title: Single dose irradiation of defined region of rat brain with stereotactic brainlab system.
abstract: Background and purpose of our study was to develop a precise dose delivery technique for partial brain irradiation of two rats simultaneously.
  
  
  METHODS
  Using a self-developed frame stereotactic radiotherapy with single doses of 30-90 Gy was delivered to the frontal lobe of 22 animals. Tolerability and reproducibility of the method were evaluated and dosimetric measurements were conducted to verify the treatment plans. 2, 4 and 6 months after the irradiation magnetic resonance imaging (MRI) scans and histopathological examinations were performed to detect late radiation induced biological changes.
  
  
  RESULTS
  Immobilization device provided excellent reproducibility and tolerability. Dosimetry revealed good correspondence with planned dose distribution, but the measured absorbed dose was 30% lower than the planned dose. During the 6 months follow-up period the procedure related death of subject animals after 30 Gy, 70 Gy and 90 Gy were 0%, 20% and 100% respectively. T2 signal and structural changes on MRI scans found to be dose and time dependent. While 30 Gy caused no detectable structural changes, 70 Gy lead to cystic necrosis in 2 cases after 4 month. Histopathology revealed signs of necrosis on macroscopic examination after 70 Gy in the high dose region involving both frontal lobes, and no obvious microscopic changes in the surrounding area were detectable.
  
  
  CONCLUSIONS
  Our technique of rat cranial irradiation using human stereotactic system provided high accuracy of single dose delivery for a pair of small animals, resulting in brain injury in the defined area. This method proved to be a reproducible model for preclinical studies on radiation effects.
authors.forename: Róbert
authors.initials: R
authors.lastname: Farkas
authors.forename: Judit
authors.initials: J
authors.lastname: Kalincsák
authors.forename: Péter
authors.initials: P
authors.lastname: Kovács
authors.forename: Mihály
authors.initials: M
authors.lastname: Aradi
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Bellyei
authors.forename: Roland
authors.initials: R
authors.lastname: Weiczner
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Sebestyén
authors.forename: Imola
authors.initials: I
authors.lastname: Plangár
authors.forename: Katalin
authors.initials: K
authors.lastname: Hideghéty
mesh_terms: D000818:Animals; D001921:Brain / Q000528:radiation effects*; D016371:Cranial Irradiation / Q000379:methods*; D005260:Female; D021621:Imaging, Three-Dimensional; D007103:Immobilization; D008279:Magnetic Resonance Imaging; D016634:Radiosurgery / Q000379:methods*; D011879:Radiotherapy Dosage; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results