Local irradiation

Lucentis contains ranibizumab and is available for intravitreal injection. It is a vascular endothelial growth factor inhibitor indicated for the treatment of neovascular (wet) age-related macular degeneration. Unlike verteporfin, which is used in photodynamic treatment of age-related macular degeneration, ranibizumab does not require activation by local irradiation using non-thermal red light. 

Early breast cancer is usually treated by surgery and local irradiation. Hormonal therapy is reserved for patients with advanced metastatic breast cancer. Breast cancer occurs in both premenopausal and postmeno-... 

Liver cancer can be induced in rats by localized irradiation (UNSCEAR, 1977) or by a number of different chemicals and dosage schedules (Farber, 1984). Initiation-promotion protocols are also effective inducers of liver tumors. The predominant lesions are preneoplastic nodules, but as in the skin, carcinomas arise late in the process. Altered hepatic cell fod can be identified within a few weeks after the start of carcinogen treatment by specific changes in enzyme activity, inability... 

More recently, Sugiura et al.11 developed a fully functional microvalve based on this photoresponsive behavior, which was composed of poly(/V-isopropylacrylamide) functionalized with the chromophore spirobenzopyran (pSPNIPAAm). The microvalve was fabricated in a polydimethylsiloxane (PDMS) microchannel by in situ photopolymerization. Blue light irradiation (18 to 30 s) to the gel induced photoisomerization of the spirobenzopyran chromophore which resulted in shrinkage due to dehydration of the gel, thus causing the microvalves to open, as seen in Figure 23.7. In this example, localized irradiation enabled independent control of three photoresponsive polymer gel microvalves, which had been fabricated on a single microchip. 

The treatment of choice for leukemia is chemotherapy, but because of the blood-brain barrier cytotoxic drugs are ineffective in treating leukemic optic neuropathy. Radiotherapy is the preferred treatment for the optic neittopathy because the optic nerve is relatively insensitive to radiotherapy but the leukemic cells are very radiosensitive. Chemotherapy and local irradiation have not shown promise in the treatment of lymphomatous optic neittopathy Meningiomas, likewise, are insensitive to chemotherapy and irradiation and require surgical excision. 

Figure 2. Scanning vibrating electrode iiKasuranents (SVET) of the ionic currents above the surface of SiOx ZrOx film with BSA-loaded TiOi-based polyeleclrolyte nanocontainers (a) after immersion for 36 hours in 0.1M NaCl (b) after local irradiation with IR laser of the corrosion area...

A gradient in cross-linking density and therefore regions with different swelling behaviour can be generated by a consecutive spatially localized irradiation of a precross-linked layer through a mask. 

Chromic is a radiopharmaceutical. It causes local irradiation by beta emission. Chromic phosphate P32 decays by beta emission with a physical half-life of 14.3 days. It is used in the treatment of peritoneal or pleural effusion caused by metastatic disease. 

Sodium iodide I is a radiopharmaceutical/antithyroid agent. After rapid GI absorption, iodine I is primarily distributed within extracellular fluid. It is trapped and rapidly converted to protein-bound iodine by the thyroid it is concentrated, but not protein bound, by the stomach and salivary glands. It is promptly excreted by kidneys. About 90% of the local irradiation is caused by beta radiation and 10% is caused by gamma radiation. I has a physical half-life of 8.04 days. It is indicated in the treatment of thyroid carcinoma, hyperthyroidism. 

Few commercial uses exist for the radioactive decay products of uranium. The highly radiotoxic Ra was used in luminous paint on watch and instrument dials and, during the 1920s and 1930s, was also widely used in radiotherapy to treat tumors as well as therapy for diabetes, sciatica, uremia, rheumatism, and even impotence (Genet 1998). The radium decay product, Rn, with its half-life of 3.8 days is still used, after sealing it in minute tubes called seeds or needles, for local irradiations in patients. 

In some cases, local irradiation of some tissues is produced by the use of radioactive nuclides inmlanted in the tissue by means of needles or small capsules. For example, needles of "Sr— Y, pellets of Au, etc., have been inqilanted in the pituitary gland (for acromegalia, Cushing s disease, and cancer), in the breast (for breast cancer), in the prostate, and in the nerves (to reduce pain). The local dose may be lOO s of Sv. Also, radioactively labeled tumor seeking compounds are used. 

Anderson E, Holland L, Prine J, et al. 1977. Lung response to localized irradiation from plutonium microspheres. In Walton W, ed. Inhaled Particles. Vol 4. New York Pergamon Press, 615-623. 

Saenger, E.L., Acute local irradiation injury, in Proc. REACTS Int Conf Medical Basis for Radiation Accident Preparedness, Hubner, K.F., and Fry, S.A., Eds., Elsevier/NorthHoUand, 1980. 

Integration of L z,(o) over the directions 0) yields the local irradiance G(z) ... 

In Section 3, we estimate the local irradiance G(xq) by the same algorithm, only replacing Wj with the new weight function... 

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