Protons are blowing Rad Onc's boat out the CMS water

[IonsAreOurFuture]

If you have to ask then you can't afford it.

No solid information on the price for this new unit, but it should be significantly less than the $31 million that the University of Utah paid for their 180 degree gantry Mevion system in 2021.

Proton Therapy Opens in Utah

Patients, doctors, scientists, donors, and community members gathered on June 23, 2021 to mark the opening of a major new resource for cancer care in Utah. The Senator Orrin G. Hatch Proton Therapy Center at Huntsman Cancer Institute (HCI) is the first of its kind in the Mountain West and one of...

healthcare.utah.edu

Usually about half of that cost is the system and half is the center to house it. Proton construction usually is at least 2 years - one year to build the center, one year to install the system. If you already have the vault built, and don't need a 2 year construction loan, you are way ahead of the game.

The vault for the traditional Mevion system is about 40 x 40 x 40 feet (3 stories high), while this new one is more like 20 x 20 x 12.

Having it on a single story is a huge savings on excavation and 2nd story crane work. The volume of concrete is also much lower to enclose 4,800 cubic feet than 64,000 cubic feet, literally an order of magnitude.

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[RickyScott]

Seems there will be some limitations from treating pts in the upright position?

 

[Gfunk6]

No solid information on the price for this new unit, but it should be significantly less than the $31 million that the University of Utah paid for their 180 degree gantry Mevion system in 2021.

Proton Therapy Opens in Utah

Patients, doctors, scientists, donors, and community members gathered on June 23, 2021 to mark the opening of a major new resource for cancer care in Utah. The Senator Orrin G. Hatch Proton Therapy Center at Huntsman Cancer Institute (HCI) is the first of its kind in the Mountain West and one of...

healthcare.utah.edu

Usually about half of that cost is the system and half is the center to house it. Proton construction usually is at least 2 years - one year to build the center, one year to install the system. If you already have the vault built, and don't need a 2 year construction loan, you are way ahead of the game.

Just as a frame of reference to everyone, let's assume that the new proton unit with a linac-like footprint costs $20M (includes cost of vault). If you are an aggressive negotiator you can alternatively get a state-of-the-art linac workhorse for $4M (includes cost of vault). Therefore, the only way you can make a profit on protons is high volume and good insurance (e.g. low-risk prostate cancer).

It's not just the up-front capital costs, the price to maintain a proton machine including physics support and power requirements is significantly more than just a linac.

 

[RickyScott]

Just as a frame of reference to everyone, let's assume that the new proton unit with a linac-like footprint costs $20M (includes cost of vault). If you are an aggressive negotiator you can alternatively get a state-of-the-art linac workhorse for $4M (includes cost of vault). Therefore, the only way you can make a profit on protons is high volume and good insurance (e.g. low-risk prostate cancer).

It's not just the up-front capital costs, the price to maintain a proton machine including physics support and power requirements is significantly more than just a linac.

Protons make sense from a halo perspective as they drive pts to large centers that are already leveraging at least 5x cms prices with most insurers. If Stanford brings in just 30 additional imrt prostates to their linacs (which they charge 100k+), then it probably makes sense.

 

[medgator]

Protons make sense from a halo perspective as they drive pts to large centers that are already leveraging at least 5x cms prices with most insurers. If Stanford brings in just 30 additional imrt prostates to their linacs (which they charge 100k+), then it probably makes sense.

Practices did the same thing with CK after the turn of the century. Most weren't CK candidates but the idea was to drive consults through the door for it

 

[IonsAreOurFuture]

Seems there will be some limitations from treating pts in the upright position?

Some limitations with a chair gantry include no vertex beams or couch kicks - axial only - sort of like a Tomotheray, Halcyon, MRI or PET linac, except it's tilted up vertically.

Extremity sarcoma in a mid-thigh is maybe too low. I think for anything below the pelvis the vertical CT scanner might have trouble reaching that low, but those are pretty uncommon. Might be hard to treat inguinal nodes for anal CA without going through a long skin crease or thigh. Vulvar too, no frog leg I bet. I think 90% of scenarios are covered with the chair. I believe Madison, Wisconsin is putting in one of each: a traditional gantry and a chair from Leo, best of both worlds.

The chair can do craniospinal, by raising the seat height to different levels to extend the fields. There are some special advantages to staying upright too, like less choking on secretions, less liver motion = smaller ITVs, and better upright lung inflation = easier to meet V20 constraints.

I haven't seen time studies yet, but I suspect the chair will improve room turnaround time since you don't have to help the patient climb up onto a couch, lay them down, sit them back up, help them off, get their shoes back on. Most people are pretty good at walking, sitting down, and getting back up, unless very frail, but those tend not to be proton candidates anyway. Anyone traveling by ambulance or gurney due to limited performance status or a medical emergency would be on a linac anyway.

 

[RickyScott]

Some limitations with a chair gantry include no vertex beams or couch kicks - axial only - sort of like a Tomotheray, Halcyon, MRI or PET linac, except it's tilted up vertically.

Extremity sarcoma in a mid-thigh is maybe too low. I think for anything below the pelvis the vertical CT scanner might have trouble reaching that low, but those are pretty uncommon. Might be hard to treat inguinal nodes for anal CA without going through a long skin crease or thigh. Vulvar too, no frog leg I bet. I think 90% of scenarios are covered with the chair. I believe Madison, Wisconsin is putting in one of each: a traditional gantry and a chair from Leo, best of both worlds.

The chair can do craniospinal, by raising the seat height to different levels to extend the fields. There are some special advantages to staying upright too, like less choking on secretions, less liver motion = smaller ITVs, and better upright lung inflation = easier to meet V20 constraints.

I haven't seen time studies yet, but I suspect the chair will improve room turnaround time since you don't have to help the patient climb up onto a couch, lay them down, sit them back up, help them off, get their shoes back on. Most people are pretty good at walking, sitting down, and getting back up, unless very frail, but those tend not to be proton candidates anyway. Anyone traveling by ambulance or gurney due to limited performance status or a medical emergency would be on a linac anyway.

How stable is the chair? seems like pt could slouch?

 

[evilbooyaa]

not better survival. slightly better side effect profile. enough to get the private insurer/nccn green light.
skin toxicity maybe worse with protons, swallowing better is going to be my guess. especially if treating ipsilateral only.

this is just a wild as* guess though based upon my review of institutional series and anecdotal cases.

Last time proton folks had sensitive OAR touching PTV posteriorly, like rectum abutting prostate, toxicities seemed to be at best, equal, at worst, inferior, in a patient (not on the computer).

Now that it's base of tongue tumor abutting posterior pharyngeal wall and we think swallowing function will be.... better?

I guess maybe the LNs don't spill out into lower constrictors as much? I just want it compared to REAL contemporary IMRT. Not the folks who just contour parotids and no other OARs.

 

[RickyScott]

Last time proton folks had sensitive OAR touching PTV posteriorly, like rectum abutting prostate, toxicities seemed to be at best, equal, at worst, inferior, in a patient (not on the computer).

Now that it's base of tongue tumor abutting posterior pharyngeal wall and we think swallowing function will be.... better?

I guess maybe the LNs don't spill out into lower constrictors as much? I just want it compared to REAL contemporary IMRT. Not the folks who just contour parotids and no other OARs.

My unilateral oropharynx do great. Almost never get concurrent chemo as well.

 

[evilbooyaa]

My unilateral oropharynx do great. Almost never get concurrent chemo as well.

With protons or photons? My unilateral oropharynx patients do great with just run of the mill IMRT. Nearly anyone getting unilateral H&N RT should do fine besides perhaps skin toxicity at most. And this is even with concurrent chemo...

 

[RickyScott]

With protons or photons? My unilateral oropharynx patients do great with just run of the mill IMRT. Nearly anyone getting unilateral H&N RT should do fine besides perhaps skin toxicity at most. And this is even with concurrent chemo...

Photons, but typically no chemo because if there were muliple nodes justifying chemo, I would treat bl neck.

 

[thecarbonionangle]

Photons, but typically no chemo because if there were muliple nodes justifying chemo, I would treat bl neck.

Thats fine. There are now growing data tho that treating ipsi neck is fine even if multiple ipsi nodes.

 

[IonsAreOurFuture]

Just as a frame of reference to everyone, let's assume that the new proton unit with a linac-like footprint costs $20M (includes cost of vault). If you are an aggressive negotiator you can alternatively get a state-of-the-art linac workhorse for $4M (includes cost of vault). Therefore, the only way you can make a profit on protons is high volume and good insurance (e.g. low-risk prostate cancer).

It's not just the up-front capital costs, the price to maintain a proton machine including physics support and power requirements is significantly more than just a linac.

I think that this compact proton machine is not intended to compete with a Truebeam, but with the larger single room or multi-room proton centers.

A medium sized city with an NCCN center, major university or NCI designation can now offer nearly the same thing that MD Anderson just spent $160 million to put in 4 rooms.

$15 to $20 million is a lot of money, but still represents a much smaller barrier to entry than $40-50 million like UAB's or Beaumont's single room proton center cost just a few years ago. Never having to move dirt or expand a footprint removes a big barrier to adoption, too.

Many academic centers or big community "nonprofits" have a large central hub with 3 or 4 linacs. If one old linac was due to be replaced with an MRI linac or Reflexion machine, applying that $5+ million toward a proton machine leaves only 10 million. A single large donor or 10 smaller investors in a joint venture can probably take care of that.

 

[thecarbonionangle]

To further add: If one wants to be conservative can use HN005 rules when considering ipsi neck treatment. Evidence that it is ok to do ipsi neck even if multiple nodes is growing although not level 1 yet.

Quick search shows this: there are many others

Characterizing Lymph Node Burden With Elective Unilateral Neck Irradiation in Human Papillomavirus-Positive Tonsil Squamous Cell Carcinoma: Defining the Upper Limits

ObjectivesElective unilateral neck irradiation in well-lateralized tonsil carcinoma for N2b disease is controversial. Metrics regarding nodal burden beyond the N-stage to define the upper limit of this de-escalation approach remain limited. We investigated ...

www.ncbi.nlm.nih.gov

If one wants to be conservative, perhaps overly, i would consider ipsi neck treatment when:

1) 1-2 nodes in same nodal level, <3cm
2) “well lateralized”
3) more controversial: <1cm involvement of soft pallate or BOT

 

[deleted1111261]

To further add: If one wants to be conservative can use HN005 rules when considering ipsi neck treatment. Evidence that it is ok to do ipsi neck even if multiple nodes is growing although not level 1 yet.

Quick search shows this: there are many others

Characterizing Lymph Node Burden With Elective Unilateral Neck Irradiation in Human Papillomavirus-Positive Tonsil Squamous Cell Carcinoma: Defining the Upper Limits

ObjectivesElective unilateral neck irradiation in well-lateralized tonsil carcinoma for N2b disease is controversial. Metrics regarding nodal burden beyond the N-stage to define the upper limit of this de-escalation approach remain limited. We investigated ...

www.ncbi.nlm.nih.gov

If one wants to be conservative i would consider ipsi neck treatment when:

1) 1-2 nodes in same nodal level, <3cm
2) “well lateralized”
3) more controversial: <1cm involvement of soft pallate or BOT

For multiple nodes, is there evidence that there is high risk of contra dz?

I thought there were multiple retro studies saying N2b was fine to be treated ipsi?

 

[thecarbonionangle]

For multiple nodes, is there evidence that there is high risk of contra dz?

I thought there were multiple retro studies saying N2b was fine to be treated ipsi?

yes i think that is fine, follow HN005 generally, just saying most conservative take is that. It is clearly an area of “controversy”

 

[evilbooyaa]

Photons, but typically no chemo because if there were muliple nodes justifying chemo, I would treat bl neck.

Not to turn this into a 'when to do ipsi neck' thread (although if that happens I'll spin it off into its own discussion) but my decision to treat ipsi neck is driven by the primary tumor, almost never the bulk of LN disease. And even on that, I am likely more conservative - any BoT or soft palate involvement gets bilateral neck. I know studies have looked at < 1cm extension or 2cm from midline and still offered, it just doesn't make a ton of sense to me.

If old (AJCC 7th edition) N2b or lower, I recommend unilateral neck. If a node is > 6cm in size I would likely have pause. But single node > 3cm or multiple ipsi nodes does not make me think that the retrograde flow will be SO dramatic so as to push disease all the way to the contralateral neck. Maybe I cover IB and/or V if bulky N2b.

 

[TheWallnerus]

Not to turn this into a 'when to do ipsi neck' thread (although if that happens I'll spin it off into its own discussion) but my decision to treat ipsi neck is driven by the primary tumor, almost never the bulk of LN disease. And even on that, I am likely more conservative - any BoT or soft palate involvement gets bilateral neck. I know studies have looked at < 1cm extension or 2cm from midline and still offered, it just doesn't make a ton of sense to me.

If old (AJCC 7th edition) N2b or lower, I recommend unilateral neck. If a node is > 6cm in size I would likely have pause. But single node > 3cm or multiple ipsi nodes does not make me think that the retrograde flow will be SO dramatic so as to push disease all the way to the contralateral neck. Maybe I cover IB and/or V if bulky N2b.

Did you know some people advocate treating bilateral neck in T1 glottic?!

DEFINE_ME

 

[evilbooyaa]

Did you know some people advocate treating bilateral neck in T1 glottic?!

DEFINE_ME

Non-sequitor - it's a Different argument regarding rates of node involvement like DOI for oral tongue cancer (or DOI for vulvar cancer, but I digress) - when glottic cancer DOES spread to LNs, it can spread bilaterally. We know glottic larynx is a midline structure. TBAR for ipsilateral neck - Tonsil, buccal, alveolar ridge, retromolar trigone. Driven by the location of the primary. Not the amount of LN disease (within reason)

 

[TheWallnerus]

Non-sequitor - it's a Different argument regarding rates of node involvement like DOI for oral tongue cancer (or DOI for vulvar cancer, but I digress) - when glottic cancer DOES spread to LNs, it can spread bilaterally. We know glottic larynx is a midline structure. TBAR for ipsilateral neck - Tonsil, buccal, alveolar ridge, retromolar trigone. Driven by the location of the primary. Not the amount of LN disease (within reason)

oh, I disagree that “glottic larynx is a midline structure"... in fact, for early glottic, I almost always code it as non-midline (ie it sits on one side of the midline, doesn't cross the midline, etc)

 

[IonsAreOurFuture]

How stable is the chair? seems like pt could slouch?

I sat in it. There is a knee brace (black board) so your femurs and hips can't slide forward, plus an inflatable belt (think abdominal compression belt) that sits across the waist. The hips and low back will typically be in a vac-lock bag device, so it's a pretty snug sandwich. For the H&N, use a traditional mask. Also can use overhead arm supports for a lung, liver or like a traditional breast board. The back rest can be angled like 15 degrees forward or backward separately from the pedestal. The Leo website has more images. PRODUCTS — Leo Cancer Care

 

[RickyScott]

View attachment 361260

I sat in it. There is a knee brace (black board) so your femurs and hips can't slide forward, plus an inflatable belt (think abdominal compression belt) that sits across the waist. The hips and low back will typically be in a vac-lock bag device, so it's a pretty snug sandwich. For the H&N, use a traditional mask. Also can use overhead arm supports for a lung, liver or like a traditional breast board. The back rest can be angled like 15 degrees forward or backward separately from the pedestal. The Leo website has more images. PRODUCTS — Leo Cancer Care

If price comes down by half in 10 years, this is big threat to varian.

 

[Doctorer]

If price comes down by half in 10 years, this is big threat to varian.

Varian getting out apparently.

 

[grenz]

Varian getting out apparently.

Out of the proton business? That was fast!

 

[BobbyHeenan]

Ignore this data - if you have the right machines proton is still fine.

 

[OTN]

Ignore this data - if you have the right machines proton is still fine.

[citation needed] from Dr. Sameer Keole but I'm not holding my breath

 

[TheWallnerus]

Ignore this data - if you have the right machines proton is still fine.

Couldn’t you just say that about treating doctors too for any given treatment and not just machines

“What sort of doctors performed the treatments that were shown to be inferior? Were they smart, dumb, or just average? This matters!”

 

[thecarbonionangle]

Ignore this data - if you have the right machines proton is still fine.

I believe what Dr. Keole is saying to be absolutely right. Go to a room of ten protonists and ask around regarding CBCT availability, robustness practices, availability of PBS, spot sizes, dosimetry/physics practices and you will be surprised by answers you get even at so called “top” places. There is no grift here, just physics and common sense folks!

Now of course protonists have to put up or shut up. COMPPARE is almost done accruing. Let the data speak with no spin!

 

[RadOncDoc21]

I believe what Dr. Keole is saying to be absolutely right. Go to a room of ten protonists and ask around regarding CBCT availability, robustness practices, availability of PBS, spot sizes, dosimetry/physics practices and you will be surprised by answers you get even at so called “top” places. There is no grift here, just physics and common sense folks!

Now of course protonists have to put up or shut up. COMPPARE is almost done accruing. Let the data speak with no spin!

For some reason I keep getting “protonist” and “penis” confused. Maybe that says something more about me and that I might need therapy.

 

[thecarbonionangle]

For some reason I keep getting “protonist” and “penis” confused. Maybe that says something more about me and that I might need therapy.

Get a therapist with a freudian bent

 

[NotMattSpraker]

I believe what Dr. Keole is saying to be absolutely right. Go to a room of ten protonists and ask around regarding CBCT availability, robustness practices, availability of PBS, spot sizes, dosimetry/physics practices and you will be surprised by answers you get even at so called “top” places. There is no grift here, just physics and common sense folks!

Now of course protonists have to put up or shut up. COMPPARE is almost done accruing. Let the data speak with no spin!

How is this true for prostate? I still don't even understand how protons are better for prostate cancer in theory.

I just want someone to teach me with physics and radiobiological principles and not features.

 

[evilbooyaa]

oh, I disagree that “glottic larynx is a midline structure"... in fact, for early glottic, I almost always code it as non-midline (ie it sits on one side of the midline, doesn't cross the midline, etc)

Aha! I never said that a glottic larynx TUMOR is a midline structure. I meant the entire glottic larynx is a midline structure. One does not, if electing to cover lymph nodes for a glottic larynx case (let's say T3N0 so we can mostly be in agreement) cover just the side that the tumor is on, even if it's very clearly only on the left vocal cord, but causing paralysis of that vocal cord, or growing slightly into the ipsilateral thyroid cartilage.

 

[BobbyHeenan]

I believe what Dr. Keole is saying to be absolutely right. Go to a room of ten protonists and ask around regarding CBCT availability, robustness practices, availability of PBS, spot sizes, dosimetry/physics practices and you will be surprised by answers you get even at so called “top” places. There is no grift here, just physics and common sense folks!

Now of course protonists have to put up or shut up. COMPPARE is almost done accruing. Let the data speak with no spin!

I get it, he's not wrong.

But the default response to all the trials (we've already seen it in the MDA negative stage 3 lung trial is going to be ) - but it was negative because they didn't use X or Y updated proton tech.

I'm probably more of a believer than most on here for protons....but I just don't see proton prostate being clinically superior no matter what fancy tech you're using.

I look forward to the first tweet if Comppare is negative about how with spaceOAR and *insert whatever new upgrade you have* it would have been a positive trial.

 

[TheWallnerus]

Aha! I never said that a glottic larynx TUMOR is a midline structure. I meant the entire glottic larynx is a midline structure. One does not, if electing to cover lymph nodes for a glottic larynx case (let's say T3N0 so we can mostly be in agreement) cover just the side that the tumor is on, even if it's very clearly only on the left vocal cord, but causing paralysis of that vocal cord, or growing slightly into the ipsilateral thyroid cartilage.

If you look at the paper(!) they’re advocating that treating bilateral level 2/3 in early glottic (which includes lateralized T1a) is good. Thank you for pointing out that the larynx is on the right and left side of the body

 

[NotMattSpraker]

I'm probably more of a believer than most on here for protons....but I just don't see proton prostate being clinically superior no matter what fancy tech you're using.

Confession: I'm a huge believer that protons (and carbon) will help some patients a lot. The group is probably small relative to all rad onc patients, and Im worried the business of medicine will ruin it for some of that small group.

Is the primary driver of studying protons in breast and prostate a reasonable scientific hypothesis or something else? I guess Ill never really know.

 

[RadOncDoc21]

Confession: I'm a huge believer that protons (and carbon) will help some patients a lot. The group is probably small relative to all rad onc patients, and Im worried the business of medicine will ruin it for some of that small group.

Is the primary driver of studying protons in breast and prostate a reasonable scientific hypothesis or something else? I guess Ill never really know.

Something else, let’s be real. For most breast and prostate cancers, outcomes are great. What can protons add to these disease sites other then better looking dose clouds that don’t matter clinically. There are definitely situations for protons (re-irradiation, peds) but the race to have the latest and greatest technology to outcompete surrounding centers is excessive and blatantly obvious.

 

[medgator]

Confession: I'm a huge believer that protons (and carbon) will help some patients a lot. The group is probably small relative to all rad onc patients, and Im worried the business of medicine will ruin it for some of that small group.

Is the primary driver of studying protons in breast and prostate a reasonable scientific hypothesis or something else? I guess Ill never really know.

Breast and protons are our bread and butter. No proton center in the US has a profitable pro forma without treating a ****load of prostate.

Peds and retx patients simply won't pay the bills for that technology

 

[Fpg1245]

Something else, let’s be real. For most breast and prostate cancers, outcomes are great. What can protons add to these disease sites other then better looking dose clouds that don’t matter clinically. There are definitely situations for protons (re-irradiation, peds) but the race to have the latest and greatest technology to outcompete surrounding centers is excessive and blatantly obvious.

This is true and it doesn’t seem to matter. They continue to proliferate.

 

[RadOncDoc21]

Get a therapist with a freudian bent

It’s those damn Amazon boxes and Bezos’s spaceship!

 

[Gfunk6]

A simple flowchart to understand proton trials:

 

[TheWallnerus]

A simple flowchart to understand proton trials:

View attachment 361324

Mirror image:

 

[RadOncDoc21]

I think the funniest papers are the consensus countouring ones where they are all over the place with one countour going literally outside the body… yet these are the “experts.”

 

[maxxor]

I think the funniest papers are the consensus countouring ones where they are all over the place with one countour going literally outside the body… yet these are the “experts.”

It would be fun to compare the “experts” with a random radiologist.

 

[TheWallnerus]

It would be fun to compare the “experts” with a random radiologist.

In early days of CT based planning the "experts of rad onc" could not contour a thing without either intense discussion with a random radiologist or asking a random radiologist to sit by their side while contouring

 

[OTN]

In early days of CT based planning the "experts of rad onc" could not contour a thing without either intense discussion with a random radiologist or asking a random radiologist to sit by their side while contouring

Hard to blame them for that, though, as they were having to learn axial anatomy on the fly back then. No excuse now, obviously.

 

[temujim]

In early days of CT based planning the "experts of rad onc" could not contour a thing without either intense discussion with a random radiologist or asking a random radiologist to sit by their side while contouring

continues to this day

 

[Palex80]

… and that the abscopal effect would haven been proven, maybe?

 

[IonsAreOurFuture]

I believe what Dr. Keole is saying to be absolutely right. Go to a room of ten protonists and ask around regarding CBCT availability, robustness practices, availability of PBS, spot sizes, dosimetry/physics practices and you will be surprised by answers you get even at so called “top” places. There is no grift here, just physics and common sense folks!

Now of course protonists have to put up or shut up. COMPPARE is almost done accruing. Let the data speak with no spin!

Loma Linda is the longest operating hospital proton center, 32 years now. If we had a linac (or cobalt machine) from 1990, how comfortable would we be practicing with it now? Would our teams even know how to run or QA it? Would the vendor still support it?

No cone beam, no KV/KV pair, no MLC, no IMRT, SBRT or 3DCRT, no reliable isocenter for radiosurgery, lots of analog dials, cerrobend blocks, 2D only plans, and the record and verify system was a trifold piece of paper filled out by the therapists daily (radiation oncologists were also called therapists not that long ago).

The wedge was an actual wedge of metal that was frequently put in backward or not at all by mistake. The simulator was not a CT, MRI or PETCT, but something called a Ximatron or Odelft and its Xray tube would often overheat while taking films (yes, on actual film) that had to be developed in an onsite dark room.

Contours and field shaping were done in less than 2 minutes with a wax pencil on a light box (I sort of miss that part). The "body contour" was acquired with a piece of wire that you bent to sort of match the patient's skin. The CT of the tumor, if you were lucky enough to have one, was from a tiny 2x2 inch image on an actual piece of film from the radiology dept across the street, that is IF you could find the patient's film jacket. No PACS, no internet, few computers, tiny CRT screens - a 15 inch color monitor was a luxury.

Dose calcs were often hand calcs prescribed to Dmax, d 1/2, or 3 or 5 cm deep. No 3-D dose distribution, maybe "2.5-D" and the patient was assumed to be a uniform block of water, no heterogeneity correction for lung tissue or other cavities. Weekly patient management actually required a lot of medication and coaching to stop patients from quitting due to toxicity. Sometimes I'm surprised that we even survived as a field.

Is it important to inquire about the corresponding technical advances in proton therapy since then?

 

[thesauce]

I have told patients: “Just think of a car from 1990 versus a car from today and you will know why modern linacs are better.”

They still go to Lima Linda. The marketing is just too strong.

 

[TheWallnerus]

Loma Linda is the longest operating hospital proton center, 32 years now. If we had a linac (or cobalt machine) from 1990, how comfortable would we be practicing with it now? Would our teams even know how to run or QA it? Would the vendor still support it?

No cone beam, no KV/KV pair, no MLC, no IMRT, SBRT or 3DCRT, no reliable isocenter for radiosurgery, lots of analog dials, cerrobend blocks, 2D only plans, and the record and verify system was a trifold piece of paper filled out by the therapists daily (radiation oncologists were also called therapists not that long ago).

The wedge was an actual wedge of metal that was frequently put in backward or not at all by mistake. The simulator was not a CT, MRI or PETCT, but something called a Ximatron or Odelft and its Xray tube would often overheat while taking films (yes, on actual film) that had to be developed in an onsite dark room.

Contours and field shaping were done in less than 2 minutes with a wax pencil on a light box (I sort of miss that part). The "body contour" was acquired with a piece of wire that you bent to sort of match the patient's skin. The CT of the tumor, if you were lucky enough to have one, was from a tiny 2x2 inch image on an actual piece of film from the radiology dept across the street, that is IF you could find the patient's film jacket. No PACS, no internet, few computers, tiny CRT screens - a 15 inch color monitor was a luxury.

Dose calcs were often hand calcs prescribed to Dmax, d 1/2, or 3 or 5 cm deep. No 3-D dose distribution, maybe "2.5-D" and the patient was assumed to be a uniform block of water, no heterogeneity correction for lung tissue or other cavities. Weekly patient management actually required a lot of medication and coaching to stop patients from quitting due to toxicity. Sometimes I'm surprised that we even survived as a field.

Is it important to inquire about the corresponding technical advances in proton therapy since then?

All this is true but even so at the time frames specified protons were supposed to be superior to photons. Or else what’s their raison d’etre.

Protons in any time frame are supposed to be superior to photons… I’ve never seen it where (again within a present timeframe of reference) people are like “you know these protons are very limited… we need to wait for some technical innovations before they’re superior to photons and we use them on people.”

It’s the Bragg peak, stupid. Or is it the Bragg peak plus PACS and image guidance.