It is well known that the response of tumors to radiotherapy is closely related to the changes in vascular circulation during the course of treatment. An in-crease in vascular function and blood supply may enhance oxygenation of tumors and thus increase the radiosensitivity of surviving tumor cells to subsequent irradiation, whereas extensive radiation-induced vascular damage would result in poor oxygenation of the tumor, making the tumor cells radioresistant.
Up to date, a number of investigators have studied on the vascular damage in irradiated tumors of breast and liver, but reports on the salivary gland tumors were hardly seen. Recently, microangiography has been introduced in the study of normal vascular arrange ment. ""´
Tumors of mice or rats extensively studied by microangiography have appeared to have the characteristic vascular arrangements´-" But the changes of vascular arrangements in the salivary gland tumor of rats following irradiation were rarely reported.
On experimental tumor of the salivary gland, in 1942, Steiner´ successfully induced squamous cell carcinoma and adenocarcinomas with injection of methyl-
´This article had been presented to the 57th congress of Gifu Dental Society, Japan on 20. June 1987.
`´This research was supported by the Inje Research and Scholarship Fund in 1986 and 1987.
`Department of Oral and Maxillofacial Surges_.. Inie Medical College, Paik Hospital.´ Seoul
cholanthrene, 1,2,5,6,-dibenzanthracene and 3,4-benzopyrene in the salivary gland of the mouse, albino rat, hamster and rabbit. Subsequently, more prompt and creditable methods were developed 8" And made it easier to study the morphology of the tumor, the mechanism of carcinogenesis the histopathologic pattern, the influencing factors of tumorigenesis,´Z.,a"´ and the chemotherapeutic agents. 15.16.17)
Sugimura and Kawakatsu,") and Matsumura"´ studied histochemically the enzymatic pattern of DMBA induced carcinogenesis in mouse salivary gland and tried to clarify the progenitor cells of salivary gland tumors.
To clarify the radiation effect on mierovasculature of DMBA induced rat salivary gland tumor, the author examined the histopathologic findings of microvasculature and microangiography, by barium perfusion and indian ink perfusion technique, in tumors and their surrounding tissues of non-irradiated and irradiated groups.
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