A sensitive method for evaluating condoms as virus barriers.

A standard test is needed to evaluate condoms as barriers against sexually transmitted diseases, particularly those caused by viruses. The proposed method presented here consists of a previously published simple method using physiologic-based conditions plus improvements to increase test sensitivity and decrease confounding factors such as contamination. Limitations of the method were determined by measuring virus penetration through small, well-defined holes. The method can detect penetration of 2 nL (2 x 10(-6) mL) of challenge virus suspension as well as a hole of 2 microns diameter in a latex condom. The data also indicated that virus penetration of latex condoms occurred quickly, and the hole was then apparently closed or blocked.

PIP: Condoms can act as barriers to the passage of sexually transmitted diseases (STDs). However, a claim that condoms are effective against STDs must be confirmed by appropriate laboratory tests. Various tests have therefore been developed to evaluate the barrier effectiveness of latex and natural membrane condoms. The authors describe and evaluate a test which involves filling the condom with virus-containing buffer and determining whether any virus penetrates the barrier during submersion in a collection buffer. Virus penetration is measured and reported as the equivalent volume of challenge virus suspension needed to account for the amount of virus penetration. The limitations of this approach were determined by measuring virus penetration through small, well-defined holes. It was found that the method can detect penetration of 2 nl of challenge virus suspension as well as a hole of 2 mcm diameter in a latex condom. The data also indicate that virus penetration of latex condoms occurs quickly, then the hole apparently closes or is blocked.

A patient-equivalent attenuation phantom for estimating patient exposures from automatic exposure controlled x-ray examinations of the abdomen and lumbo-sacral spine.

The Joint Commission on Accreditation of Healthcare Organizations requires diagnostic radiology facilities to known the approximate amount of radiation received by an average patient during radiographic examinations at the facility. Automatic exposure controlled (AEC) techniques are used for many of these exams, and a standard patient-equivalent phantom is necessary when estimating patient exposure on such systems. This is of particular importance if exposures are to be compared among AEC systems with different entrance x-ray spectra. We have developed a phantom, LucA1 Abdomen, to facilitate determining the average patient exposure from AEC anteroposterior (AP) abdomen and lumbo-sacral (LS) spine radiography. The phantom is relatively lightweight, transportable, sturdy, and made of readily available inexpensive materials (Lucite and aluminum). It accurately simulates the primary and scatter transmission through the soft tissue and L-4 spinal regions of a patient-equivalent anthropomorphic phantom for x-ray spectra typically used in abdomen/LS spine radiography. A clinical evaluation to verify the patient-equivalence of three commercial anthropomorphic phantoms (Humanoid, Rando, 3-M) and two acrylic/aluminum phantoms (ANSI and LucA1 Abdomen) has been conducted. The design and development of the LucA1 Abdomen phantom and the evaluation of all phantoms is described.

Beam quality independent attenuation phantom for estimating patient exposure from x-ray automatic exposure controlled chest examinations.

The periodic assessment of exposures in diagnostic radiology is an important part of a comprehensive quality assurance program. The most frequent radiologic examination conducted in the United States is chest radiography. Automatic exposure controlled (AEC) techniques are often used for this exam, and a standard patient-equivalent chest phantom is useful when estimating patient exposures on such systems. This is of particular importance if exposures are to be compared among AEC systems with different entrance x-ray spectra. Such a phantom has been developed to facilitate surveys of the average patient exposure from AEC posteroanterior chest radiography. The phantom is relatively lightweight and easily transportable, sturdy and made of readily available and relatively inexpensive materials (Lucite and aluminum). It accurately simulates the primary and scatter transmission through the lung-field regions of a patient-equivalent anthropomorphic phantom for x-ray spectra typically used in chest radiography. A clinical evaluation has been conducted to verify the patient equivalence of the phantom. Measurements of patient entrance skin exposure were obtained for a large number of patients on a variety of x-ray systems operated in the AEC mode using one or both lung-field detectors. Comparison of these data with exposure estimates derived from the phantom indicate that the phantom attenuates the x-ray beam in such a way that it can be employed to accurately and consistently estimate the mean exposure of the average patient under a variety of radiographic conditions. The design, development, and evaluation of the patient-equivalent attenuation phantom is described.