1. From Accelerator to Medical Device
Practicalities of Machine Implementation Within the Context of High Gradient Linacs
From Accelerator to Medical Device
John Allen
Chief Engineer - Linacs

2. Today’s cancer care challenges
“I want to understand toxicity curves.”
“I need to maximize machine utilization.”
“I want to reduce patient treatment times.”
“I want to quickly see how a patient’s treatment is progressing.”
“I need to reduce costs.”
“I want to compare plans from multiple sources.”
“I want personalized care.”

3. To treat patients with a linac it needs to be a medical device, not just a working experiment, What does this mean?

4. To make a regulatory submission there are two distinct routes
Predicate device
This is the easier route
Need to substiantiate that your new device is clinically equivalent to an exsisting registered device
You cannot make claims that it is clinically more effective.
In the US this is known as the 510k process, most new devices follow this process (premarketing notification)
Novel device
It you want to claim that your medical device is novel and in some way better than existing devices then, you will need to follow a pre market approval process.
PMA will involve clinical trials which are very complex and costly to run.
In the case of a linac you will also have the problem that you need an investigational device approval before you can try the novel device on real patients.

5. New Medical devices, the ethical challenge
When radiotherapy was initially developed cancer survival rates were very low. Hence it was possible to try novel techniques. Today radiotherapy is mature and in some cases has 5 year survival rate better than 70%., Any proposed new technique must not be a backward step, otherwise it may be considered unethical.
Graphic credit: Cancer Research UK

6. Market drivers Radiotherapy is cost-effective
More empowered and informed patients choosing non-invasive methods
Hospitals investing in revenue- generating equipment and IT systems
Advanced curative techniques increase the use of radiotherapy
New technology will increase averages
Healthcare IT spending growing rapidly
Increase in cancer incidence
Lack of capacity

7. Where might VHEE be positioned?
in relation to other radiotherpy products
Conventional (electron beam linac) radiotherapy
Installed base around 10000
Sale price between $1M and $3M (US$).
Cost price estimated 1/3rd of this figure. (this information is not public)
Built in factories, shiipped to site and quickly installed.
Over 90% of current radiotherapy deleved n such system
Proton Systems
Can cost $100M
It is claimed that these systems are the most expensive medical devices ever deveopled.
Only a tiny number of patients have access to this treatement.
Clinacally proven only for a few specialist indications.
Between the two above products
Estabilishing a “new” modality, this will require hospital to have create business plans around this, e.g reimbersment.

8. Small system built in factories cost less
What common factors drive modern manufacturing?
Large volumes
Easy to ship globally

9. Why would industry invest in a new radiotherapy development
Cost of developing a new radiotherapy system is very high
Upwards of $100M.
Time to market is many years.
Hence return on investment would need to be commercially attractive.
Return will be more attractive if there is less competition in the target segment.
However many new medical equipment are a zero-sum-gains, since they take money from existing budgets.
This may make it unattractive for existing incumbent medtech suppliers.

10. Non financial barriers to entry
Medical Physics is a highly regulated discipline.
The community will need to be convinced that any new modality does not increase risk
Uncertainty in absolute dose calibration
Validation of treatment planning systems
QA protocols that are validated by credible national authorities. (e.g, TG100 from AAPM)
Concern over unknown paths leading to possible mistreatment.
Lack of IEC standards for medical linacs above 50MeV
Understand why “presumed compliance” is significant to reduce commercial risk.

11. Screenshot from XVI:
The green areas show where the patient setup differs from the planning CT
Image guidance
Radiotherpy advances are now dominated by image guidance
Challeges for VHEE, wrt image guidance
MR is not possible?
CT should be OK
In what way will VHEE help with IRGT?
Can VHEE exploit new imaging oppotunities?
CAN VHEE deliver very high dose-rate that enable “flash” delivery?
Freezing motion is one way to manage motion in radiotherapy.
But this requires low latency imaging and close coupling between inaging and delivery.
Reminder:
IGRT allows imaging at the time of treatment. Without it the margins of radiotherapy have to increase to allow for setup uncertainty.

12. Could Flash radiotherapy be VHEE’s usp
A recent paper from the institut Curie may indicate that very high dose-rates might be have a favourable therapeutic ratio.
If combined with motion management this might be a usp.
Avoid the inefficiency of bremsstrahlung inefficiency
Deliver a therapeutic beam in a time much less than the human organ motion.
However there are complex safety and QA requirements

13. Beam collimation MLC or scanned beam? Transverse penumbra?
Questions for VHEE
MLC or scanned beam?
Transverse penumbra?
Treatment planning accuracy
The challenge of “gold beam data”

14. Linac House, Fleming Way, Crawley, UK
John Allen
Linac House, Fleming Way, Crawley, UK