The document discusses the linear accelerator (linac), the primary device used for external beam radiation therapy to treat cancer by delivering high-energy x-rays to tumors while sparing surrounding healthy tissue. It outlines the working principle of linac, including components like the electron gun, accelerator guide, and gantry, which work together to shape and direct the radiation beam. Additionally, it describes the operational modes of linac, specifically photon and electron modes, used based on the configuration and models of the device.

1. LINAC (LINEAR
ACCELERATOR)
SIR SYED UNIVERSITY OF ENGINEERING AND
TECHNOLOGY
SYED HAMMAD
AKHTER
2012-BM-071
PRESENTED TO
ENGR. FAHAD
AKBER

2.  Early radiation therapy machines used
a radioactive source like cobalt to produce
the ionizing radiation needed to treat
cancerous tissue. Some machines still use
an active radiation source. But most
radiation therapy today is done with a
linear accelerator.
 The linear accelerator is used to treat all
parts/organs of the body.
 It delivers high-energy x-rays to the
region of the patient's tumor.
 These x-ray treatments can be
designed in such a way that they destroy
the cancer cells while sparing the
surrounding normal tissue.
A linear accelerator (LINAC) is the device most commonly used for external beam
radiation treatments for patients with cancer.
LINAC

3. LINAC (schematic diagram)

4. WORKING PRINCIPLE
•This uses microwave technology to accelerate electrons in
a part of the accelerator called the "wave guide,“.
•Collide with a heavy metal target to produce high-energy x-
rays.
•These high energy x-rays are shaped as they exit the
machine to conform to the shape of the patient's tumor and
the customized beam is directed to the patient's tumor.
•The beam may be shaped either by blocks that are placed
in the head of the machine or by a multi-leaf collimator that
is incorporated into the head of the machine.
•Patient lies on a moveable treatment couch and lasers are
used to make sure the patient is in the proper position.
•The beam comes out of a part of the accelerator called
a gantry, which can be rotated around the patient.
• Radiation can be delivered to the tumor from any angle by
rotating the gantry and moving the treatment couch.

5. Essential accelerator parts
a.Electron Gun: Responsible for producing electrons
and injecting them into the accelerator structure .
b. Accelerator Guide : It generates speed for electrons.
c. Bending Magnet envelope: Electrons are filtered
according to their energy and bend right angle to strike
target
d. Collimator : beam is collimated in head by multi-
segmented collimeter.
e. RF power source : Rf wave is send by source which
is used accelerate electrone in wave guide
Components
.
GANTRY : provide edge to the system and rotate
around body
•RF source
•Modulator
•Accelerating waveguide
OPEARATING CONSOLE :
TREATMENT COUCH : the area on which Patients
are positioned to receive their radiation treatment.

6. LINACs are used primarily to treat
bone cancer and tumors of the head
and neck.
High energy LINACs are used to
treat deep tumors of the pelvis and
thorax.
APPLICATION:
OPERATING MODES
PHOTON MODE
The photon mode use two energies
between 4-23 mw
ELECTRON MODE
The electron mode uses 6 energies
from 5-21 Mw . These mode depends
on config and models of LINAC