Factors influencing oestrogen-induced sensitization to acetylcholine of guinea-pig uterine artery.
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Acetylcholine↗
Biomedical subjects
C Coffey
Publications and source records attributed to C Coffey.
An intercomparison between two methods of obtaining percentage depth doses for irregular shaped fields and comparison of each method with experimental data for 60Co and 10 MV X rays.
Measurements of central ray tissue-air ratio (TAR) for 60Co for a large number of irregularly shaped fields typically encountered in the cancer clinic were compared with TAR values either calculated by the Clarkson method using scatter air ratios or obtained from tables of square field data using the area/perimeter approach. Irregular field shapes included the "L", pentagonal, rectangular, upper and lower mantle and split fields. Agreement between both calculational methods and direct measurement is within +/- 2% if careful attention is given to central ray position as affected by the proper use of off-centre ratios in air. In the case of 10 MV X-rays, eight randomly chosen irregular fields again yielded an average agreement between both methods of calculation and experimental data of less than 1% and an agreement of less than 0.5% between the A/P and Clarkson calculations.
Cobalt Radioisotopes↗
Method for localizing and calculating vaginal dose in brachytherapy.
Contrast agents in the vagina are being used to determine the position of vaginal surfaces relative to applicators in an effort to assess dose at these sites. Computer treatment planning allows consideration of dose at many more sites than was formerly possible, but dose prescription to critical tumor volumes then becomes of greater importance. Vaginal reference dose points VR, VL, VA, and VP are proposed. With dose specification determined at these points, the problem of low vaginal dose from overly wide vaginal ovoid geometries and related difficulties can be avoided. Attention to central vaginal doses can reduce the probability of central pelvic recurrence in the vagina. We have found the VR, VL doses were much larger than VA, VP doses in standard loaded implant configurations.
Aged↗
Enhancement of radiation effect on mouse intestinal crypt survival by timing of 5-fluorouracil administration.
There is a marked dependence of mouse crypt survival on the sequence of combined drug-radiation treatment and on the time lapse between irradiation and drug administration. When 5-fluorouracil is administered 6 hours after irradiation or later (up to 18 hours postirradiation), crypt survival drops significantly.
Animals↗
Approaches to optimization of dose in radiation therapy of cervix carcinoma.
A treatment planning approach to radiation therapy for carcinoma of the cervix which attempts to maximize tumor dose and minimize the effect on normal tissue must include additonal dose reference points besides the standard ones (Manchester points A and B, mg-hrs.) A variety of loading configurations can be used to treat the tumor volume to a specified dose. In order to avoid inappropriate loading arrangements, dose at the tumor and at the vault must be carried to required therapeutic levels.
Female↗
Experimental investigation of source-block distance to source-surface distance ratios for cuboid and beam-divergence-shaped shadow blocks for cobalt-60 teletherapy.
The partial transmission zone (PTZ) measured in air and its radiation shadow components are identified quantitatively and qualitatively for both cuboid and beam-divergence-shaped blocks. Source-block distance (SBD) and source-surface distance (SSD) are varied to produce SBD/SSD ratios from 0.71 to 0.86. The variation of the magnitude of the radiation shadow components as a function of SBD/SSD is explained in terms of a radiation shadow model. The clinical significance of PTZ minimization and a comparison between PTZs of 'shaped' and 'nonshaped' blocks is discussed. For small ratios of SBD/SSD the beam-divergence-shaped blocks produce smaller medial and lateral PTZs, whereas for larger ratios in the order of 0.9 the medial PTZ is also small for the cuboid blocks. Both PTZs, in general, decrease with increasing SBD/SSD ratios and for both cuboid and beam-divergence-shaped blocks.
Cobalt Radioisotopes↗