Late effects of radiation on the lumbar spinal cord of guinea pigs: Re-treatment tolerance

Journal Article · Thu Jul 15 00:00:00 EDT 1993 · International Journal of Radiation Oncology, Biology and Physics; (United States)

DOI:https://doi.org/10.1016/0360-3016(93)90282-Z· OSTI ID:6694866

Mason, K A ^[1]; Withers, H R; Chiang, Chi-Shiun ^[2]

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1. Univ. of Texas M.D. Anderson Cancer Center, Houston, TX (United States)
2. Univ. of California, Los Angeles, CA (United States)

Using a guinea pig model of lumbar myelopathy, various factors affecting the tolerance of spinal cord to irradiation were assessed: (a) extent of initial injury; (b) time interval between priming and test doses; and (c) animal age at the time of initial radiation treatment. A 3 cm section of lumbar spinal cord of guinea pigs was irradiated with fractionated doses of 4.5 Gy gamma rays given as 9 fractions per week. Guinea pigs were primed with 9 x 4.5 Gy in 7 days which is 60% of the ED[sub 50] for a continuous course of treatment. After 28 or 40 weeks, animal were retreated with 6-14 fractions of 4.5 Gy. Animals were observed for 2 years following the priming dose and both the incidence and latency of myelopathy recorded. Young adult guinea pigs (8 wk old) showed both a decreased radiation tolerance and latency compared to old individuals (40 wk old). At 28 or 40 wk after 9 x 4.5 Gy, only about 8% of the initial injury was remembered in young adult guinea pigs. The amount of residual injury was dependent on the initial damage as a proportion of the tolerance dose. The spinal cord shows a greater capacity for long-term recovery than generally appreciated and re-treatment doses clinically prescribed may be lower than necessary. 8 refs., 3 figs., 2 tabs.

• OSTI ID: 6694866
• Journal Information: International Journal of Radiation Oncology, Biology and Physics; (United States), Vol. 26:4; ISSN 0360-3016
• Country of Publication: United States
• Language: English

Related Subjects

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
RADIOTHERAPY
SIDE EFFECTS
SPINAL CORD
RADIATION INJURIES
FRACTIONATED IRRADIATION
BIOLOGICAL EFFECTS
BIOLOGICAL RADIATION EFFECTS
CENTRAL NERVOUS SYSTEM
INJURIES
IRRADIATION
MEDICINE
NERVOUS SYSTEM
NUCLEAR MEDICINE
RADIATION EFFECTS
RADIOLOGY
THERAPY
560152* - Radiation Effects on Animals- Animals