Question

In: Chemistry

Is the visual appearance of an image a reliable indicator of overexposure? Why/why not ? How...

Is the visual appearance of an image a reliable indicator of overexposure? Why/why not ? How could this negatively affect the patient?


-How images suffer from a loss of diagnostic quality due to excessive exposure? Explain.




(Radiologic question)

Solutions

Expert Solution

Solution:

Yes, the visual appearance of an image is a reliable indicator of overexposure when using conventional film-screen radiography technique. The noise level in the film-screen radiography is determined primarily by the receptor sensitivity (or speed). That is determined by the design characteristics of the intensifying screens and film used.
When using a film-screen receptor the exposure must be set to match the sensitivity of the receptor or the results will be either and underexposed (light film) or overexposed (dark film) image. Therefore, all acceptable films, from an exposure and contrast perspective, will be produced with a receptor exposure that is determined by the sensitivity characteristic of the receptor. The noise level can only be changed by changing the receptor, typically by changing the film to one with a different sensitivity (speed).

In film-screen radiography it is important that appropriate exposure and technique factors be used for imaging process. An optimum (correct) exposure is one that produces an image with an acceptable noise level without unnecessary or excessive exposure to the patient. In radiographic systems display, along with the image, and indication of the amount of exposure used to form the image. The sensitivity, "S" factor is used to indicate the effect sensitivity (speed) used by the system for that specific image. A high S factor (=1000) indicated the image was formed with a low exposure and excessive noise would be expected. A low S factor (=50) indicates and unnecessarily high exposure of radiation to the patient was used. The image quality is good because of the low noise but the patient was subjected to unnecessary exposure and this is a negative effect to the patient.

Images suffer from a loss of diagnostic quality due to excessive exposure because of low sensitivity of the receptor and high quantum noise. Radiographs recorded on film with deviation from the optimum exposure resulted in under-exposed (light) or over exposed (dark) films.


Related Solutions

How is an image organized in the lateral geniculate nucleus, the primary visual cortex?
How is an image organized in the lateral geniculate nucleus, the primary visual cortex?
Share and describe an image that depicts a visual representation of data. Briefly explain why you...
Share and describe an image that depicts a visual representation of data. Briefly explain why you think this representation is particularly interesting or effective. You can create your own representation or find an example. Please, be sure to cite the source in your description if the image is not your own.
Share and describe an image that depicts a visual representation of data. Briefly explain why you...
Share and describe an image that depicts a visual representation of data. Briefly explain why you think this representation is particularly interesting or effective. You can create your own representation or find an example. Please, be sure to cite the source in your description if the image is not your own.
Share and describe an image that depicts a visual representation of data. Briefly explain why you...
Share and describe an image that depicts a visual representation of data. Briefly explain why you think this representation is particularly interesting or effective. You can create your own representation or find an example. If the image is not your own, be sure to cite the source in your description. eg. scatter plot etc
Is a rule's frequency a reliable factor to determine how effective it is? Why or why...
Is a rule's frequency a reliable factor to determine how effective it is? Why or why not? Provide an example to support your answer.
in visual C# Total Sales This is the design of the application. This image shows the...
in visual C# Total Sales This is the design of the application. This image shows the application’s form when it starts running and processes the data in the file: You are tasked with creating an application that reads a file’s contents (File: Sales) into an array, displays the array’s contents in a ListBox control (Chapter 4), and calculates and displays the total of the array’s values. You will use a loop (Chapter 5) to read in the data from the...
Body mass index (BMI) is a reliable indicator of body fat for most children and teens....
Body mass index (BMI) is a reliable indicator of body fat for most children and teens. BMI is calculated from a child’s weight and height and is used as an easy-to-perform method of screening for weight categories that may lead to health problems. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. The Centers for Disease Control and Prevention (CDC) reports BMI-for-age growth charts for girls as well as boys to obtain a...
What role, if any does media play in shaping a woman’s self-image regarding the appearance of...
What role, if any does media play in shaping a woman’s self-image regarding the appearance of her genitals? Be sure to discuss the relatively new cultural phenomenon of shaving or waxing one’s pubic region and/or genital piercings. Explain why male size has historically been so important and how it has affected men’s masculinity and/or self-image. Describe penile augmentation procedures. Males tend to be more comfortable with their genitals than females are with their genitals. This in part accounts for the...
How does indicator works and how does one select an indicator?
How does indicator works and how does one select an indicator?
Explain why this is interesting. I was tasked to provide a summary of how reliable is...
Explain why this is interesting. I was tasked to provide a summary of how reliable is an inverted curve in anticipating a recession; and to also discuss the variability of a yield curve and a subsequent recession. In researching the 10-year Treasury Yield, and the three-month Treasury Bill Rate and graphing it, the data was interesting. During periods of non-recession it seems both statistics are similar and related. I wasn’t aware until the reading the text, that the relationship between...
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT