Large-body radiation doses following radioiodine therapy.

In accordance with the recommendations of the International Radiological Protection Commission, the current maximum acceptable radiation dose limits for members of the public have been reduced to 1 mSv in the United States, Canada, and European Union countries including the United Kingdom. This has had a significant impact on radiation protection guidelines for contacts of patients treated with 131I. Many previous recommendations have relied upon models which may overestimate dose rates at short distances.

Three-dimensional lithographic model building from volume data sets.

Computed tomographic images of a dry human skull and an in-situ knee joint were used to construct solid three-dimensional polymer models using stereolithographic techniques that have been introduced recently into the manufacturing industry. The stereolithographic technique makes use of a computer-steered narrow laser beam to solidify the model within a bath of liquid photocurable polymer. The method does not suffer from the cutting-tool size and path constraints encountered in the more commonly used process of machining the models from a solid block of foam.

Radiation doses and detriment from chest x-ray examinations.

Radiation dose distributions for chest x-ray examinations have been measured in a Rando phantom for three views (AP, PA and lateral) as a function of kVp. On the basis of these data, the relationship between the surface dose, energy imparted and the effective dose equivalent have been determined. The mean energy imparted in a typical chest examination (PA + lateral views at 100 kVp) is 1.

Some factors affecting the calibration of radionuclide calibrators--I. 99mTc.

In the Winnipeg area a centralized radiopharmacy serves several Nuclear Medicine departments supplying all their 99mTc radiopharmaceuticals on a daily basis. It was observed that there was very poor consistency between the assays as determined by the Radiopharmacy and those determined in the various Nuclear Medicine departments. An attempt to "correct" the various calibrators using a 57Co "mock" 99mTc source resulted in an aggravation of the problem, and an investigation of relative responses of various calibrators to the "mock" relative to a 99mTc source was undertaken, together with an investigation of the influences of various environmental conditions on the calibrator function.

Xenon-133 ventilation and perfusion studies in bronchiectasis.

Thirty-nine Xenon-133 ventilation and perfusion studies in 36 patients with bronchiectasis were analyzed retrospectively. These patients showed a marked reduction in ventilation with a less severe reduction in pulmonary arterial perfusion, resulting in areas of low ventilation-perfusion ratios. In those patients with bronchographic confirmation, xenon studies had greater sensitivity (0.

Quantitation of fat in liver by xenon uptake.

Xenon uptake in fatty livers of seven patients has been quantitatively measured, and correlated with the amount of fat in the hepatic cells. Quantitation of the Xenon uptake correctly predicted the amount of fat seen histologically in six of the seven patients studied. In the seventh patient, analysis of the wash-in and wash-out curves showed that equilibrium conditions had not been reached.

Telephone line transmission of rectilinear radionuclide scans. Report of a pilot project.

The General Electric-Elscint system for telephone line transmission of rectillinear scans has been tested and with certain limitations found to be acceptable in terms of diagnostic accuracy for many scan procedures. The system tested had some logistic disadvantage requiring batch processing of the scans, and making quality control of the scans difficult with the one video data processor available at the reference centre.

Hidden-part suppression on three-dimensional plots.

The conceptual and mathematical description of a method to draw a three-dimensional histographic surface in oblique projection, with the drawing of hidden parts suppressed, is given.