Effect of edema, relative biological effectiveness, and dose heterogeneity on prostate brachytherapy.

Many factors influence response in low-dose-rate (LDR) brachytherapy of prostate cancer. Among them, edema, relative biological effectiveness (RBE), and dose heterogeneity have not been fully modeled previously. In this work, the generalized linear-quadratic (LQ) model, extended to account for the effects of edema, RBE, and dose heterogeneity, was used to assess these factors and their combination effect.

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.

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).

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.

Use of isotonic water-soluble contrast agents for gastrointestinal examinations in infants.

Ten percent sodium diatrizoate, which is approximately isotonic with plasma, can be used with 60 kV radiography/fluoroscopy to visualize the stomach, small intestines, and colon of young infants.

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.

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.