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Particle number determination

Particle number determination. Manipulating the conditions. Particle numbers. Reduced numbers of 99mTc MAA particles should be considered for patients with pulmonary hypertension, pneumonectomy, or right-to-left shunting, and in infants and children.

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Particle number determination

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  1. Particle number determination Manipulating the conditions Frank P. Dawry

  2. Particle numbers Reduced numbers of 99mTc MAA particles should be considered for patients with pulmonary hypertension, pneumonectomy, or right-to-left shunting, and in infants and children. Frank P. Dawry

  3. The number of particles available per dose of Tc-99m MAA will vary depending on the physical decay that has occurred The number of particles in any dose and volume to be administered may be calculated as follows: Assume the average number of particles per vial = 6.0 x 106. If: VA = volume to be administered in ml D = desired dose to be administered (mCi) C = concentration of Tc-99m to be added to the reaction vial. (mCi/ml) Fr = fraction of Tc-99m remaining after the time of calibration – taken from decay factor chart P = number of particles in dose to be administered VTC = volume of solution added to reaction vial Then: VA = __D __ and P = _Va_ x 6.0 x 106 C X Fr VTC Frank P. Dawry

  4. Particle Calculations • Determine the volume dose to be administered to the patient: specific concentration = activity/volume required volume = activity desired/specific concentration or ml = mCi/mCi/ml • Calculate the particle concentration of the reconstituted kit: total particles in kit/ml added to kit = particles/ml • Calculate the particles per dose: particles/1.0 ml = particles in patient dose/ml of patient dose (particle concentration in particles/ml)(ml dose volume) = particles in patient dose Frank P. Dawry

  5. Particle number determination • Have: • 30 mCi 99mTc in 1.3 ml • Calibration time = 12:00 • Wanted Dose: • 200, 000 – 700,000 particles • 3 – 5 millicuries • Given: • MAA Vial contains 6 x 106 particles (6 million) • Time = 12:00 (T=0) • Add 1.3 ml99mTc (30 mCi ) to vial • Add 3.7 ml of saline =30 mCi/5.0 ml =6 mCi/ml • Inject 0.7 ml = 4 mCi = 840,000 particles! 6,000,000/5ml = x/0.7ml X = 840,000 • Inject 0.5 ml = 3 mCi = 600,000 particles 6,000,000/5ml = x/0.5ml X = 600,000 Frank P. Dawry Physx.home.comcast.net Frank P. Dawry

  6. Particle number determinationmore dilute • Have: • 30 mCi 99mTc in 1.3 ml • Calibration time = 12:00 • Wanted Dose: • 200, 000 – 700,000 particles • 3 – 5 millicuries • Given: • MAA Vial contains 6 x 106 particles (6 million) • Time = 12:00 (T=0) • Add 1.3 ml99mTc (30 mCi ) to vial • Add 5.7 ml of saline =30 mCi/7.0 ml =4.3 mCi/ml • Inject 0.9 ml = 3.9 mCi = 1,080,000 particles!! 6,000,000/7ml = x/0.9ml X = 1,080,000 more dilute = more particles injected Frank P. Dawry Physx.home.comcast.net Frank P. Dawry

  7. Particle number determination more concentrated • Have: • 30 mCi 99mTc in 1.3 ml • Calibration time = 12:00 • Wanted Dose: • 200, 000 – 700,000 particles • 3 – 5 millicuries • Given: • MAA Vial contains 6 x 106 particles (6 million) • Time = 12:00 (T=0) • Add 1.3 ml99mTc (30 mCi ) to vial • Add 2.7 ml of saline =30 mCi/4.0 ml =7.5 mCi/ml • Inject 0.5 ml = 3.75 mCi = 400,000 particles☺ 6,000,000/7.5ml = x/0.5ml X = 400,000 more concentrated = less particles injected Frank P. Dawry Physx.home.comcast.net Frank P. Dawry

  8. Particle number determination High specific activity • Have: • 30 mCi 99mTc in 1.3 ml • Calibration time = 12:00 • Wanted Dose: • 200, 000 – 700,000 particles • 3 – 5 millicuries • Given: • MAA Vial contains 6 x 106 particles (6 million) • Time = 06:00 (T= 6 hours early) • Add 1.3 ml99mTc (60 mCi ) to vial • Add 3.7 ml of saline =60 mCi/5.0 ml =12 mCi/ml • Inject 0.3 ml = 3.6 mCi = 360,000 particles ☺ 6,000,000/5ml = x/0.3ml X = 360,000 more concentrated = less particles injected Frank P. Dawry Physx.home.comcast.net Frank P. Dawry

  9. Particle number determination Low specific activity • Have: • 30 mCi 99mTc in 1.3 ml • Calibration time = 12:00 • Wanted Dose: • 200, 000 – 700,000 particles • 3 – 5 millicuries • Given: • MAA Vial contains 6 x 106 particles (6 million) • Time = 18:00 (T= 6 hours later) • Add 1.3 ml99mTc (15 mCi ) to vial • Add 3.7 ml of saline =15 mCi/5.0 ml =3 mCi/ml • Inject 1.3 ml = 3.9 mCi = 1,560,000 particles !! 6,000,000/5ml = x/1.3ml X = 1,560,000 more dilute = more particles injected Frank P. Dawry Physx.home.comcast.net Frank P. Dawry

  10. Particle number determination Rule of ThumbNever draw greater than 1.0 ml into injection syringe. Prepare a fresh vial of MAA instead. Consider reconstituting vial with 5.0 ml saline and discarding 2.5 ml, then add the low specific activity 99mTc Calculations now based upon 3,000,000 particles in the vial of MAA Frank P. Dawry Physx.home.comcast.net Frank P. Dawry

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