James Shaeffer

Radiometric sensing: an adjuvant to mammography to determine breast biopsy

Radiometric sensing, ONCOSCAN, is a noninvasive test of thermal activity in the breasts which measures microwave emissions by passive microwave radiometry. Microwave radiometric sensing will be shown to be a promising technique which, when combined with mammography, could be useful in reducing non-cancerous breast biopsies based on mammographic false positives, thereby improving the positive predictive value (PPV) of mammography. PPV is defined as the number of malignancies per number of biopsies performed. At the time of this writing, more than 90 women scheduled for open breast biopsy based on abnormal mammographic findings underwent ONCOSCAN testing prior to biopsy. These abnormal mammographic findings basically non-palpable. Various algorithms have been devised, following knowledge of biopsy outcome which separated the ONCOSCANs into those with low or high thermal activity.

Radiation control of microscopic pulmonary met ast ases in C3H mice

C3HBA adenocarcinoma cells injected intravenously into isogeneic C3H/HeJ mice result in the formation of visible lung colonies which are introduced as a model for pulmonary metastases. Visible lung colonies are both time dependent and injected cell number dependent. Control of the lung colonies at their microscopic (subclinical) stage is achieved by a single radiation dose of 2100 rads, which is far less than the dose necessary to control palpable primary tumors. An in vivo survival curve for the microscopic lung colonies irradiated with graded single doses is resented.

Radioprotective Effect of Polyethylene Glycol

Polyethylene glycol of molecular weight 400 (PEG-400) had a radioprotective effect of about 20% against lethality when given ip 20 min prior to single or fractionated X-ray doses to the head and neck. Dose modification factors (DMF) based on LD50/15 values ranged from 1.14 to 1.24. A similar DMF of 1.12 based on LD50/30 values was obtained using single doses of whole-body X irradiation. Mice given head and neck irradiation had significantly reduced rectal temperatures (31.3 +/- 3.0 degrees C) 9 days post irradiation compared with unirradiated controls (35.4 +/- 0.6 degrees C). No such reduction was observed when PEG-400 was given with radiation (36.3 +/- 0.9 degrees C). PEG-400 also lessened, but not significantly, the frequency of shivering in irradiated animals. Histopathologic examination of the oral structures demonstrated only marginal protection by PEG-400. Estimation of the alpha/beta ratio from LD50 data on head and neck-irradiated mice yielded values of 4.4 +/- 1.9 (95% confidence limits) Gy without PEG-400 and 7.9 +/- 1.4 Gy with PEG-400. Since it is a non-thiol radioprotector, PEG-400 may be more useful when combined with more conventional thiol-containing radioprotectors.

Thermal Drift In Microwave Thermography

Thermal drift in microwave thermography results from prolonged contact between a microwave antenna at one temperature and a subject at a different temperature. Appropriate antenna heating can minimize thermal drift, permitting more accurate temperature measurements.

Lung Colony Assays of Murine Mammary Tumor Cells Irradiated In Vivo and In Vitro

C3HBA tumor cells were irradiated either in vitro prior to their intravenous injection or in vivo by whole lung irradiation 24 hours after their intravenous injection into isologous tumor-free C3H∕HeJ female mice. The animals were sacrificed 28 days following treatment, and the number of lung colonies in each treatment group was expressed as the percentage of lung colonies present in untreated (control) mice. Both in vivo and in vitro survival curves had similar values of D0, but had different extrapolation numbers which were 3.4 and 1.0, respectively. Possible underlying causes for the difference in survival curves are discussed.

Treatment of Metastatic Osteosarcoma by Cyclophosphamide and Radiotherapy

Osteosarcoma cells were injected intravenously into isologous C3H∕He mice to produce pulmonary colonies or “metastases.” Either cyclophosphamide in doses up to 150 mg∕kg × 3 or thoracic irradiation in doses up to 2,100 rads was given one day postinjection when pulmonary colonies were occult or 14 days postinjection when they were manifest. The number of colonies was scored in treated and sham-treated control animals 28 days postinjection.

Dual Mode Microwave System to Enhance Early Detection of Cancer

A dual-mode microwave system has been developed that will permit early detection of cancer. The system combines the use of the passive microwave radiometer [1]-[3] with an active transmitter. The active transmitter will provide localized heating to enhance early detection by taking advantage of the differential heating (i.e., tumor temperature with respect to surrounding tissue) associated with thermal characteristics of tumors.

The Effect of Antenna Match on Microwave Radiometric Thermal Patterns

Microwave thermographic profiles of the breast region of healthy female volunteers were obtained using a 4.7 GHz radiometer. Apparent temperature elevations of about 0.4°C were seen in the areolar (nipple) region compared to the other areas of the breast. At least half of this apparent areolar temperature elevation may be attributed to improved antenna match at that site. The importance of antenna match in the proper evaluation of microwave thermographic studies is emphasized.

Variation of the Relative Biologic Effectiveness with Tumor Size Using Accelerated Helium Ions

The RBE of an accelerated helium ion beam was determined on murine osteosarcomas ranging in size from single cells to visibly detectable lung colonies of approximately 1 X 10(-2) mm3. That the RBE increased as tumor size increased provides some biologic basis for the selection of advanced cases of neoplasia for clinical trials using relatively high LET radiation sources.

The effect of BUdR on the cycle of irradiated and unirradiated meristematic cells of Vicia faba

The cell cycle time of the meristematic cells of Vicia faba was approximately 20 hr in both the control cells and in the cells treated with TdR (1·6 × 10−5 m ) for 24 hr. Cells treated for 24 hr with an equimolar concentration of BUdR showed prolongation of their cell cycle time to about 24 hr. The main detectable change in the cell cycle was the lengthening of the S phase which was increased to 13 hr from 8 hr which was the value for the S phase of the control and TdR-treated cells. BUdR-treated cells exhibited more radiation-induced damage, measured as micronuclei, than control or TdR-treated cells. The radiosensitization effect was manifested as an increase in the percent of damaged cells but not as an increase in the damage per damaged cell. An attempt to correlate the BUdR-induced changes in the cell cycle with the BUdR-induced increase in radiation response was presented.