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Proton therapy for pancreatic cancer, Immobilisation Devices, IMG…
Proton therapy for pancreatic cancer
Beam Arrangement
Spot scanning
: This technique uses a narrow beam of protons that scans the target volume in three dimensions. It allows for more conformal and homogeneous dose distribution than passively scattered protons. It also reduces the dose to the nearby organs at risk.
Double scattering
: This technique uses a combination of scatterers and collimators to spread the beam and shape it to match the target volume. It is less conformal than spot scanning, but simpler and faster to deliver.
Field-in-field
: This technique uses multiple proton fields with different weights and shapes to cover the target volume and spare the organs at risk. It can be used to deliver a simultaneous integrated boost to the gross tumor volume.
Single field or multiple field optimization
: This technique optimizes the dose distribution for each proton field individually or collectively. It can be used to reduce the interplay effect between tumor motion and beam delivery.
Target Delineation
GTV:
Gross lesions and metastatic lymph nodes determined by results from simulation CT, MRI, PET-CT, and diagnostic CT
CTV:
Defined as the GTV including oedema
PTV:
Low-risk PTV was delineated by adding 5mm margin from the CTV, High-risk PTV includes 3mm margin of the CTV to remove the planning organ-at-risk volume
Prescribed Dose
25 GyE in 5 daily fractions for neoadjuvant chemoradiotherapy for resectable pancreatic cancer
50 Gy and a boost of 20 Gy for inoperable pancreatic cancer
67.5 GyE in 25 fractions for definitive chemoradiotherapy for locally advanced pancreatic cancer
50.4–59.4 Gy for adjuvant chemoradiotherapy for resected pancreatic cancer
Advantages vs disadvantages
Disadvantages
Higher Costs
: Installation and maintenance costs are generally higher compared to photon radiotherapy.
Limited Availability
: Proton therapy facilities are not as widespread globally.
Advantages
Precise Targetting
: Proton radiation therapy allows high-dose radiation to precisely target to the tumor or resection bed while protecting adjacent vital organs.
Lower Risk of Secondary Cancers
: Potentially reduces the risk of developing secondary cancers.
Reduced Side Effects
: Lower impact on adjacent healthy tissues results in fewer side effects.
Treatment machine
synchrotron
The synchrotron is a ring in which particles are injected from a pre-accelerator, and then stored and accelerated to a desired energy. Once this energy has been reached, the particles are slowly extracted and sent to a treatment room.
cyclotron
A cyclotron accelerates particles to a fixed energy based on its design. After acceleration, particles move to a degrader (typically graphite) to slow down to the desired energy. The process involves a collimation system and magnetic analyzer to select the beam's energy and spread for transport to the treatment room.
DELIVERY TECHNIQUES
passive scattering technique
spot scanning techniques
(also often called pencil beam scanning)
Manufacturers
Varian Medical Systems
ProTom International
Hitachi
Patient Positioning
Patient in supine position
Group Members:
Ng Zhi Kang (A187777)
Ao Liu (A185439)
Nurul Izyani binti Asri (A189583)
Fatin Rasyidah binti Mohd Khairur Rijal (A188935)
Immobilisation Devices
Head Rest
Wing Board
Arm rest
T-Bar
Arms above head
