Feasibility Study of Vertical Multileaf Collimator for Determination of Irradiation Size / 의학물리

The purpose of this study was to evaluate feasibility of Vertical Multileaf Collimator for determination of irradiation size using Vertical Multileaf Collimator and lead block to determine 4 different irradiation shape in case of Co-60 gamma-ray and 6 MV X-ray. We chose ion chamber, glass dosimeter and EBT chromic film to compare with Vertical Multileaf Collimator results and lead block results. In case of Co-60 gamma-ray and 6 MV X-ray, the central axis point dose normalized at reference field of lead block with ion chamber results for Vertical Multileaf Collimator were estimated higher than lead block about 5.1%, 4.2%. In case of Co-60 gamma-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 2.2%, 7.8%, 7.2%, 4.0% for reference, circle, triangle, cross field, respectively. In case of 6 MV X-ray, the central axis point dose normalized at reference field of lead block with glass dosimeter results for Vertical Multileaf Collimator were estimated higher than lead block about 6.7%, 6.2%, 3.8%, 6.2% for reference, circle, triangle, cross field, respectively. The results of EBT chromic film, Vertical Multileaf Collimator of penumbra size for all irradiation shape was smaller than lead block of those size that 2.0~3.5 mm for Co-60 gamma-ray, 0.5~1.0 mm for 6 MV X-ray. The results from this study, radiation treatment volume that results in shielding block can be minimized. In addition, during radiation treatment for 2, 3-dimensional radiation therapy using a Vertical Multileaf Collimator of this survey can be used to determine variety of irradiation fields.

Delivery of Photosensitizers for Photodynamic Therapy / 대한소화기학회지

Photodynamic therapy (PDT) has been used to treat several types of cancer, and comprises intravascular administration of photosensitizer, uptake by cancer cells, and followed by irradiation of light of appropriate wavelength. Although PDT takes advantage of relative retention of photosensitizer by cancer cells, effective delivery of photosensitizing drugs is of great concern. Several delivery strategies have been employed in PDT. Photosensitizers can be delivered either by passive carriers such as liposomes, micelles, and polymeric particles, or by active targeting using cancer cell-directed ligands or antibodies. Although well-studied colloidal carriers effectively deliver photosensitizer to tumor cells, they are taken up by mononuclear phagocytic system. Delivery system using polymers is an attractive alternative to colloidal carriers, in which hydrophobic drugs are chemically or physically loaded to polymers. Though there are several steps to be solved, targeted delivery system utilizing receptors or antigens abundantly expressed on cancer cell theoretically provides a great deal of advantages over passive system. Selective uptake of photosensitizers by cancer cells may greatly enhance therapeutic efficacy as well as minimizing adverse effects resulting from accumulation in normal tissue. This review discusses various strategies for photosensitizer delivery that have been investigated to date.

Gene Expression Profiles in Pancreatic Intraepithelial Neoplasia Reflect the Effects of Hedgehog Signaling on Pancreatic Ductal Epithelial Cells. Cancer Res 2005;65:1619-1626 / 대한소화기학회지

No abstract availble.