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Charles B. Wilson and Takao Hoshino

) gave cell-generation times in the range of 24 hours for glioblastomas in cell culture. At present we are attempting to determine the duration of the “S” phase in glioblastomas by using a double label in vivo and in vitro. Tumor-Doubling Time The period in which a tumor doubles its volume is referred to as the “tumor-doubling time.” 8 The number of cells in a tumor is the most fundamental measure of tumor size, and tumor volume is proportional to the number of tumor cells only if the mean effective volume per cell remains constant during growth. For the

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Ruth G. Ramsey and William N. Brand

1965 we began a clinical study of limited field versus whole brain irradiation of selected patients who had positive angiograms, a lesion well defined on the brain scan, and histological confirmation with craniotomy and gross total removal when possible. All these patients were given corticosteroids postoperatively. Several authors have shown the reliability of brain scans in the diagnosis, localization, and delineation of brain tumors, 6 and we therefore felt confident that the entire tumor volume would be included in the limited treatment port. Any treatment

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tumor volume. In regard to patients selected for limited volume irradiation, we must also agree with Dr. Walker that it is impossible to separate the influence of the patients selected from any response to the dose of irradiations given in explaining the final results. As mentioned in our paper, the location of the tumor plays a role in prognosis. If future studies are able to demonstrate a dose response curve for glioblastoma multiforme, then this factor of location coupled with the ability to restrict irradiation to the diagnostically defined limits of the tumor

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Takao Hoshino and Charles B. Wilson

; rapid regrowth indicates that they possess a higher growth fraction and that nonproliferating cells have the capacity rapidly to enter the proliferating pool. Growth in malignant gliomas appears to be depressed by crowding, and partial removal of the tumor stimulates cells in the nonproliferating pool to move into the proliferating pool, rapidly repopulating the tumor. Thus, removal does not significantly reduce the proliferating population, and only temporarily reduces tumor volume. Solid tumors such as glioblastomas respond poorly to cycle-specific or phase

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Takao Hoshino, Charles B. Wilson, Mark L. Rosenblum and Marvin Barker

different, the ratio can be estimated using the viable tumor volume (Vv), nonviable tumor volume (Vnv), and relative cell densities (Dv and Dnv) according to the following formula: For example, if 50% of all tumor cells were located in “nonviable” areas, the total tumor growth fraction would be 0.15 instead of the calculated 0.30. Application of Model in Planning Treatment The selection of anti-cancer drugs for use in patients with glioblastomas should utilize information on the agent's mechanism of action in relation to tumor cell kinetics as well as its

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evoked spinal electrogram Yasuhiko Matsukado Mamoru Yoshida Tomokazu Goya Koki Shimoji April 1976 44 4 435 441 10.3171/jns.1976.44.4.0435 Glioblastoma multiforme in children George J. Dohrmann Jacqueline R. Farwell John T. Flannery April 1976 44 4 442 448 10.3171/jns.1976.44.4.0442 Tumor volume, luxury perfusion, and regional blood volume changes in man visualized by subtraction computerized tomography Richard D. Penn Randal Walser Diane Kurtz Laurens Ackerman April 1976 44 4 449 457 10.3171/jns.1976.44.4.0449 Computer mapping of brain-stem sensory

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Richard D. Penn, Randal Walser, Diane Kurtz and Laurens Ackerman

vascularized neoplastic tissue may be important in explaining failure of chemotherapeutic agents and radiotherapy. Subtraction scans should allow serial assessment of changes in overall tumor volume as well as inner core size and, hopefully, guide therapeutic intervention. Case 2 demonstrates how the subtraction technique can delineate regions of infarction by decreased relative blood volume. Also shown is an area of increased blood volume around the infarction that could be due to luxury perfusion. Until now only regional cerebral blood flow studies have been used to

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Bryce Weir, Pierre Band, Raul Urtasun, Gilles Blain, Don McLean, Fred Wilson, Bruce Mielke and Michael Grace

patients had high-grade astrocytomas, but that the needle biopsy had missed the representative portion of the tumor. Treatment Groups All 41 patients, 30 males and 11 females, were randomly allocated within 2 weeks of surgery to one of three treatment groups. In Group 1, total radiation dosages of 4000 to 4500 rads were administered in 25 treatments in an overall time of 5 weeks to a tumor volume of 13 × 10 cm to 14 × 11 cm, encompassing at least two-thirds of the brain, using lateral opposing fields with the cobalt-60 megavoltage unit as the source. In Group 2

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Brain-tumor therapy

Quantitative analysis using a model system

Mark L. Rosenblum, Kathy D. Knebel, Dolores A. Vasquez and Charles B. Wilson

tumor volume doubling time of 40 hours was determined for tumors of 3 to 100 mg, 8 to 15 days after transplantation. Marked variation in tumor growth was observed ( Fig. 2 ). Fig. 2. Graph shows analysis of untreated tumor growth in vivo . Each point represents the mean weight for six tumors obtained from animals sacrificed at various intervals after transplantation. The error bars represent the 95% confidence intervals. BCNU Treatment Least squares regression analysis of the surviving fraction of cells from tumors treated with up to 0.75 × LD 10

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Richard D. Penn and Diane Kurtz

–123, 1974 8. Penn RD , Walser R , Ackerman L : Cerebral blood volume in man: computer analysis of a computerized brain scan. JAMA 234 : 1154 – 1155 , 1975 Penn RD, Walser R, Ackerman L: Cerebral blood volume in man: computer analysis of a computerized brain scan. JAMA 234: 1154–1155, 1975 9. Penn RD , Walser R , Kurtz D , et al : Tumor volume, luxury perfusion, and regional blood volume changes in man visualized by subtraction computerized tomography. J Neurosurg 44 : 449 – 457