Brachytherapy involves placing radioactive sources inside or next to the tumor to deliver internal radiotherapy. It has advantages like high tumor dose and sparing of normal tissues. There are different types depending on implant duration, source position, loading pattern, and dose rate. Permanent brachytherapy leaves radioactive seeds permanently in the tumor, while temporary brachytherapy removes sources after treatment. Interstitial brachytherapy places sources directly in tissue, while intraluminal brachytherapy inserts sources in body lumens. Remote afterloading automates source insertion compared to manual afterloading.

1. Brachytherapy
DR/Saeed Albehairy
Lecturer of clinical oncology, BNS University, Egypt
MD of clinical oncology, Cairo University

2. Definition
• Giving radiotherapy
1- from short distance
2- using radioactive sources
It is also named internal radiotherapy

3. Advantages of brachytherapy
1. High dose of radiation is delivered to tumor in
short time, So biologically very effective
2. Normal tissue spared due to rapid dose fall off
3. Better tumor control
4. Radiation morbidity minimal
5. Radiation reactions localized &manageable
6. Treatment time short – reduces risk of tumor
repopulation
7. Therapeutic ratio high

4. Disadvantages of brachytherapy
1) Invasive
2) Need anesthesia
3) Limited availability
4) Any small error leads to high normal tissue
dose and treatment failure
5) Radiation hazards exposure

5. Types of brachytherapy
Depends on
1. Duration of implant
2. Source position
3. Source loading pattern
4. Dose rate

6. Duration of implant
• Temporary- Dose is delivered over a short period of
time and the sources are removed after the prescribed
dose has been reached. It may be LDR or HDR. The
specific treatment duration will depend on many
different factors, including the required rate of dose
delivery and the type, size and location of the cancer.
Ex :- Cs(Cesium)137, Ir(Iridium)192
• Permanent- also known as seed implantation, involves
placing small LDR radioactive seeds (about the size of a
grain of rice) in the tumor or treatment site and leaving
them there permanently to gradually decay.
Ex :- I(Iodine)125 ,Pd(Pallidium)103, Au(Gold)198

7. Source position
 Interstitial - the sources are placed directly in the target tissue of
the affected site, such as the prostate or breast.
 Contact - involves placement of the radiation source in a space
next to the target tissue.
1. Intracavitary – Consists of positioning applicators bearing
radioactive sources into the body cavity in close proximity to
target tissue eg :- Cervix
2. Intraluminal – Consists of inserting single line source into a body
lumen to treat its surface &adjacent tissue. Eg. esophagus
3. Surface (Mould therapy) Consists of an applicator containing
array of radioactive sources designed to deliver a uniform dose
distribution to skin/mucosal surface.
4. Intravascular – Inserting a single line source to Blood vessels to
treat the layers of blood vessel

8. Source loading pattern
A. Pre-loading :- Inserting needles/tubes
containing radioactive material directly into the
tumor
B. After-loading :- First, the non-radioactive tubes
inserted into tumor
1. Manual After Loading :- Ir192 wires, sources
manipulated into applicator by means of forceps
& hand-held tools
2. Remote After Loading :- consists of
pneumatically or motor-driven source transport
system

9. Dose rate
1. Low-dose rate(LDR)- Emit radiation at a rate of 0.4–2
Gy/hour.
2. Medium-dose rate (MDR)- characterized by a medium
rate of dose delivery, ranging between 2-12 Gy/hour.
3. High-dose rate (HDR)-when the rate of dose delivery
exceeds 12 Gy/h.
4. Pulsed-dose rate (PDR) - involves short pulses of
radiation, typically once an hour, to simulate the
overall rate and effectiveness of LDR treatment.
5. Ultra low dose rate - Dose range 0.03 to 0.3 Gy/Hr

10. HDR V/S LDR
Advantages :-
1. Radiation protection
2. Allows shorter treatments times
3. HDR sources are of smaller diameter than the cesium sources
that are used for intracavitary LDR ,hence reduced need of
Anaesthesia
4. HDR makes treatment dose distribution optimization possible
Disadvantage
1. Radiobiological
2. Limited experience
3. The economic disadvantage
4. Greater potential risks

11. IDEAL ISOTOPE
1. Easily available & Cost effective
2. Gamma ray energy high enough to avoid increased
energy deposition in bone & low enough to minimise
radiation protection requirements
3. Preferably monoenergetic: Optimum 300 KeV to 400
KeV(max=600 kev)
4. Half life:
– Moderate (few years) half life removable implants
– Shorter half life for permanent implants

12. Interstitial permanent implant for prostate

13. Interstitial temporary
breast implant Intraluminal esophageal
brachytherapy

14. Remote Afterloading machine
Manual Afterloading