Advertisement

Optimised tracer-dependent dosage cards to obtain weight-independent effective doses

  • F. JacobsEmail author
  • H. Thierens
  • A. Piepsz
  • K. Bacher
  • C. Van de Wiele
  • H. Ham
  • R.A. Dierckx
Original Article

Abstract

Purpose

The aim of this study was twofold: firstly, to determine whether the European Association of Nuclear Medicine (EANM) dosage card results in weight-independent effective doses or weight-independent count rates; secondly, to determine whether one dosage card is sufficient for 95 different radiopharmaceuticals, and, if not, how many cards we reasonably need to take into account inter-tracer variability.

Methods

Normalisation factors for count rate and effective dose were calculated as a function of body weight, with 70 kg as standard. Calculations were performed, using whole-body absorption fractions and MIRDOSE 3 software, for seven anthropomorphic phantoms and ten radionuclides. An analytic function for both relations was proposed. Normalisation factors for effective dose for 95 radiopharmaceuticals were investigated using cluster analysis.

Results

Normalisation factors for count rate and effective dose can be estimated accurately as a function of body weight W by (W/70) a holding only one parameter, called the a value. The a values for 95 radiopharmaceuticals were classified into three clusters (nA = 7, nB = 76, nC = 12). Cluster A contains tracers for renal studies. Cluster B contains all remaining tracers, except iodine-labelled tracers for thyroid studies and 89Sr for therapy, which belong to cluster C.

Conclusion

Correction factors proposed by the EANM task group mainly correct for effective dose. They are very similar to the factors obtained for cluster A. Using the EANM factors for tracers belonging to clusters B and C results in significantly higher effective doses to children. We suggest using three tracer-dependent dosage cards for which the correction factors have been calculated to obtain weight-independent effective doses.

Keywords

Effective dose MIRDOSE Dosage card Count rate Radiation risk 

References

  1. 1.
    Piepsz A, Hahn K, Roca I, Ciofetta G, Toth G, Gordon I, et al. A radiopharmaceutical schedule for imaging in paediatrics. Eur J Nucl Med 1990;17:127–9.PubMedGoogle Scholar
  2. 2.
    Cristy M, Eckerman K. Specific absorbed fractions of energy at various ages from internal photon sources. Cristy and Eckerman phantom series. ORNL/TM-8381 V1–V7. Oak Ridge, TN: Oak Ridge National Laboratory; 1987.Google Scholar
  3. 3.
    Annals of the ICRP. ICRP Publication 38. Radionuclide transformations, energy and intensity of emissions, vols 11–13. New York: Pergamon; 1983.Google Scholar
  4. 4.
    Stabin MG. MIRDOSE: personal computer software for internal dose assessment in nuclear medicine. J Nucl Med 1996;37:538–46.PubMedGoogle Scholar
  5. 5.
    Annals of the ICRP. ICRP Publication 53. Radiation dose to patients from radiopharmaceuticals, vol 18, Nos. 1–4. New York: Pergamon; 1987.Google Scholar
  6. 6.
    Annals of the ICRP. ICRP Publication 80. Radiation dose to patients from radiopharmaceuticals, vol 28, No. 3. New York: Pergamon; 1998.Google Scholar
  7. 7.
    Annals of the ICRP. ICRP Publication 60. Recommendations of the International Commission on Radiological Protection, vol 21, Nos. 1–3. New York: Pergamom; 1990.Google Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • F. Jacobs
    • 1
    Email author
  • H. Thierens
    • 2
  • A. Piepsz
    • 3
  • K. Bacher
    • 2
  • C. Van de Wiele
    • 1
  • H. Ham
    • 1
  • R.A. Dierckx
    • 1
  1. 1.Department of Nuclear MedicineGhent University HospitalGentBelgium
  2. 2.Department of Medical PhysicsGhent UniversityGentBelgium
  3. 3.CHU St Pierre, Department of Nuclear MedicineBrusselsBelgium

Personalised recommendations