Photon activation therapy and brachytherapy

Brenda H. Laster, Dabney W. Dixon, Sara Novick, Jon P. Feldman, Veronique Seror, Zvi I. Goldbart, John A. Kalef-Ezra

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Purpose: In photon activation therapy (PAT), energy deposition at critical sites within a tumor can be increased by complexing the DNA with higher Z atoms, and provoking the emission of Auger electrons after inducing a photoelectric effect. This in vivo study evaluates the hypothesis using X-rays from palladium-103 seeds to excite the L-edge of platinum (Pt) atoms bound to the DNA of cancerous cells. Methods and Materials: Pt (II) tetrakis(N-methyl-4-pyridyl) porphyrin chloride was used to locate Pt atoms adjacent to the DNA of the KHJJ murine mammary carcinoma; a 2.3-mCi palladium-103 seed was implanted in the tumor. Results: The tumor periphery received subtherapeutic doses. The rate of tumor growth in mice treated with PAT was slower than in mice treated with brachytherapy only. Conclusions: The tumor growth delay for PAT-treated mice is attributed to Auger emission from Pt atoms that produced substantial local damage. However, other co-existing mechanisms cannot be ruled out.

Original languageEnglish
Pages (from-to)324-330
Number of pages7
Issue number3
StatePublished - 1 Jul 2009


  • Auger electrons
  • Brachytherapy
  • Cancer
  • L-absorption edge
  • Photoelectric absorption
  • Photoelectric effect
  • Platinum
  • Porphyrin
  • Radiation
  • TMPyP4

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging


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