Linear Energy Transfer(LET) – energy deposited per unit track (the unit being microns).   Kev/u = energy/distance.   If the number of Kev is larger then the larger the value of LET.   If the number of u is larger then the smaller the value of LET.

High LET – slow moving and densely ionizing

Low LET – fast moving and sparsely ionizing

RBE – relative biological effectivness (RBE equals the dose of baseline radiation needed to produce a given effect / the dose of test radiation needed to produce the same effect)

External Beam (EBRT) – A form of  radiation therapy in which radiation is delivered by a machine pointed at the area to be radiated.   There are 3 types of EBRT; short(15cm), medium(50cm), and long(100cm).

Brachytherapy – short distance therapy. A  type of radiation therapy in which radioactive materials are placed in  direct contact with the tissue being treated.  There are 3 types of brachytherapy; Molds and Applicators(obsolete), Intracavitary, and Interstitial.   The advantages of brachytherapy are the sparring of normal tissue and it can be used as a boost with other procedures.   The disadvantages of brachytherapy are it is an invasive procedure, can only be used with small tumors and it does not address nodal involvment.  

Molds and Applicators – is a type of brachytherapy in which a lead mold is filled with sources and then placed on the patient for a set amount of time.   This method is obsolete.

Intracavitary – (within cavity) is a type of brachytherapy in which sources are placed directly inside the patient in an pre-existing cavity (ex. GYN tumors)

Interstitial – is a type of brachytherapy in which sources are placed directly into tissue of the patient.   The sources can be permanent or temporary depending on the accessibility to the site.

Thermionic emmision – (Edison effect) is the boiling off of electrons(e-)

X-ray production - X rays are produced in a highly evacuated glass bulb, called an X-ray tube, that contains essentially two electrodes—an anode made of platinum, tungsten, or another heavy metal of high melting point, and a cathode. When a high voltage is applied between the electrodes, streams of electrons (cathode rays) are accelerated from the cathode to the anode and produce X rays as they strike the anode(target).

Potential difference - the difference in electrical potential between two electrodes. [and anode(+) and a cathode(-)].

Diode – is an anode(+) and a cathode(-).

Brehmstraluung Radiation – is a type of radiation produced from the deceleration of electrons by hitting a target.

Characteristic Radiation – low level radiation produced when the inner orbit electrons of the target get excited and change energy states.   It is characteristic of the material of the target.