Basics on PBT
What type of RT is proton therapy?
External beam RT
Other than adults, who would benefit from PBT?
Proton Therapy is also used for administering treatment to children because it decreases the chance of harming healthy, developing tissues.
What are some challenges regarding PBT?
High costs, not enough strong clinical trial evidence, side effects, can not be used for all cancers
How long are most photon treatments delivered?
Delivered over a fractionated course of therapy up to 7 weeks long
Why is proton beam therapy different than photon beam therapy?
Proton therapy reduces the dose to surrounding healthy tissue, beams do not continue passing through the target tissue
What are some possible side effect of PBT?
Fatigue, hair loss around the part of your body being treated, skin redness around the part of your body being treated, soreness around the part of your body being treated
What other therapies can be used in conjunction with PBT?
X-ray radiation therapy, surgery, chemotherapy, or immunotherapy
Advantages of PBT
Protons do not scatter as much as electrons
Treatment is painless
Less Radiation Damage to Healthy Tissues (up to 60% less radiation)
Less side effects compared to traditional radiation treatment 4
Proton beam therapy (PBT) is likely to have reduced risks of late toxicity and secondary cancer
Why can't you use PBT for all kinds of cancers?
Only used for sensitive areas where other treatments would cause damage to surrounding cells, and for tumours that have not spread
What cancer sites is PBT useful for?
Brain and Spinal Cord (Nasopharyngeal Cancers)
Eye (Retinoblastoma and Orbital Rhabdomyosarcoma)
Central Nervous System (Chondrosarcoma and Malignant Meningioma)
Breast
Esophageal
Liver
Lung
What types of tumours is PBT useful for?
Proton Therapy is useful for treating tumours that have not spread, or are near important body structures and organs.
Synchrotron
Protons are injected and circulated in a vacuum tube ring by the action of magnets located along the circular path of the beam. The strength of the magnetic field and RF increases in synchrony along the path with the increase in beam energy.
When the proton beam reaches the desired energy, the protons are extracted
How does PBT work?
When the protons (heavily charged particles) are brought to high energy, they target tumour cells and damage their DNA. Cyclic accelerators will accelerate protons, and the high-energy protons shed some of the energy they carry as they pass through tissue. The protons then deposit the majority at the end of their range, precisely within the tumour target.
Cyclotron
Particles are accelerated along a spiral trajectory guided inside two half-cylindrical electrodes by a uniform magnetic field. An RF pulse is applied, and the charged particles cross the gap and accelerate. Particles reach the deflection plate and hit a target.
This machine is capable of producing a proton beam