Asymmetric breast dose in coronary angiography.

The purpose of this study was to demonstrate asymmetric radiation dose distribution to the breasts in coronary angiography. Gafchromic XR-QA2 film was used as an area dosimeter to capture the asymmetric dose distribution to the breasts at various tissue depths in an anthropomorphic phantom. A selection of tube angulations were used under a controlled experiment and during a mock coronary angiography procedure. The Gafchromic XR-QA2 film was able to confirm the asymmetric distribution of radiation dose to the breast and provide a normalized breast dose value. The right breast received the majority of dose for most of the tube angulations in the controlled experiment. However the left breast received the most radiation dose during the mock procedure. Asymmetric dose distribution to the breasts is normally not observed if Monte Carlo based simulations are performed because individual breast dose calculations are not available. The application of a typical coronary angiogram determined in the experiment showed the normalized left breast dose is 0.16 mGy/ Gy.cm2 and the right breast dose is 0.08 mGy/ Gy.cm2.

An assessment of nursing staffs' knowledge of radiation protection and practice.

Although the exposure to nursing staff is generally lower than the allowable radiation worker dose limits, awareness and overcoming fears of radiation exposure is essential in order to perform routine activities in certain departments. Furthermore, the nursing staff, whether they are defined as radiation workers or not, must be able to respond to any radiological emergencies and provide care to any patient affected by radiation. This study aims to gauge the awareness of radiation safety among the nursing staff at a major hospital in different departments and recommend if further radiation safety training is required. A prospective multiple choice questionnaire was distributed to 200 nurses in 9 different departments. The questionnaire tested knowledge that would be taught at a basic radiation safety course. 147 nurses (74%) completed the survey with the average score of 40%. Furthermore, 85% of nurses surveyed felt there was a need for radiation safety training in their respective departments to assist with day to day work in the department. An increase in radiation safety materials that are specific to each department is recommended to assist with daily work involving radiation. Moreover, nursing staff that interact with radiation on a regular basis should undertake radiation safety courses before beginning employment and regular refresher courses should be made available thereafter.

Computed tomography overexposure as a consequence of extended scan length.

INTRODUCTION: This study aimed to raise awareness around the increased effective dose as scan length chosen is increased from standard protocol METHODS: The Monte Carlo-based software CT-Expo (G. Stamm (Medizinische Hochschule Hannover, Hannover, Germany) and H.D. Nagel (SASCRAD, Buchholz, Germany)) was used to simulate the effective dose increase as the scanned region of the standard protocol increased. RESULTS: The results of this study show that for scans with a high computed tomography dose index (CTDI)vol the patient could be exposed to an extra 1 mSv within 6 cm of overscan. Protocols that investigated large scan areas may not see a significant relative dose reduction because of the use of a lower CTDIvol ; however, radiation exposure should be kept as low as reasonably achievable. CONCLUSION: There is significant dose optimisation potential when strictly adhering to appropriate scan lengths within each imaging protocol wherever possible.

Effects of radiographic techniques on the low-contrast detail detectability performance of digital radiography systems.

PURPOSE: To evaluate the effects of the radiation exposure factors kilovolt peak and tube current time (milliampere seconds) on the low-contrast detail detectability performance of 3 types of planar digital radiography systems. Detectability performance of an imaging system refers to its ability to detect and present the low-contrast details of organs in the acquired image. The authors also compare detectability performance between computed radiography, indirect digital radiography, and direct digital radiography by evaluating low-contrast details of the obtained images. METHODS: A low-contrast detail phantom was inserted within 10-cm thicknesses of Perspex plastic sheets. The images were obtained with various kilovolt peak and milliampere second settings for each of the 3 digital radiography systems. Artinis CDRAD Analyser software was used to score the images and calculate the inverse image quality figure (IQFinv). RESULTS: The higher milliampere second levels in each kilovolt peak selection resulted in higher IQFinv in computed radiography and indirect and direct digital radiography. IQFinv values significantly increased in indirect digital radiography with increasing kilovolt peak in only 1 and 2 mAs. There were insignificant differences in IQFinv values when altering kilovolt peak in each milliampere second level in direct digital radiography. The indirect digital radiography system generally demonstrated better detectability performance than computed radiography and direct digital radiography. However, direct digital radiography demonstrated better detectability performance than indirect digital radiography at lower kilovolt peak and milliampere second settings, as did computed radiography at lower kilovolt peak settings. DISCUSSION: Higher milliampere second settings increase photon count, which results in a higher signal-to-noise ratio and thus increased detectability. Lower milliampere second settings increase noise level on images, which increases the risk of diagnostic detail loss. Changing the kilovolt peak at the different milliampere second settings essentially did not affect the IQFinv of the different digital radiography systems. CONCLUSION: Increasing milliampere seconds in all digital imaging systems generally improves detectability performance. However, altering the kilovolt peak setting does not significantly change the IQFinv and detectability of objects in a digital radiograph. Imaging system selection should be based on typical radiographic examinations. Indirect digital radiography systems are better for studies that require higher kilovolt peak, such as large organs, and direct digital radiography is better for studies that require low kilovolt peak, such as small organs and mammography, which is used to examine fine tissue details.