Mird237 2021 [updated] May 2026

To provide an accurate write-up, could you please clarify what mird237 2021 refers to?

Based on a preliminary search, this term does not appear to be a widely known public topic, standard technical code, or recent major event in major databases. It could potentially be:

A specialised internal code for a specific organization (e.g., a case number, internal report, or project ID). mird237 2021

A highly specific academic or medical identifier (such as a protein, gene, or study ID).

A model or part number for industrial or consumer equipment. To provide an accurate write-up, could you please

If you can provide a bit more context—such as the industry, organization, or field it belongs to—I can certainly put together a more detailed and informative summary for you.

2.1. Radiation Fundamentals

  • Types of radiation (alpha, beta, gamma, neutron)
  • Interaction mechanisms (photoelectric effect, Compton scattering, pair production)
  • Attenuation coefficients and half-value layer (HVL)

2. Updated Nuclear Decay Data

The 2021 revision uses ICRP 107 and NuDat 3.0 decay data. For common therapeutic radionuclides, this impacted: Types of radiation (alpha, beta, gamma, neutron) Interaction

  • Lu-177: Improved beta minus spectra branching ratios.
  • I-131: More accurate gamma and conversion electron yields.
  • Ac-225: Revised alpha emission probabilities (critical for targeted alpha therapy).

Part 1: The Legacy – What Was MIRD Before 2021?

To appreciate the 2021 revision, we must first understand its predecessor. The original MIRD schema (often referred to as MIRDOSE or OLINDA/PC) relied on radiation transport data from 1999 – primarily based on Cristy and Eckerman’s phantom work.

Key limitations of pre-2021 versions:

  • Outdated Anatomical Models: The stylized (geometric) phantoms of the 1970s-1990s did not accurately represent modern patient morphometry.
  • Fixed Organ Masses: They assumed “Reference Man” (70 kg, 170 cm) and “Reference Woman” (58 kg, 160 cm), ignoring obesity, cachexia, or pediatric variations.
  • Limited Particle Tracking: Older transport codes simplified electron and photon interactions in heterogeneous tissues.

The result was systematic errors in absorbed dose calculations—sometimes exceeding 30% for non-reference individuals.

Scroll to Top