Don't Mention the War

Last year the Danish government announced that it will finance a national particle therapy facility together with some private funding agencies. Two applications were submitted for evaluation:

• The Proposal for a Proton Therapy Center at Rigshospitalet (located in Copenhagen)
• The Danish National Center for Particle Radiotherapy (located in Aarhus)

and of course there is a strong interest from each side to host this project. Naturally, since I am part of the Aarhus Particle Therapy Group, I will right out admit I am naturally in favour of our project in Aarhus.

The plan is now that an international expert commission is being setup by the ministry of health. That commission will then evaluate those two applications and give a suggestion where to place such a facility.

If you compare those two applications, you will see that they both apply for a 3-gantry treatment facility. Copenhagen lock themselves on a cyclotron solution, where we in Aarhus are also open to a synchrotron based solution.

Basically the differences can be summarized here:

Copenhagen	Aarhus
3 treatment rooms with 2 gantries	3 treatment rooms with 2 gantries, +1 research room
3rd gantry will be installed later	3rd gantry will be installed later, a fourth treatment room with gantry can be added
Protons	Protons
Cyclotron	Cyclotron or Synchrotron
1000 patients per year	1000 patients per year

So basically what we apply for is rather similar.

What about the costs? If you compare those budgets, you will note that the prices of the equipment and the building are comparable too.

	Copenhagen	Aarhus
Equipment	450 mio. DKK	475 mio. DKK
Building	382 mio. DKK	295 mio. DKK
Supply systems and lines	195 mio. DKK	(incl. in building)
Purchase and demolition of Rockefeller Building	147 mio. DKK	(none)
Total	1174 mio. DKK	770 mio. DKK
Optional 3rd gantry	(not mentioned)	75 mio. DKK

Copenhagen need to build in the middle of the city, whereas we in Aarhus have a pristine green field adjacent to the New University Hospital. This means that the expenses for the Copenhagen proposal are significantly higher than the Aarhus solution, since a building has to be demolished first (they have simply a lack of space in Copenhagen). The "supply lines" cover, as far as I heard, establishing extra power for the facility, please correct me if I am wrong here. The annual operational costs are also similar.

There has been a few articles in the Danish press about the two applications. None of the Journalists managed to actually compare the two budgets, so basically the message was that Aarhus offeres particle therapy at dumping prices. Yeah right.

In addition, I hear a lot of weird arguments, e.g. such a facility MUST be build in Copenhagen, since it is the capital city, and it has a proximity to the airport.

Huh?

How many of the existing facilities are located in capital cities? Lets pick some of the most famous ones: HIT is in Heidelberg (147.000 inhabitants, 1hours drive to next airport). PSI is in Villingen. The Swedish facility is built in Uppsala, and not Stockholm. Why is that so? These research institutions simply had the longest track record in terms of particle therapy! I don't get the point of the closeness of an airport either, since you can reach any point within a few hours in DK by car, and sorry guys... particle therapy is not that acute.

Now, today this conflict took a very curious turn, as Copenhagen announced in Dagens Medicin that they will cut the price 75 % (login required to view link). What is going on?
It seems that Copenhagen suddenly decided to go for a single gantry facility by Mevion, formerly known as StillRiver. To me this looks like a very poor decision. The Mevion facility has been controversial for a long list of reasons. In a scientific article by Schippers and Lomax they list some of the issues with this facility:

• the very compact design of the cyclotron, may lead to large beam losses and resulting activation. 
• repetition frequency of synchrocyclotrons are typically 1kHz which limits applicability of the different pencil beam scanning methods.
• There is no beam analysis and no magnets in the beam path, in other words an energy selection system is missing. This means that the beam will have a poor distal edge, always looking as if it traversed 25-30 cm of material, e.g. when treating head an neck cancers. This limits possible treatment planning techniques, such as patch fields.
• Neutron contamination may be an issue, due to the proximity of the degrader, modulator and collimator(s). 

To this, I might add that the construction of the prototype is still awaiting FDA approval, and we have not seen any data on how this machine operates. We are just in the middle of a never ending scandal about a couple of diesel IC4 trains ordered from AnsaldoBreda a decade ago, where the trains still are not functional and with a significant risk that they never will be. Billions of taxpayer money are lost here. Most Danes are therefore allergic to order unproven technology abroad.

Update: Mevion just got their FDA approval.

Another update: it's a "Premarket Notification" and not a "New Device Approval". Read it here. Thanks to Klaus Seiersen for pointing this out.

The recent article in Dagens Medicin does not even mention that cutting 75% of the price leads to a single-gantry facility, which means the patient numbers needs to be adjusted down, perhaps by 2/3rds.

Finally, if you need three treatment rooms, then measured in costs per treatment room, a conventional solution is cheaper than the Mevion solution, according to Schippers.

I am very astonished, it seems that Copenhagen just scored an own goal. However, I fear this may delay the decision process even more. In the end this is about patients, and if the money is there, we should not be satisfied with giving our patients the most inferior kind of proton therapy, and rely on unproven technology.

Visit at the Primary Standards Laboratory in Slovakia

This post is not related to computing, but more to medical physics. Primary standards dosimetry laboratories (PSDL) are important for medical physicists, since they define fundamental quantities such as dose. If you buy some dosimeter, say, an ionization chamber, it is most likely calibrated at a PSDL (for ample amounts of money) or a secondary standards dosimetry laboratory (SSDL) which is linked towards a PSDL. Not all countries have a PSDL or SSDL, and some countries (like Slovakia in this case) have both PSDL and a SSDL facilities. To my knowledge, Denmark quite recently got the SSDL status at the National Institute for Radioprotection.

During summer vacation 2011, after finishing the run at CERN, I had a rather messy tour across Europe and also went to Bratislava to visit some friends. Here I got the chance to get a tour of the Slovakian PSDL at the Metrological (not to mistaken with the Meteological) Institute. It is my second vist at a PSDL - a few years ago, I visited the PSDL at the National Physical Laboratory in the UK, but I only got crappy mobile phone pictures.

The Metrological Institute of Slovakia, Bratislava.

The director of the institute, Jozef Dobrovodsky gave me a tour of the facility. They have a close cooperation with the NPL - most physicists working with particle therapy may have heard of proton dosimetry expert Hugo Palmans who works at NPL near London, but (quite conveniently) actually lives in Bratislava.

Jozef and Hugo looking at Roos plane parallel ionization chambers from PTW, well suited for measuring depth-dose curves of pencil shaped ion beams.

Outline of the facility.

The facility has a Betatron, a Cobalt-60 unit, a 320 kV X-ray unit, a Caesium-137 irradiator and a neutron vault with various neutron sources.

Mock-up models of Cs-137 sources (these are NOT radioactive).

A part of the control room, with the very well known UNIDOS electrometer by PTW, which I worked a lot with e.g. while at CERN.

Probably the most important room is where the Co-60 irradiator is kept. Co-60 has a long history serving as reference radiation for a wide range of dosimetric tasks. Beam quality is usualy expressed relative to Co-60 standard. However, Co-60 irradiators are getting rare. Radiation treatment with Co-60 is rather something seen in developing countries, at most hospitals they were replaced with megavolt linear accelertors, also for safety issues. (Messing with radioactive sources is always a bad thing and should be avoided). As a researcher, it gets increasingly difficult to get access to a proper reference radiation.

The yellow box holds the Co-60 source, behind the tank an additional collimator is visible which can be mounted in front of the Co-60 unit.

Co-60 irradiation room. The tank holds a Markus ionization chamber, and the dose-rate can be reduced by increasing the distance to the Co-60 irradiation unit.

Next we took a look at the X-ray irradiation room. X-rays have lower energies than Co-60 and are made electrically and not from a radioactive source.

Two X-ray sources are seen here, one in the background with wheels of various copper filers which can be positioned in the beam. Copper filters can remove characteristic lines of the X-ray spectrum, thereby flattening it. In front an X-ray diagnostic device is visible.

How to make 90 Volts. :)

Cs-137 provide a photon field at about half the energy of the MeV Co-60 photons.

Cs-137 irradiation room.

Cs-137 irradiator seen from the front. Aperture can slide to the right, exposing the room to the source.

A real gem was their Betatron: it's a Czech construction, which can deliver both electron and photon beams. The betatron is an old design originally invented by the Norwegian Widerøe, who also invented the idea of drift tubes, widely used at almost any accelerator today. Betatrons (especially functioning betatrons) are a very rare sight today,  most were replaced with LINACs long time ago. I once saw a betatron at the physics department of Freiburg in Germany, but it was not operational anymore. This one however is still functioning! (Look how clean and tidy it is... I am used to messy laboratories.)

Second time I ever see a betatron. Yay! :-)

You can extract either photons or electrons on either side. This is the photon exit (I think).

They even had a spare betatron tube, heavily tarnished by radiation damage to the glass.

Control console for the betatron. Nice and sleek.

Power supply and controls for the betatron. Many components are still genuine Czech, manufactured by TESLA.

Finally we visited the neutron vault. Here they had three neutron irradiators: two different accelerator based sources and a range of radioactive neutron emitters. The neutron sources were kept in a cave in the floor shielded with lots of plastic material for neutron moderation/absorption. The sources they have are quite common. Some intense alpha source (Plutonium or Americium) mixed with some light material (Beryllium). A Californium source was also there which fissions spontaneously.

Neutron vault. In the floor several neutron sources are kept, and can be raised out of the cave by the visible holder. I was a bit hesitant, when the scientist suddenly pulled a string, and the holder surfaced out of the neutron cave, as shown on this picture. “Is it empty?!” “Sure it's empty.”

This accelerator was very cute: protons accelerated towards a tritium target produces a neutron beam. The design of the high voltage terminal looks very much like the design found in the terminal of our Van de Graaf KN machine in Aarhus.

The ion source can be seen in the middle.

Beam is directed against a tritium metal hydride target, which is rotated to redistribute the dissipated power over a larger area. This produces a neutron beam, exiting to the lower left.

I always found acceletor technology very interesting, especially old designs where you easily can recognize what is going on (or not). If it is eastern-european design, it's just even more interesting, since they tend to look rather different and often show signs of various improvisations.

This is some Russian accelerator based neutron source. However, it was not really used if I remember correctly, and unfortunately I didn't pick up all the details about it.

I was once told that its very characteristic for Russian accelerator systems, that the vacuum tubes are fixed with 4 screws only.

This concludes our little tour at the irradiation facilities of the primary standard lab in Bratislava. Thanks to Hugo Palmans and Jozef Dobrovodsky for the tour!

An antiproton and a proton dosimetry researcher meet. No annihilation, but some sort of a bound state, clearly sharing common goals and interests.