Practical determination of patient-specific marrow dose using radioactivity concentration in blood and body

Sui Shen, Gerald L. DeNardo, George Sgouros, Robert T. O'Donnell, Sally J. DeNardo

Research output: Contribution to journalArticlepeer-review

61 Scopus citations


Accurate determination of red marrow radiation is important because myelotoxicity is often dose limiting in radioimmunotherapy. The S-value methodology assumes a fixed red marrow mass as defined by the standard Medical Internal Radiation Dose (MIRD) mathematic phantom. Substantial error can be introduced in marrow radiation estimates because red marrow mass varies from patient to patient. In this work we describe a patient-specific marrow dosimetry methodology that does not require an explicit estimate of marrow mass. Methods: Photon radiation to marrow from all sources can be considered as the total body to marrow. Based on photon radiation from body and electron radiation from blood, a patient-specific marrow dose can be determined by counting blood and total body radioactivity and measuring body weight. Results: The deviation in marrow dose calculation using total body to represent all photon radiation was 3.9% in 66 patients administered 131I- labeled antibodies and was 9.1% in 18 patients administered 67Cu-labeled antibodies. The differences between this patient-specific approach and estimates based on standard anatomy were considerable, ranging from -35% to 88%. The differences were greater when patients' weights differed substantially from the MIRD reference man phantom. Conclusion: For radiopharmaceuticals that do not bind marrow, patient-specific marrow dosimetry can be independent of the actual marrow mass of a patient. Patient- specific marrow dosimetry can be determined using radioactivity concentration in blood and body.

Original languageEnglish (US)
Pages (from-to)2102-2106
Number of pages5
JournalJournal of Nuclear Medicine
Issue number12
StatePublished - Dec 1999
Externally publishedYes


  • Marrow dosimetry
  • Radiation dosimetry
  • Radioimmunotherapy
  • Radionuclide therapy

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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