Dose-Rate Dependence of Early Radiation Effects In Small Mammals

Bateman, J. L.; Bond, V.P.; Robertson, James S.

doi:10.1148/79.6.1008

Cited by 43 publications

(5 citation statements)

References 8 publications

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“…the amount is seen to vary for tumour and normal tissue and it is inconstant for individual frac tion schedules. Bateman et al [1] reported the data of dose rate effect of X-rays, supporting our results and the previous data by Chaplin et al [3].…”

Section: Discussionsupporting

confidence: 92%

The Response of Mouse Tumours to Fractionated Doses of Pions: Determination of Therapeutic Gain Factor

Ogawa

Goodman²,

Chaplin³

et al. 1991

Oncology

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Using the same experimental system which had been used to determine the pion relative biological effectiveness (RBE) for skin of mouse foot by Chaplin et al., we have determined the pion RBE for KHT sarcoma and SCCVII tumour transplanted in the foot of C3H mice. The pion RBE obtained by the tumour growth delay time method in comparison with 250 kVp X-rays at a dose rate of 150 cGy per min was determined to be 1.20,1.28 and 1.50 with single, 4 and’10 fractions, respectively, for KHT sarcoma. As for SCCVII tumour, it was determined to be 1.17, 1.45 and 2.05 with single, 4 and 10 fractions respectively. Therefore, it has been concluded that pions have various values of RBE depending on the tumour system involved. KHT sarcoma is a tumour which grows very rapidly, on the contrary, SCCVII tumour shows somewhat slower growth characteristics. These differences of RBE between these two tumour systems possibly stem from differences in the amount of hypoxic cells and/or their rates of reoxygenation. As for therapeutic gain factor, a maximum value of 1.45 was obtained with 10 fractions using the SCCVII tumour. Pions seem to be most effective (in multiple fractions) against tumours of relatively slow growth.

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Section: Discussionsupporting

confidence: 92%

The Response of Mouse Tumours to Fractionated Doses of Pions: Determination of Therapeutic Gain Factor

Ogawa

Goodman²,

Chaplin³

et al. 1991

Oncology

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“…The disappointing clinical results achieved with conventional radiation ther apy upon AVMs are in marked contrast to the success of single-fraction high-dose radiosurgical methods achieved with the linear accelerator [4], cobalt-60 unit [3], or synchrocyclotron [5], Although the absorbed radiation dose primarily deter mines the radiation response of biological tissues, radiation effectiveness also var ies with the cube root of the dose rate [9]. This dependence on dose rate implies a potential for recovery of biological tissues in the target volume.…”

Section: Discussionmentioning

confidence: 99%

Neuropathology of Intracranial Arteriovenous Malformations following Conventional Radiation Therapy

Elisevich

Redekop

Muñoz

et al. 1994

Stereotact Funct Neurosurg

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Conventional fractionated radiation therapy was used in 15 patients to treat arteriovenous malformations (AVMs) of the brain deemed inoperable or incompletely obliterated using endovascular or surgical techniques. The AVMs measured from 0.8 to 85 cm³ (mean 28.2 cm³; median 24 cm³). Angiography in 12 patients 1–21 years following radiation therapy demonstrated no significant change in 7, slight reduction in 2, near complete obliteration in 1, and complete obliteration in 2. Magnetic resonance imaging further demonstrated apparent obliteration in one other case. Three irradiated AVMs were available for pathological examination following fatal recurrent hemorrhage after 21 years in case 1 and following surgery after 5 years in cases 2 and 3. Doses of 20 and 45 Gy were delivered to the area of the AVM in 10 and 15 fractions with a 6-MV linear accelerator in case 1 and in cases 2 and 3, respectively. A blinded histopathological comparison was made of the latter cases and three AVMs removed at surgery that were not previously irradiated and that were comparable in size, number of arterial feeders, and location within the brain. Segmental hyalinization of some blood vessels was seen in both irradiated and nonirradiated cases. The single postmortem specimen showed extensive thrombosis but a patent nidus. The findings are in keeping with the clinical impression that conventional fractionated radiation therapy fails to alter the natural history of cerebral AVMs. The favorable outcome of radiosurgery on small- to medium-sized AVMs appears attributable to the shorter duration of therapy using relatively high-dose prescriptions to the nidus.

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“…The subscript 1 on the parameter θ was used to emphasize that the parameter represents the expected increase in the D 50 above its asymptotic value θ ∞ when y had unit value (e.g., y = 1 Gy/h). Based on the work of Bateman et al (1962), it was expected that n would be found to be approximately 1/3 (i.e., a y -1/3 dependence). However, central estimates considerably different from n = 1/3 were found in all cases where animal data spanned the dose rate range from about 10 -2 to 10 -1 Gy/h (Scott et al 1988).…”

Section: Functional Relationship Between D 50 and The Radiation Absormentioning

confidence: 99%

“…It is useful to review the development of Equation 3. Early research on the influence of radiation dose rate on D 50 ( y ) for death via the hematopoietic mode suggested that D 50 ( y ) decreased as a power function of y (e.g., θ y − n ), where θ and n are fixed positive parameters and y is a fixed value for the dose rate (see for example Bateman et al 1962). According to the indicated power function relationship, D 50 ( y ) progressively decreases towards zero as the dose rate y increases (Jones 1981; Morris and Jones 1988).…”

Section: Lethality Risk Avoidance Modelingmentioning

confidence: 99%

Calculating Hematopoietic-Mode-Lethality Risk Avoidance Associated with Radionuclide Decorporation Countermeasures Related to a Radiological Terrorism Incident

Scott¹

2009

Dose-Response

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This paper provides theoretical health-risk-assessment tools that are designed to facilitate planning for and managing radiological terrorism incidents that involve ingestion exposure to bone-seeking radionuclides (e.g., radiostrontium nuclides). The focus is on evaluating lethality risk avoidance (RAV; i.e., the decrease in risk) that is associated with radionuclide decorporation countermeasures employed to remove ingested bone-seeking beta and/or gamma-emitting radionuclides from the body. To illustrate the application of tools presented, hypothetical radiostrontium decorporation scenarios were considered that involved evaluating the hematopoietic-mode-lethality RAV. For evaluating the efficacy of specific decorporation countermeasures, the lethality risk avoidance proportion (RAP; which is the RAV divided by the total lethality risk in the absence of protective countermeasures) is introduced. The lethality RAP is expected to be a useful tool for designing optimal radionuclide decorporation schemes and for identifying green, yellow and red dose-rate zones. For the green zone, essentially all of the lethality risk is expected to be avoided (RAP = 1) as a consequence of the radionuclide decorporation scheme used. For the yellow zone, some but not all of the lethality risk is expected to be avoided. For the red zone, none of the lethality risk (which equals 1) is expected to be avoided.

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Dose-Rate Dependence of Early Radiation Effects In Small Mammals

Cited by 43 publications

References 8 publications

The Response of Mouse Tumours to Fractionated Doses of Pions: Determination of Therapeutic Gain Factor

The Response of Mouse Tumours to Fractionated Doses of Pions: Determination of Therapeutic Gain Factor

Neuropathology of Intracranial Arteriovenous Malformations following Conventional Radiation Therapy

Calculating Hematopoietic-Mode-Lethality Risk Avoidance Associated with Radionuclide Decorporation Countermeasures Related to a Radiological Terrorism Incident

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