Development of a shielded 241Am applicator for continuous low dose rate irradiation of rat rectum

Ravinder Nath, Sara Rockwell, Christopher R. King, Paul Bongiorni, Marianne Kelley, Darryl Carter

Research output: Contribution to journalArticlepeer-review


This paper describes the development of sources, applicators, and techniques that can be used to irradiate rat rectums with continuous irradiation at dose rates of interest in brachytherapy, either with the full circumference of the rectum irradiated, or with half of the circumference shielded from the radiation. The system uses encapsulated 241Am sources, to irradiate rat rectum with 60 keV photons continuously at a dose rate of up to 50 cGy/hr. Details of the design and fabrication of the 241Am sources, the rectal applicator, the dosimetry of the system, and the protocols for preparing and irradiating the rats, and for detecting early rectal injury using histological examination of irradiated rectum are presented. Highly effective shielding (attenuation factors as low as 0.04) of half of the circumference of the rat rectum was achievable. Unidirectional 241Am irradiators for intracavitary brachytherapy offer a unique tool for examining the effects of shielding a portion of the circumference of the rat radiation tolerance of the rectum.

Original languageEnglish (US)
Pages (from-to)175-181
Number of pages7
JournalInternational Journal of Radiation Oncology, Biology, Physics
Issue number1
StatePublished - 1992
Externally publishedYes


  • Am
  • Brachytherapy
  • Dose-volume effects
  • Rat rectum
  • Rectal injury
  • Shielding

ASJC Scopus subject areas

  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Radiation


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