Tc 99m Pyrophosphate Injection) is a sterile, non-pyrogenic, diagnostic radiopharmaceutical suitable for intravenous administration after reconstitution with sterile sodium pertechnetate Tc 99m injection or sterile 0.9% sodium chloride injection.
Each 10 milliliter reaction vial contains 11.9 milligrams sodium pyrophosphate, 3.2 milligrams (minimum) stannous chloride (SnCl
2•2H
2O) and 4.4 milligrams (maximum) total tin expressed as stannous chloride (SnCl
2•2H
2O) in lyophilized form under an atmosphere of nitrogen. Prior to lyophilization the pH is adjusted with hydrochloric acid. The pH of the reconstituted drug is between 4.5 and 7.5. No bacteriostatic preservative is present.
The precise structures of the stannous-pyrophosphate and technetium-stannous-pyrophosphate complexes are not known at this time.