Notes
Notes - notes.io |
Xray photons are higly energetic ionizing radiation. Diagnostic xrays are extremely short = between 10^-8 && 10^-12m in wavelength. THE UNIT formerly used ANGSTROM ==> 1A= 10^-10m
tissue damage can manifest within days. late effecs: Cancer takes years to develop
greatest exposure is from backfground rad.
daignostic xrays produced when high speed electrons are rapidly decelerated by tungsten target @ the focal spot The KINETIC ENERGY of the electrons is CONVERTED TO X-RAY PHOTON ENERGY.
SOURCE OF ELECTRONS: heated cathode filament
2 WAYS OF CONVERTING:
BREMSSTRAHLUNG or braking radiation: 70-90% of the beam
CHARACTERISTIC RADIATION knocks kshell electron and a higher energy level replaces it. when it replaces it there is a difference of energy, whatever is left over after going down 1 level is emitted as xray. 10-30%of the beam
INTERACTIONs between xray photons and matter - the decrease in exposure rate as ionizing radiation passes through tissue is called attenuation
1) PHOTOELECTRIC EFFECT- low energy xray photon interacts with tissue and uses all its energy to eject an inner shell electron. this leaves an inner shell orbital vacancy so a electron from a shell above drops down to fill the vacancy, when doing this the higher shell electron gives up energy gy in the form of characteristic ray to fit. This is more likely to occur in absorbers having HIGH ATOMIC NUMBER (bone, positive contrast media) and with low energy photons. PE contributes significantly to patient dose.
2)COMPTON SCATTER - HIGH energy xray photon interacts with tissue and ejects an outer shell electron. The ejected electron is called a COIL ELECTRON. The scattered electron is deflected with somewhat re3duced energy but retains most of its original energy and exits the body as an energetic scattered photon. Because the photon exits the body, it does not pose a radiation hazard to the patient. It can contribute to image fog and poses a radiation hazard to personnel= EX: FLUOROSCOPIC PROCEDURES.
all radiations in the EM spectrum travel at the speed of light 186000 miles/s, differ in wavelength & frequency.-+
Dose response pg 230
|
|
Notes.io is a web-based application for taking notes. You can take your notes and share with others people. If you like taking long notes, notes.io is designed for you. To date, over 8,000,000,000 notes created and continuing...
With notes.io;
- * You can take a note from anywhere and any device with internet connection.
- * You can share the notes in social platforms (YouTube, Facebook, Twitter, instagram etc.).
- * You can quickly share your contents without website, blog and e-mail.
- * You don't need to create any Account to share a note. As you wish you can use quick, easy and best shortened notes with sms, websites, e-mail, or messaging services (WhatsApp, iMessage, Telegram, Signal).
- * Notes.io has fabulous infrastructure design for a short link and allows you to share the note as an easy and understandable link.
Fast: Notes.io is built for speed and performance. You can take a notes quickly and browse your archive.
Easy: Notes.io doesn’t require installation. Just write and share note!
Short: Notes.io’s url just 8 character. You’ll get shorten link of your note when you want to share. (Ex: notes.io/q )
Free: Notes.io works for 12 years and has been free since the day it was started.
You immediately create your first note and start sharing with the ones you wish. If you want to contact us, you can use the following communication channels;
Email: [email protected]
Twitter: http://twitter.com/notesio
Instagram: http://instagram.com/notes.io
Facebook: http://facebook.com/notesio
Regards;
Notes.io Team
