LII:Radiation Oncology/Physics/AAPM

American Association of Physicists in Medicine (AAPM)

AAPM Reports

Task Groups:

TG 34 (PDF) - "Management of Radiation Oncology Patients with Implanted Cardiac Pacemakers" (Reprinted from Medical Physics, Vol. 21, Issue 1) (1994)
TG 36 (PDF) - Fetal Dose from Radiotherapy with Photon Beams
TG 40 (PDF) - Comprehensive QA for Radiation Oncology
TG 43 (PDF) - Dosimetry of Interstitial Brachytherapy Sources (1995)
- Update of formalism and source characterizations (PDF)
- Impact of implementation on prostate doses (PDF)
TG 60 - Intravascular Brachytherapy Physics
TG 63 (PDF) - Dosimetric considerations for patients with HIP prostheses undergoing pelvic irradiation
TG 65 (AAPM 85) - Tissue Inhomogeneity Corrections (PDF, 2004)

TG 43 (Dosimetry of Interstitial Brachytherapy Sources)

Introduction: New formalism needed due to significant variance in exposure rate constants, and due to difficulty of accurately calculating 2D dose distribution in tissue due to significant anisotropy of actual cylindrical brachytherapy sources
Description of sources: Iridium-192, Iodine-125, Palladium-103
Recommended dose calculation formalism:
- Historically: Dose rate = A * f * Γ * 1/r² * T(r) * Φ
- New: Dose rate = S_k * Λ * G(r,θ)/G(r0,θ0) * g(r) * F(r,θ)
  - S_k: air kerma strength, usually specified at 1 m, unit defined by U (μGy m² h^-1
  - Λ: dose rate constant, defined as dose rate to water at a distance 1 cm on the transverse axis
  - G(r,θ): geometry factor, accounts for variation of relative dose due only to spatial distribution of activity within the source, ignoring photon absorption and scattering
  - g(r): radial dose function, accounts for effects of absorption and scatter in the medium along the transverse axis of the source
  - F(r,θ): anisotropy function, accounts for anisotropy of dose distribution around the source, including the effects of absorption and scatter in the medium
  - Reference point (r0, θ0): lies on transverse bisector of the source, at a distance of 1 cm from its center
- Recommended dosimetry parameters provided for I-125, Ir-192, and Pd-103