Technescan PYP

Name: Technescan PYP

Uses of Technescan PYP

  • It is used with a special imaging test.

What do I need to tell my doctor BEFORE I take Technescan PYP?

  • If you have an allergy to technetium Tc 99m pyrophosphate or any other part of Technescan PYP (technetium tc 99m pyrophosphate).
  • If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
  • If you are breast-feeding or plan to breast-feed.

This medicine may interact with other drugs or health problems.

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this medicine with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

How is this medicine (Technescan PYP) best taken?

Use Technescan PYP as ordered by your doctor. Read all information given to you. Follow all instructions closely.

  • It is given as a shot into a vein.

What do I do if I miss a dose?

  • Call your doctor to find out what to do.

If OVERDOSE is suspected

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Physical characteristics

Technetium Tc 99m decays by isomeric transition with a physical half-life of 6.02 hours.1 The principal photon that is useful for detection and imaging is listed in Table 1.

Table 1. Principal Radiation Emission Data1
 Radiation  Mean Percent/Disintegration  Energy (keV)
 Gamma-2  89.07  140.5

The specific gamma ray constant for technetium Tc 99m is 0.78 R/mCi-hr at 1 cm. The first half-value thickness of lead (Pb) for technetium Tc 99m is 0.017 cm. A range of values for the relative attenuation of the radiation emitted by this radionuclide that results from interposition of various thicknesses of Pb is shown in Table 2. For example, the use of 0.25 cm of Pb will decrease the external radiation exposure by a factor of about 1000.

Table 2. Radiation Attenuation by Lead Shielding
 Shield
Thickness (Pb) cm
 Coefficient
of Attenuation
 0.017
0.08
0.16
0.25
0.33
 0.5
10-1
10-2
10-3
10-4

To correct for physical decay of this radionuclide, the fractions that remain at selected time intervals after the time of calibration are shown in Table 3.

Table 3. Physical Decay Chart; Technetium Tc 99m, Half-Life 6.02 Hours
 

*Calibration Time

 Hours  Fraction
Remaining
 Hours  Fraction
Remaining
 0*  1.000  7  0.447
 1  0.891  8  0.398
 2  0.794  9  0.355
 3  0.708  10  0.316
 4  0.631  11  0.282
 5  0.562  12  0.251
 6  0.501    
1 Kocher, David C., Radioactive Decay Data Tables, DOE/TIC-11026, 108 (1981).

Contraindications

None known.

Dosage and administration

Bone and Cardiac 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.

Blood Pool Imaging

The recommended adult dose of TechneScan PYP is one-third (0.33) to the entire vial contents, followed by 555 to 740 megabecquerels (15 to 20 millicuries) of sodium pertechnetate Tc 99m. Cardiac imaging should be done 10 minutes following the administration of sodium pertechnetate Tc 99m (in vivo method) or Tc 99m labeled red blood cells (modified in vivo/in vitro method) utilizing a scintillation camera interfaced to an electrocardiographic gating device.

In Vivo Method: TechneScan PYP is reconstituted with sterile, non-pyrogenic normal saline containing no preservatives. The patient dose is administered intravenously 15 to 30 minutes prior to the intravenous administration of 555 to 740 megabecquerels (15 to 20 millicuries) of sodium pertechnetate Tc 99m. TechneScan PYP should be injected by direct venipuncture. Heparinized catheter systems should be avoided.

Modified In Vivo/In Vitro Method Using Acid-Citrate-Dextrose (ACD): TechneScan PYP is reconstituted with sterile, non-pyrogenic normal saline containing no preservatives, and the patient dose is administered intravenously. An intravenous line containing a 3-way stopcock is inserted in a large peripheral vein and kept patent with a continuous drip of sterile, non-pyrogenic normal saline containing no preservatives. Thirty minutes after TechneScan PYP injection, the infusion line and stopcock are cleared by withdrawing and discarding approximately 5 milliliters of whole blood. Immediately following, approximately 5 milliliters of whole blood are withdrawn into a syringe containing 1 milliliter preservative-free acid-citrate-dextrose (ACD) and 555 to 740 megabecquerels (15 to 20 millicuries) of sodium pertechnetate Tc 99m. The stopcock is then turned, residual blood is flushed from the intravenous line, and the normal saline flow is readjusted. The syringe is gently rotated to mix and allowed to incubate at room temperature for 10 minutes prior to injection via the 3-way stopcock.

Modified In Vivo/In Vitro Method Using Heparin: TechneScan PYP is reconstituted with sterile, non-pyrogenic normal saline containing no preservatives, and the patient dose is administered intravenously. An infusion set fitted with a 3-way stopcock is placed in a large peripheral vein, and the intravenous line is heparinized with a saline solution containing 5 to 10 units preservative-free heparin per milliliter. Thirty minutes after TechneScan PYP injection, 3 milliliters of blood are withdrawn into a syringe containing 555 to 740 megabecquerels (15 to 20 millicuries) of sodium pertechnetate Tc 99m. Anticoagulation of the blood is provided by residual heparin in the intravenous line. The syringe is gently rotated to mix and allowed to incubate at room temperature for 10 minutes prior to injection via the 3-way stopcock.

Parenteral drug products should be visually inspected for particulate matter and discoloration prior to administration whenever solution and container permit. Do not use if contents are turbid.

Radiation dosimetry

Method of Calculation: The following radiation absorbed dose values were obtained using the Medical Internal Radiation Dose Committee (MIRD) Schema.

Bone and Cardiac Imaging

Maximum Dose: 555 megabecquerels (15 millicuries) administered intravenously. The effective half-life was assumed to be the physical half-life for all calculated values. About 50% of each dose of Technetium Tc 99m Pyrophosphate Injection is retained in skeleton, and about 50% is excreted into the bladder. The estimated absorbed radiation doses to an average patient (70 kg) from an intravenous injection of a maximum dose of 555 megabecquerels (15 millicuries) of Technetium Tc 99m Pyrophosphate Injection are shown in Table 4.

Table 4. Absorbed Radiation Doses (Bone and Cardiac Imaging)
 

*Dose at point of highest uptake may be a factor of 10 higher.

 Tissue  Technetium Tc 99m Pyrophosphate Injection
 mGy/555 MBq  rads/15 mCi
 Skeleton*  5.9  0.59
 Bone Marrow  4.2  0.42
 Kidneys  21.0  2.10
 Total Body  1.3  0.13
 Bladder    
    2-hr. void  14.6  1.46
    4.8-hr. void  34.5  3.45
 Testes    
    2-hr. void  1.5  0.15
    4.8-hr. void  2.3  0.23
 Ovaries    
    2-hr. void  1.4  0.14
    4.8-hr. void  2.3  0.23
 Heart    
 Normal  1.1  0.11
 Impaired  2.2  0.22

Blood Pool Imaging

The estimated absorbed radiation doses to an average patient (70 kg) from administration of 740 megabecquerels (20 millicuries) of sodium pertechnetate Tc 99m, 30 minutes after the intravenous administration of TechneScan PYP are shown in Table 5.

Table 5. Absorbed Radiation Doses2 (Blood Pool Imaging)*

*Assumes non-resting state, with 75% of the sodium pertechnetate Tc 99m labeling red blood cells and the other 25% remaining as pertechnetate.

**Assumes no initial uptake in spleen.

 

2Data supplied by Oak Ridge Associated Universities, Radiopharmaceutical Internal Dose Information Center, 1986.

 
Tissue
 Sodium Pertechnetate Tc 99m
30 min. Post TechneScan PYP Administration
 mGy/740 MBq  rads/20 mCi
 Bladder Wall  6.8  0.68
 Ovaries  4.6  0.46
 Testes  2.6  0.26
 Red Marrow  3.8  0.38
 Spleen**  3.0  0.30
 Blood  10.2  1.02
 Total Body  3.0  0.30
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