28-Apr-2019
A one-stop national cancer facility by 2022.
- 24-storey new building will have four times more capacity to serve rising cancer incidence in Singapore
- Patient-centric features to improve patient flow and experience
- Purpose-built to house a new Proton Therapy Centre and research facility for immunotherapy
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| Fig 1 - Minister for Health at the Groundbreaking Ceremony for New NCCS |
With
rising cancer incidence in Singapore, the new NCCS building will be
four times larger than the current centre to meet future needs. Located
on SGH Campus, the new one-stop 24-storey NCCS will house facilities
dedicated to cancer care and rehabilitation, research and education. The
building is targeted to be ready by 2022.
Prof
Soo Khee Chee, Former Clinical Director of NCCS said, “In planning for the new
building, our focus is on providing person-centred care that addresses
all the needs of cancer patients and their family members. We have
learnt from our collective experiences at NCCS and best practices from
renowned cancer centres overseas. The design and layout of the clinics
and waiting areas are all carefully planned to improve workflow and care
coordination. Our priority is to provide our patients with easy access
to the best care possible as we fight cancer together.
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| Fig 2 - An artist impression of the New National Cancer Centre |
Proton beam therapy is a type of radiotherapy that uses a beam of high energy protons, which are small parts of atoms, rather than high energy x-rays (called “photons”) to treat specific types of cancer.
Proton beam therapy enables a dose of high energy protons to be precisely targeted at a tumour, reducing the damage to surrounding healthy tissues and vital organs which is an advantage in certain groups of patients or where the cancer is close to a critical part of the body such as the spinal cord.
Proton therapy cancer treatment begins when each proton
begins its journey at the injector located within an electric field. In the
field, hydrogen atoms then separate into negatively charged electrons and positively
charged protons. The protons travel through a vacuum tube within a
pre-accelerator. This process boosts their energy to two million electron
volts. The protons continue in the vacuum tube and begin their high-speed
journey in the synchrotron. They travel around the synchrotron about 10 million
times per second. Each time they circulate, a radiofrequency cavity within the
ring delivers a boost of energy. This increases the protons' energy to between
70 and 250 million electron volts. The voltage achieved is enough to place them
at any depth within the human body.
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| Fig 3 - Synchrotron and the beam transport system |
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| Fig 4 - Beam Transport System |
After leaving the synchrotron, the protons move through a
beam transport system, continuing in the vacuum tube through a series of
steering and focusing magnets that guide them to the proton treatment rooms.
Each proton treatment room has a beam delivery system, or nozzle, is the last
device the protons travel through before entering the body. The nozzle shapes
and spreads out the proton beam in three dimensions.
Radiation oncologists must determine location, shape, and
tissue density of the target tumor before determining the number of protons to
deliver. They must also calculate the depth that the protons must travel in
order to calculate the speed and shape of the beam. These decisions render a
beam that is highly accurate and practically ‘tailor made’ for a specific
treatments.
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| Fig 5 - Proton Therapy Room Gantry |
After leaving the nozzle, the protons enter the patient's
body.
The equipment in the proton therapy treatment rooms vary
based on the conditions treated. One proton treatment room may have a
stationary beam with two branches – one branch for irradiating eye tumors and
the other for central nervous system tumors and tumors of the head and neck.
The other treatment rooms may have gantries – wheels that are 35 feet in diameter
that revolve around the patient to direct the beam exactly where needed. From
the patient's perspective, all that is visible is a revolving, cone-shaped
device.
Proton beam therapy is only suitable for certain types of cancer, such as
highly complex brain, head and neck cancers and sarcomas as it does not lead to
better outcomes for many cancer cases than using high energy x-rays, which is
still considered the most appropriate and effective treatment for the majority
of cancers.Like high energy x-ray radiotherapy, proton beam therapy is painless, but patients may experience side effects similar to those experienced from other forms of radiotherapy.
How
Does Proton Therapy's Effectiveness Compare to IMRT or Other X-ray Treatments?
Because proton beams can be delivered in higher doses and
with far more accuracy, proton therapy typically can control cancer with fewer
treatments than IMRT. This pinpoint accuracy also results in fewer long-term
side effects (since the radiation does not spill over and damage healthy tissue
and organs) meaning that patients treated with proton therapy experience a
higher post-treatment quality of life as compared to IMRT and even conventional
x-ray treatments.
Is
Proton Radiation Therapy Ever Combined?
Yes. Conformal proton therapy is often used in conjunction with X-ray
therapy. This method boosts the dose to sites of gross disease and allows
irradiation of a large tissue volume. Depending on the amount of cancer within
a particular lymph node and type of cancer that is present, a patient may be at
risk for harboring microscopic nests of cancer cells within the nodes. These
nodes may lie at some distance from the primary tumor and may not be irradiated
if conformal proton treatment alone is delivered to the tumor.The objective of the treatment plan is to treat both the primary tumor and any areas where a microscopic tumor might hide. X-ray treatment alone will limit the total dose of radiation that can be given due to the high doses it delivers to large amounts of healthy tissue. Therefore, conformal proton radiation therapy is used to treat the primary tumor, and is then followed by X-ray therapy to treat the regional nodes. By giving some of the treatment with conformal protons, the total X-ray dose can be reduced substantially.
This reduces the risk of complications and permits treatment of potentially involved lymph nodes. Microscopic cancer within these nodes might be missed if X-rays were not used.
Side-Effect
Since proton therapy allows the radiation to unfold directly
in the tumour, the surrounding tissue and organs are protected to the best of
their ability. If a reaction – i. e. a side effect – occurs, only the
irradiated body region is usually affected. This can lead to irritation of the
skin or mucous membranes, which usually recede completely within two to three
weeks after treatment. Sometimes, however, a kind of permanent scarring can
also occur as a late consequence.
Reference: https://protons.com/proton-advantage/how-does-proton-therapy-work
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