Effect of Negative Pions on the Proliferative Capacity of Ascites Tumor Cells (Lymphoma) in Vivo

Inactivation of Human Kidney Cells by High-Energy Monoenergetic Heavy-Ion Beams

“…It is also likely that some aneuploid and hyperploid tumor cells are more sensitive to high-LET particle damage than are normal diploid cells (27,28). Some preliminary studies show that high-LET particles decrease the radioresistance of cells in spheroid culture compated to single-cell systems, a factor that might be due to altered environmental conditions or communication (29) between cells of the spheroid.…”

The RBE of Negative Pions in 2-Day-Old Ascites Tumors

“…Cell survival curve results have been summarized in Table II along with the results obtained in our previous report (1). Figure 3 shows the survival curve following irradiation with i-at the Bragg peak for the 2-day-old tumor.…”

Radiobiological Considerations for Pions in Radiotherapy

“…All the mice were injected with 106 L-2 lymphoma cells 3 and 5 days prior to the beginning of the irradiation. Animals bearing 3-day-old tumors at the beginning of the experiment were used for cytological studies [23,45,46], and the mice starting irradiation with 5-day-old tumors were used to test tumor-forming ability [24]. Control experiments under identical conditions were carried out using " Co y-rays and were done at a comparable dose rate as a low LET control.…”

“…Information on the survival of a well-oxygenated tumor compared to the hypoxic tumor was obtained using a 2-day-old lymphoma (oxygenated) ascites tumor and compared to a 5-day-old (hypoxic) ascites tumor [24,26], D ose, rad …”

“…With still larger particles, RBE begins to fall although the OER remains about 1.0. Interest in pions arises from the high peak-to-plateau ratio of their Bragg peak, the broadness of the peak, RBE factors of about 3 to 5 [23,24,26,46,59,70], the reduction of the oxygen effect [60], and the ability to produce by scanning techniques, sharply defined therapeutic volumes of large size, e.g., 10 x 10 x 10 cm [59,73],…”