TY - JOUR
T1 - Bath and Shower Effect in Spinal Cord
T2 - The Effect of Time Interval
AU - Philippens, Marielle E.P.
AU - Pop, Lucas A.M.
AU - Visser, Andries G.
AU - Peeters, Wenny J.M.
AU - van der Kogel, Albert J.
N1 - Funding Information:
This work was supported by a grant from the Dutch Cancer Society (KUN99-2080).
PY - 2009/2/1
Y1 - 2009/2/1
N2 - Purpose: To evaluate the time dependency of the sensitizing effect of a large low-dose field on a small high-dose field in the rat cervical spinal cord. Methods and materials: Irradiation experiments with a relatively low dose to a large volume (bath, 2 cm, 4 Gy) were combined with high doses to a small volume (shower, 4.7 mm, 26-43 Gy) at intervals of 8 minutes and 3, 12, and 24 hours. Both a functional score defined as motor impairment and a histologic score characterized as white matter necrosis were used as end points. Results: Application of the 4-Gy bath dose resulted in a significant decrease in 50% isoeffective dose (ED50) from 48.7 Gy (small field) to 40.8 Gy. If the interval was extended, the ED50 increased to 44.4 (3 hours) and 44.8 Gy (12 hours), whereas a 24-hour interval resulted in a significant increase to 51.9 Gy. If the histologic end point was considered, the ED50 for all dose-response curves decreased slightly with 0.2 to 2.6 Gy without significantly changing the kinetics. Conclusions: The bath effect as applied in the bath-and-shower experiment lasted for at least 12 hours and disappeared in the 24-hour interval. This time scale clearly deviates from the repair kinetics in spinal cord derived from low-dose-rate and fractionated irradiations.
AB - Purpose: To evaluate the time dependency of the sensitizing effect of a large low-dose field on a small high-dose field in the rat cervical spinal cord. Methods and materials: Irradiation experiments with a relatively low dose to a large volume (bath, 2 cm, 4 Gy) were combined with high doses to a small volume (shower, 4.7 mm, 26-43 Gy) at intervals of 8 minutes and 3, 12, and 24 hours. Both a functional score defined as motor impairment and a histologic score characterized as white matter necrosis were used as end points. Results: Application of the 4-Gy bath dose resulted in a significant decrease in 50% isoeffective dose (ED50) from 48.7 Gy (small field) to 40.8 Gy. If the interval was extended, the ED50 increased to 44.4 (3 hours) and 44.8 Gy (12 hours), whereas a 24-hour interval resulted in a significant increase to 51.9 Gy. If the histologic end point was considered, the ED50 for all dose-response curves decreased slightly with 0.2 to 2.6 Gy without significantly changing the kinetics. Conclusions: The bath effect as applied in the bath-and-shower experiment lasted for at least 12 hours and disappeared in the 24-hour interval. This time scale clearly deviates from the repair kinetics in spinal cord derived from low-dose-rate and fractionated irradiations.
KW - Dose-volume effects
KW - Nonuniform dose distribution
KW - Repair
KW - Spinal cord
KW - White matter necrosis
UR - http://www.scopus.com/inward/record.url?scp=58149336856&partnerID=8YFLogxK
U2 - 10.1016/j.ijrobp.2008.09.028
DO - 10.1016/j.ijrobp.2008.09.028
M3 - Article
C2 - 19046823
AN - SCOPUS:58149336856
SN - 0360-3016
VL - 73
SP - 514
EP - 522
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 2
ER -