When an x-ray is made, an x-ray beam leaves the x-ray tube, passes through the body and hits a phosphorus plate/detector. The whiteness (= density) depends on the amount of X-ray radiation passing through the tissue (fig. 2).
Figure 2. X-ray densities (= whiteness).
The more X-rays are obstructed (absorbed or scattered) and do not reach the phosphorus plate/detector, the denser (= whiter) the image. Highly absorbent materials, such as metal, will be imaged as dense. Another example: X-rays pass more easily through the air-filled lungs (black) than bone (white). The information received on the plate is converted into a digital image. Correctly imaged, an X-ray provides information on the ossal structures, fluid, air, soft tissue contours and prostheses/osteosynthetic material.
Comments:
Each X-ray is evaluated as if you are standing in front of the patient; so the right side of the image is the patient’s left side and vice versa.
Importantly, the X-ray beam has a divergent property. This means it widens as the distance to the X-ray tube increases. A drawback of this phenomenon is that tissues/structures farther from the plate are imaged larger. This is relevant when evaluating the size of the heart in a chest x-ray (fig. 3).
Figure 3. Effect of the divergent x-ray on the size of the heart (a = posterior-anterior technique, b = anterior-posterior technique).
We, and third parties, use cookies on our website. We use cookies to keep statistics (Google Analytics cookies are completely anonymised), to store preferences, but also for marketing purposes. By clicking on 'set it yourself', you can read more about our cookies and adjust your preferences. By clicking 'Accept and continue' you agree to the use of all cookies as described in our cookie statement.
We, and third parties, use cookies on our website. We use cookies to keep statistics (Google Analytics cookies are completely anonymised), to store preferences, but also for marketing purposes.
Necessary cookies are absolutely necessary for the website to function properly. These cookies provide basic functionalities and security features of the website anonymously.
Cookie
Duration
Description
cookielawinfo-checkbox-analytics
1 year
Set by the GDPR Cookie Consent plugin, this cookie is used to record the user consent for the cookies in the "Analytics" category .
cookielawinfo-checkbox-necessary
1 year
Set by the GDPR Cookie Consent plugin, this cookie is used to record the user consent for the cookies in the "Necessary" category .
cookielawinfo-checkbox-others
1 year
Set by the GDPR Cookie Consent plugin, this cookie is used to store the user consent for cookies in the category "Others".
CookieLawInfoConsent
1 year
Records the default button state of the corresponding category & the status of CCPA. It works only in coordination with the primary cookie.
elementor
never
This cookie is used by the website's WordPress theme. It allows the website owner to implement or change the website's content in real-time.
Analytical cookies are used to understand how visitors interact with the website. These cookies help provide information about statistics, number of visitors, bounce rate, traffic source, etc.
Cookie
Duration
Description
_ga
2 years
The _ga cookie, installed by Google Analytics, calculates visitor, session and campaign data and also keeps track of site usage for the site's analytics report. The cookie stores information anonymously and assigns a randomly generated number to recognize unique visitors.
_gat_gtag_UA_48509342_1
1 minute
Set by Google to distinguish users.
_gat_gtag_UA_48509342_2
1 minute
Set by Google to distinguish users.
_gid
1 day
Installed by Google Analytics, _gid cookie stores information on how visitors use a website, while also creating an analytics report of the website's performance. Some of the data that are collected include the number of visitors, their source, and the pages they visit anonymously.
Menu
Menu
Login
Accessing this course requires a login. Please enter your credentials below!