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Biomedical subjects

T L Phillips

Publications and source records attributed to T L Phillips.

At least 199 records · Page 11Linked to original sources
PubMed1980

Radiotherapy with heavy charged particles at Lawrence Berkeley Laboratory.

Since July 1975, 157 patients have been irradiated with heavy charged particles at the Lawrence Berkeley Laboratory in a Phase I-II clinical trial to study the usefulness of these particles in the irradiation of human cancers. The particles utilized have included helium, primarily of interest because of improved dose distributions with reduction of dose to adjacent normal tissues, and heavier particles such as carbon, neon and argon ions which have the additional potential of increased biologic effectiveness against the tumor, especially hypoxic tumor cells. Initial results with helium particles have been sufficiently good to warrant a Phase III randomized trial in carcinoma of the pancreas; in other tumor sites, and with other particles, Phase I -- Phase II studies are in progress. Although follow-up is short, control within the irradiated area in this heterogeneous group of patients appears at least as good as with current megavoltage irradiation and complications to date are acceptably low, warranting further studies with heavy charged particles.

Argon↗
PubMed1980

Hyperthermia in cancer therapy.

Many malignant cell lines exhibit a therapeutic response to supernormal temperatures. Selective destruction of tumor cells has been observed following moderate hyperthermia (42 degrees to 43 degrees C) in vivo, and tumor eradication by heat has been achieved without normal tissue morbidity. Thermal cell killing appears to be independent of oxygen tension, and the sensitivity of S-phase cells to thermal damage is complementary to that for cellular radiation response. Hyperthermia is therefore a promising adjunct to radiotherapy. At the Claire Zellerbach Saroni Tumor Institute, Mount Zion Hospital and Medical Center, San Francisco, the differential thermal sensitivity of malignant cells is being studied to achieve improved tumor control in patients refractory to more conventional treatments. Preliminary results of a two-year clinical trial indicated increased local objective responses when hyperthermia and radiation were used in combination.

Diathermy↗
PubMed1979

Relative biological effectiveness of low- and high-LET radiotherapy beams for jejunal crypt cell survival at low doses per fraction.

In order to determine the relative biological effectiveness (RBE) of various low- and high-LET radiotherapy beams of low coses, LAF1 mice were exposed to one dose and 10 equally fractionated doses of 60Co gamma rays, 137Cs gamma rays, 4-MeV x rays, 300-kVp x rays, helium ions in the plateau and Bragg-peak region, and 15-MeV neutrons; survival of jejunal crypt cells with the microcolony assay of Withers and Elkind was determined using 60Co as the standard. RBE values for the survival of 10 cells/circumference for 10 fractionated exposures (2.4 Gy [240 rad] per fraction of 60Co) were: 1.07 for 137Cs, 1.06 for 4-MeV x rays, 1.16 for 300-kVp x rays, 1.10 for helium ions in the plateau, 1.29 for helium ions in the peak, and 3.02 for 15-MeV neutrons. As LET increased, RBE increased with decrease of dose/fraction.

Animals↗
PubMed1979

Thermal dosimetry and clinical requirements.

Major problems in clinical hyperthermia include (a) inhomogeneity of heat distribution in designated tumor volumes due to tissue characteristics and differential blood flow, (b) limitations of heat delivery and control systems for adequate depth penetration and adjustments of temperatures, and (c) the lack of capability of accurate temperature measurements, especially in the area of noninvasive techniques for deep-seated tumors. Examples were given to illustrate the clinical requirements of hyperthermia of superficial, intermediate, and deep-seated tumors.

Brain Neoplasms↗
PubMed1979

Combined radiotherapy and multidrug chemotherapy for advanced head and neck cancer: results of a Radiation Therapy Oncology Group pilot study.

Between February 1976 and June 1977, 15 patients with advanced inoperable squamous cell carcinoma of the head and neck were entered in a pilot study sponsored by the Radiation Therapy Oncology Group using combined radiotherapy and multidrug chemotherapy. Chemotherapy consisted of cyclophosphamide, vincristine, and bleomycin (during radiotherapy) and cyclophosphamide, methotrexate, and bleomycin (after radiotherapy). At the time of last followup or of death, the disease had been controlled at the primary site in eight of the 15 patients (53%), in the neck in 12 patients (80%), and in all sites in seven patients (47%). Followup time ranged from 2 to 24+ months with a median of 7 months. Acute toxic effects of the combined treatment, primarily enhanced radiation mucositis and infection, were severe, and three patients had fatal complications. Although the combination chemotherapy may have enhanced the tumor response to radiotherapy in some of these patients, treatment morbidity and complications were prohibitive for the treatment program to progress to a randomized trial.

Adult↗