Yosh Maruyama

Radiotherapy of Tympanojugular Ohemodectomas1

The characteristic features and radiotherapy of chemodectomas of the tympanojugular region as seen in 16 cases are reported with respect to (a) survival, (b) regression of external ear manifestations, (c) vascular response, and (d) hormone response. Radiation treatment is effective in producing local tumor control; however, for a pheochromocytoma, irradiation should be combined with surgical removal of as much functional tumor as possible. Selective embolization may be effective in obliterating the tumor vessels following radiotherapy and thus arresting tumor progression.

Contribution of Host Resistance to Radiosensitivity of an Isologous Murine Lymphoma in Vivo

SummaryLSA ascites lymphoma cells were irradiated in vitro and assayed in vivo in isologous recipients. Results with the TD50 method were correlated with a separate assay using an inoculum containing a fixed total number of tumour cells and measuring the 50 per cent sterilization dose (SD50) of x-radiation. Comparison of sham- and pre-irradiated recipients showed differences which were consistent with the presence of isoantigenic tumour antigens, using the SD50 method. Host-resistance against the tumour was reduced by irradiation of the recipients, but significant differences were only evident when cell inocula were large. Isologous tumour resistance was found to become of progressively greater significance with larger numbers of radiation-killed cells. Host-resistance factors appear to increase apparent shoulder size (or extrapolation number), decrease D0, and convert a linear exponential survival curve to a more parabolic one. Host-resistance factors may contribute to cell-survival response in vivo with...

Quantitative study of isologous tumor cell inactivation and effective cell fraction for the LSA mouse lymphoma.

When irradiated, prednisolone‐treated isologous mice were challenged by small numbers of syngeneic tumor cells, most of them developed tumor takes. However, when nonsuppressed animals were challenged by the same cells, few tumor takes developed in an observation period of 160 days. This indicates that small numbers of syngeneic tumor cells can be recognized and eliminated by the normal adult recipient. The results are consistent with a similar effective fraction for different inoculum sizes under the experimental conditions.

Effect of Chemotherapy and/or Head Irradiation on Survival of Mice with Intracranial Glioma

Mice bearing intracranial gliomas were treated with BCNU (1,3-bis(chloroethyl)-l-nitrosourea), Ara-C (cytosine arabinoside), and copper hematoporphyrin with and without head irradiation. The strongest effect was noted with BCNU, as would be expected from brain-barrier and cell age-specific activity of the drug.

Radiotherapeutic response of plasma cell tumors associated with monoclonal gammopathy

Radiation therapy response of localized plasma cell tumors was observed with regard to specific protein synthesis, i.e., monoclonal gammopathy. The patients were well controlled by x‐ray therapy alone, and the disappearance of abnormal proteins in serum was useful to follow response to therapy by monitoring the monoclonal components as well as the radiographs. The course of the disease was characterized by progression and the appearance of multiple lesions.

Calvarial-Scalp Compensator for Radiotherapy

A universal compensator for megavoltage cobalt-60 radiotherapy of the skull was constructed and applied to clinical radiotherapy use. This compensator allows the skull to be treated with a more uniform dose.

Blocking Considerations in Mantle Therapy

The clinical courses of selected patients treated with mantle therapy for Hodgkins disease over a four-year period are outlined, and selected case studies presented. Among patients with mediastinal disease, recurrence was common, mostly in two areas: the geometric penumbra zone of the field or adjacent to the pair of blocks used to protect the lungs from the radiant beam. Individualized shielding, attention to technique, and dosimetry of the field are essential to therapy. A reference point for dosage is useful in specifying prescribed dose. Booster doses relative to the reference dose can be specified but will differ according to the point selected.

Age Cohort Variation of Tumor Cells

The number of cells in the G1, S, G2, or M phase of the cell cycle varies with the stage of tumor growth. During exponential growth, many of the cells take up and are labeled by tritiated thymidine and therefore are in S phase. During the middle stages of tumor growth, the DNA per cell rose and fell coincident with the amount of label uptake. This is consistent with an age cohort composition favoring S, G2, and M phase cells. In the advanced tumor, or terminal animal, cell proliferation was greatly reduced and most of the cells appeared to collect in the G1 phase. Antimetabolite therapy with hydroxyurea and 5-fluoro-uricil was most effective when DNA synthetic activity was greatest.

Analogies between experimental and human lymphoma cutis.

An experimental model system of cutaneous lymphoma has been developed in an inbred mouse system. This utilizes skin isografts from donors which received transplants earlier of a passage ascites lymphoma. Tumor develops in the graft site and follows a development pattern which shows many analogies with human lymphoma cutis.

An individualized water phantom.

Abstract An individualized water phantom with a complex shape is described. This phantom may be used to determine radiation dose distribution for optimized treatment planning.