Design and characterization of an economical (192)Ir hemi-brain small animal irradiator.
OBJECTIVE
To describe the design and dosimetric characterization of a simple and economical small animal irradiator.


METHODS
A high dose rate (HDR) (192)Ir brachytherapy source from a commercially available afterloader was used with a 1.3 cm thick tungsten collimator to provide sharp beam penumbra suitable for hemi-brain irradiation of mice. The unit was equipped with continuous gas anesthesia to allow robust animal immobilization. Dosimetric characterization of the device was performed with Gafchromic film measurements.


RESULTS
The tungsten collimator provided a sharp penumbra suitable for hemi-brain irradiation, and dose rates on the order of 200 cGy/minute were achieved. The sharpness of the penumbra attainable with this device compares favorably to those measured experimentally for 6 MV photons, and 6 and 20 MeV electron beams from a linear accelerator, and was comparable to those measured for a 300 kVp orthovoltage beam and a Monte Carlo simulated 90 MeV proton beam.


CONCLUSIONS
Due to its simplicity and low cost, the apparatus described is an attractive alternative for small animal irradiation experiments requiring steep dose gradients.
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Michael P
MP
Grams
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Zachary C
ZC
Wilson
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Terence T
TT
Sio
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Chris J
CJ
Beltran
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Erik J
EJ
Tryggestad
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Shiv K
SK
Gupta
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Charles R
CR
Blackwell
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Kevin P
KP
McCollough
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Jann N
JN
Sarkaria
Department of Radiation Oncology , Mayo Clinic , Rochester , Minnesota , USA.
Keith M
KM
Furutani
D000818:Animals; D001918:Brachytherapy / Q000191:economics / Q000295:instrumentation* / Q000662:veterinary*; D001921:Brain / Q000528:radiation effects*; D017076:Computer-Aided Design; D003362:Cost-Benefit Analysis; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007496:Iridium Radioisotopes / Q000191:economics / Q000494:pharmacology*; D051379:Mice; D008904:Miniaturization; D011829:Radiation Dosage; D011874:Radiometry / Q000191:economics / Q000295:instrumentation / Q000662:veterinary; D014916:Whole-Body Irradiation / Q000191:economics / Q000295:instrumentation* / Q000662:veterinary*
D007496:Iridium Radioisotopes
Iridium-192 HDR; Small animal irradiator; hemi-brain