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Biomedical subjects

C Kanellitsas

Publications and source records attributed to C Kanellitsas.

9 recordsLinked to original sources
PubMed1990

Theoretical basis and clinical methodology for stereotactic interstitial brain tumor irradiation using iododeoxyuridine as a radiation sensitizer and 145Sm as a brachytherapy source.

A technique to produce radiation enhancement during interstitial brain tumor irradiation by using a radiation sensitizer (iododeoxyuridine-IdUrd) and by stimulation of Auger electron cascades through absorption of low-energy photons in iodine is described. Clinical studies using iododeoxyuridine, 192Ir as a brachytherapy source, and external radiation have produced promising results. Substituting 145Sm for 192Ir in this protocol is planned to evaluate the enhanced dose resulting from photon activation therapy.

Brachytherapy↗
PubMed1987

Samarium-145: a new brachytherapy source.

A new radiation source has been produced for brachytherapy, with radiation energies slightly above those of 125I, and a T1/2 of 340 d. This source, 145Sm, is produced by neutron irradiation of 144Sm (96.5% enriched). Decay is by electron capture with 140 K x-rays per 100 disintegrations in the energy region between 38-45 keV, plus 13 gamma-rays at 61 keV. These sources are encapsulated in Ti tubes, approximately 0.8 mm X 4.5 mm, and have been developed for temporary implantation in brain and ocular tumours. The 38-61 keV photons should make such sources easy to shield, while providing a dose distribution from source arrays somewhat more homogeneous than that from 125I. In addition, the 340 d half life of 145Sm permits its use for times significantly longer than that of 60 d 125I. While the 145Sm sources have been designed primarily for implantation in a brain tumour, they should be useful for almost any conventional brachytherapy application.

Brachytherapy↗
PubMed1987

Single-scan stereotactic tumor biopsy and brachytherapy.

Stereotactic tumor biopsy and brachytherapy catheter implantation can be accomplished with targets derived from computed axial tomography and magnetic resonance scans. Computer manipulation of image data allows both diagnostic and therapeutic procedures to be carried out from a single set of scan slices. This eliminates the need for repeat scanning as part of the surgical procedure. Microcomputer technology is sufficiently advanced to handle the images and graphics necessary for stereotactic neurosurgery. A system based on the IBM PC/AT designed for this purpose uses readily available graphics software and custom-designed imaging programs. Direct loading of computed axial or magnetic resonance scan images from magnetic tape can be accomplished. Determination of points, contours and volumes in three-dimensional space allows intraoperative alignment of image data and patient landmarks within the stereotactic head frame using pattern recognition overlays. Three-axis scaling for magnification correction along with rotational and linear data transformations provide the basis for single-scan stereotaxis. Interactive computer graphics integrate image, patient and frame coordinates for target determination. This method eliminates the need to design and fabricate nonmagnetic or radiolucent scanner-compatible devices.

Biopsy↗
PubMed1976

An after loading colpostat (using standard source tubes).

An afterloading system for the treatment of gynaecological patients is described. It uses a rigid tandem to which afterloading colpostats are attached. The catheters for afterloading the colpostats are flexible thus minimizing patient discomfort. A constant 90 deg. alignment of source tubes between the uterine tandem and colpostats is achieved.

Cesium Radioisotopes↗
PubMed1975

Analytical approach for depth dose calculations (60Co beams with fixed source-target distance).

A method is described to calculate depth dose distribution to a principal plane using analytical formulas for 60Co teletherapy units and constant source-to-target distance. The formulas were derived from experimental measurements taking into consideration the obliquity of the beam. For the purposes of dose calculation the beam was divided into primary and scattered components. A computer program incorporating the formulas was developed for an IBM 360/67 computer. Dose distributions computed and obtained from experimental measurements were in good agreement. The computer program is now in use for treatment planning, including rotational techniques.

Cobalt Radioisotopes↗