basic radoppharmaceuticals

1. What is Cancer?
Cancer is growth of cells which are out of control. In
this disease, the cells of the body display uncontrolled
growth, invasion and destroys adjacent tissues and
spreads to other body locations.

2. Treatment of Cancer
Cancer may be treated using :
• Chemotherapy (drugs).
• Radiation therapy.
• Surgery.

3. Factors Which Affect the Choice of
Treatment for Cancer
The size of the tumor.
The position of the tumor.

4. Radiation Therapy
External Radiotherapy
Brachytherapy
Radiation therapy uses ionizing radiation to treat cancer i.e. to
destroy cancerous cells.
There are two techniques in radiation therapy that are used to
treat cancer using ionizing radiation:

5. HOW DOES RADIOTHERAPY WORK?
 X-Rays cause ionization to tissues they penetrate.
 Damages molecules and kills cells.
 Specially affects on fast growing cells – cancer cells.

6. Aim of radiotherapy is to destroy the cancer
cells without serious damage to normal cells.

7. Radiotherapy Treatment
Planning
Simulation
Treatment
Every treatment using radiotherapy has to be rigorously
planned. The process consists of three phases:

8. Radiotherapy Treatment Planning
The cancerous tumour has to
be located so that its size and
position can be analysed.
This information can be
obtained from:
•X-rays
•CT scans
•MRI scans
•Ultrasound images

9. Radiotherapy
Simulation
Once the amount of radiation to be given has
been accurately calculated, the patient then
goes to the simulator to determine what
settings are to be selected for the actual
treatment using a linear accelerator.
The settings are determined by taking a
series of x-rays to make sure that the tumour
is in the correct position ready to receive the
ionising radiation.

10. Radiotherapy
Treatment
Irradiation using high
energy gamma rays.
Irradiation using high
energy x-rays.
Cancerous tumours can be treated using radiotherapy as follows:

11. Radiotherapy Treatment
Irradiation Using High Energy Gamma Rays
Gamma rays are emitted from
a cobalt-60 source – a
radioactive form of cobalt.
The cobalt source is kept
within a thick, heavy metal
container.
This container has a slit in it
to allow a narrow beam of
gamma rays to emerge.

12. Radiotherapy Treatment
Irradiation Using High Energy X-rays
The x-rays are generated by a
linear accelerator (linac).
The linac fires high energy
electrons at a metal target and
when the electrons strike the
target, x-rays are produced.
The x-rays produced are shaped
into a narrow beam by movable
metal shutters.

13. Treatment of Cancer
Radiotherapy
The apparatus is arranged so that it can rotate
around the couch on which the patient lies.
This allows the patient to receive radiation from
different directions.
The diseased tissue receives radiation all of the
time but the healthy tissue receives the minimum
amount of radiation possible.
Treatments are given as a series of small doses
because cancerous cells are killed more easily
when they are dividing, and not all cells divide at
the same time – this reduces some of the side
effects which come with radiotherapy.

15. Radiation Therapy
Brachytherapy
This involves placing implants in the
form of seeds, wires or pellets
directly into the tumour.
Such implants may be temporary or
permenant depending on the implant
and the tumour itself.
The benefit of such a method is that
the tumour receives nearly all of the
dose whilst healthy tissue hardly
receives any.

16. Radiation Therapy
Brachytherapy
Uterus
Cervix
Prostate
Intraocular
Skin
Thyroid
Bone
Brachytherapy is used to treat the following cancers:

17. Field shaping
Shielding of vital organs within a radiation field
is one of the major concerns of radiotherapy.
 Shaping fields is not only to protect critical
organs but also to avoid unnecessary irradiation
of the surrounding normal tissue.

18. Three techniques of field shaping
can be identified in radiotherapy
1- Alloy blocks.
2- Independent jaws.
3- Multileaf collimators.

19. Field blocks

20. Field blocks
Cerrobend lung blocks used when MLC’s may not be
able to cover all critical structures

21. Tracing Customization

22. Heavy metal fabrication

23. The custom block is mounted to the linac

24. Independent jaws

25. Multileaf collimators
MLC is ideally used for (IMRT)
MLC is ideally used for (IGRT)

26. Multileaf collimators

27. Multileaf collimators

28. Sensitive
areas such
as the eyes
and spinal
cord must
be avoided.

29. IMRT
Intensity modulated radiotherapy
Leaves open and close to control the amount of
radiation.
Make dose in the target homogenous.
Minimize dose out of the target.

30. IGRT

31. IGRT
image guided
radiotherapy
Moving target
Tumor shrinkage or expansion
Changes in shape of the tumor and surrounding
anatomy