Proton and Heavy Ion Therapy: An overview: January 2017
12
Figure 3
Diagram demonstrating a typical ion-beam facility with two fixed beam treatment rooms (#5), where the
treatment beam enters the room and is targeted at a particular site and one treatment room within a gantry
(#8)
26
The accelerated protons or carbon ions are then directed towards the treatment rooms, with
magnets guiding and focusing the beam within high vacuum ‘beamline’ structures. In the
treatment rooms (position 5, Figure 3), the proton or carbon ion beam enters via a window and is
directed by computer-control to the required treatment site in the patient, who is positioned on a
robotics-based treatment couch. The patient’s position is controlled by a high precision image-
guidance system (position 6, Figure 3), using digital X-rays taken prior to irradiation, to match
those taken at the treatment planning stage to accurately align and adjust the position of the
patient. Different treatment protocols may require the use of a gantry (position 7, Figure 3), which
rotates around the patient to deliver therapy beams toward the patient at the optimal
combination of angles. The patient lies within the gantry (position 8, Figure 3).
26
As one example, Germany’s Heidelberg combined proton and carbon ion-beam facility took five
years to construct at a total cost of €119 (AU$187 million). The facility is 5,027 m
2
and three
stories high (two of which are underground) to accommodate the size of the rotating gantry. The
facility has three sections: above-ground glass structure with the staff offices; underground
particle therapy area; and the copper block with the heavy ion rotating gantry, which weighs 670
tons and is 13 meters in diameter that extends through all three stories. It is expected that in the
long term this facility will treat up to approximately 10 per cent of cancer patients whose tumour
growth cannot be readily controlled with conventional radiation therapy, that is, those patients
with tumours that are located deep in the body; those with tumours that are resistant to
conventional radiation; and those with tumours that are surrounded by radiation-sensitive healthy
tissue, such as the optic nerve, brain stem, spinal cord or the intestines.
26
Proton and Heavy Ion Therapy: An overview: January 2017
13
Since this facility started operating in November 2009, over 1,000 patients have received particle
therapy in the two horizontal irradiation sites. Once the gantry, commissioned in late 2012, is
running at full capacity, it is estimated 750 patients will be treated per year. The facility operates
24-hours a day, with the particle beam used around the clock, either for therapeutic or for
research purposes. It is used for patient radiation six days a week for an estimated 12 to 14 hours
a day. The accelerators are also in use 24 hours a day and are operated in shifts. The entire facility
consumes a maximum of three megawatts, equivalent to the energy required for a small town
with a population of approximately 3,000 people.
26
However, it should be noted that
developments in technology over the relatively few years since this system was installed,
particularly in gantry design and superconducting magnets, has significantly reduced the size and
weight of gantries. Japan’s National Institute of Radiological Sciences (NIRS) Heavy Ion Medical
Accelerator in Chiba (HIMAC) recently installed a smaller and lighter superconducting magnet
gantry for carbon ions that weighs less than half the weight of the Heidelberg gantry. A second
superconducting gantry is also currently planned for installation at Yamagata University.
Additionally, there are particle therapy systems in development utilising alternative acceleration
technologies. Laser-driven proton accelerators have been proposed which have potential to
reduce equipment costs to a fraction of current accelerators;
27, 28
however this approach is still
theoretical with challenges in controlled beam production, efficient beam guidance, and radiation
protection.
27, 29
Advanced Oncotherapy (London, United Kingdom) is developing a series of cavity LINAC modules,
which are anticipated to be able to accelerate protons to therapeutic speeds. There are claims that
this system, planned for commercialisation in 2017, will vastly reduce facility costs through savings
in space, equipment, shielding, maintenance and operating costs.
30, 31
However, at present, this
technology is unproven.
Figure 4
Advanced Oncotherapy LINAC Image-Guided Hadron Technology (under development)
32
Proton and Heavy Ion Therapy: An overview: January 2017
14
Furthermore, Ion Beam Applications (IBA, Belgium) and the Joint Institute for Nuclear Research
(JINR, Dubna, Russia) are developing a cyclotron with superconducting coils that can produce 400
MeV energy, allowing for acceleration of both protons and carbon ions.
24
This hybrid system is yet
to be demonstrated, however may offer a compact and cost-effective solution for particle therapy.
Particle Therapy Facility Costs
It is well recognised that high equipment and facility costs, with long construction times, are a
major obstacle in the adoption of particle therapy.
1
Although costs are decreasing with the
introduction
of newer compact designs, a particle therapy facility represents a significant
investment, with costs directly relating to facility size. Publicly reported PBT facility costs range
from approximately $34 million for a compact, single-room facility to approximately $260 million
for a larger, e.g. five-room facility; and up to approximately AU$290 million for a heavy ion facility
(see Appendix A and B).
Although particle therapy installation costs are be considered high, it should be recognised that
particle accelerators and treatment gantries have an intended lifespan of 30 years,
33, 34
compared
to 10 years for linear accelerators utilised in conventional radiotherapy.
35
Therefore, direct
comparison of initial construction costs may be misleading, as linear accelerators may require
multiple replacements over the typical lifetime of a particle accelerator.
Additionally, proton therapy facilities have high annual maintenance and service costs, which are
reported as approximately one-tenth of the purchase price.
1
Further additional annual costs would
include medical personnel and staff involved in service delivery, associated equipment (medical
imaging and treatment planning facilities), administration and running costs (e.g. energy).
If an Australian particle therapy facility were to be established, there will be a requirement for
formal particle therapy training and credentialing for radiation oncologists, medical physicists and
radiation therapists, which should be undertaken by relevant Australasian colleges (e.g. the Royal
Australasian College of Radiologists; RANZCR).
13
This training will likely involve the international
exchange of personnel through fellowships, which will necessitate recognition
of international
credentialing for visiting experts to supply local training.
It is also noted that where patients are required to travel to access such a facility, there will be
travel and accommodation costs incurred.
These high overheads result in particle therapy being more expensive than conventional
radiotherapy treatments. When compared to conventional radiotherapy facilities, a PBT facility
has a reported treatment fraction cost ratio of 3.2, and 4.8 for a combined proton/carbon ion
facility.
36
However, research is emerging that reports PBT may be more cost-effective than
conventional radiotherapy when quality adjusted life years are taken into account in
calculations.
34
A recent systematic review concluded that PBT offers promising cost-effectiveness
for paediatric brain tumours, well-selected breast cancers, advanced non-small cell lung cancer,
and high-risk head/neck cancers. However, cost-effectiveness was not demonstrated for prostate
cancer or early stage non-small cell lung cancer.
37