Zap! Pfffft! Mind the Bubbles

A highlight of Mary and my recent trip to London was a visit to the Institute of Cancer Research where son-in-law Hugh Morris is looking for better ways to use ultrasound to kill tumors.  The Institute shares building with a cancer hospital so they are in no danger of having their work become too theoretical.  Cancer sucks and it’s good to be where people are doing something about it.

Ultrasound is both used diagnostically to locate tumors and surgically to attack them without invasive surgery.  To over-simplify, multiple beams of ultrasound converge on a tumor.  None of the individual beams has enough energy to damage the skin and other tissues it is passing through.  But, at the convergence point, pfffft!.  No need for an incision. Little collateral damage.  No general anesthesia.

But, in real life, nothing is quite this simple.  Bubbles form where the heat is high.  These bubbles can both scatter energy back to innocent tissue and block energy from reaching the cancerous cells.  So how to avoid the bubbles?  Avoid building up to critical temperatures.  What are critical temperatures?  How does heat travel through the tissue in the few seconds the beams are being applied?  How do you measure temperature since you don’t want a probe at the point of convergence which would also deflect energy?

These are the issues Hugh is working on with cow livers fresh from the butcher.  He thought we might be put off by the sight and smell of the experiments.  We were fascinated and proud.  BTW, experimenters still keep notebooks full of observations of each experiment even though they have plenty of computers around and in use.

Being around young scientists (I’m old; I’m allowed to age-discriminate) is fun.  One woman wants to know why the cells die when they get zapped.  Not enough to say “of course they die; they were zapped.”  Forensics are helpful in better targeting cancer cells and minimizing dangers to the rest of the body.  Turns out there is almost nothing known (yet) about the exact cause of cell death from this relatively minor heating.

Another scientist asks: “who says bubbles are bad?”  Maybe they can be used to BETTER focus the beam.  He’s experimenting with a second ultrasound source which induces bubbles before the zapper zaps.

As always the toolmakers are in great demand in a lab.  At tea, we met a woman from China who builds the custom hardware and software they need for their experiments.

Hugh set up a discussion with colleague Alex who’s working on ultrasound for treatment of prostate cancer – always interesting to us old guys.  One of the more interesting points was the social consequence of better diagnostic tools.  The more we see, the more scary stuff we see.  First reaction is to operate more often.  But, operations are also risky.  Turns out that a lot of that scary looking stuff is pretty prevalent and may never turn into anything really dangerous.  So what to do?

People don’t like being told “you have a pre-cancerous condition; we’re not going to do anything” even though doing nothing may well be the best course of action.  This course of non-treatment used to be called “watchful waiting” because follow-up surveillance is done.  Bad marketing name.  People hated it.

Now people are much happier with a course of treatment called “active monitoring”.  Same procedures as watchful waiting but it’s much more satisfying to being doing something “active”.  I agree.

And we’re glad Hugh is on the case.

Comments

[Hugh Morris]

Thank you Brian for your best wishes, I'll have a look for that book.

Another large application of therapeutic ultrasound (HIFU in particular) is haemostasis. Use in surgery to stop haemorrhaging being one example of this application. It can also be used to fuse blood vessels feeding a tumor (benigh or cancerous), though this technique is still in the development stage.

To get the most use out of HIFU, I think an interdisciplanary approach is required. For example, HIFU is being used to treat uterine fiberoids but the treatment is made more effective by putting the patient on a course of drugs design to shrink the tumor. Smaller tumors are easier to treat with HIFU.

[bill hillard]

I wonder if anyone is using this technique to treat hemophiliac pseudotumors? Hemophiliacs get non-cancerous tumors, but they are difficult to remove because the operation causes internal bleeding that is difficult to stop. A friend has a hemophiliac pseudotumor that is the size of a volleyball and must take morphine for the constant pain.

If this technique could stop the blood flow to the tumor so that it stops growing, it would be a wonderful application. Unfortunately, due to the small number of hemophiliacs, and the even smaller number with inoperable tumors, little research goes into this topic.

[Brian Dowd]

I am a cancer survivor (testicular) and just returned home last night from the first LIVESTRONG Summit in Austin. I was selected as a delegate along with 800+ other survivors and caregivers from around the country. Our objective for the summit was to identify goals and develop action plans to change the face of cancer and cancer survivorship. We believe we identified numerous areas that need attention, and one of those areas was “break through research”.

This morning I read your post and I could not help but commenting on an inspiring book I read on my flight home last night, “A Call to Action”. This book covered the Prostate Cancer Foundation’s efforts which changed the cancer community forever. I hope Hugh is some how connected to the PCF. It seems Hugh is working on break though testing and I wish him the best.

As a cancer survivor I love to hear such promising news. We need more of the world’s smartest doctors and researchers working on treatments and cures.

[Michael Buckbee]

Interesting about the social aspects of diagnosis. I work with a number of orthopedic surgeons who routinely see spine patients. Their basic rule of thumb is that going solely by MRI/CT/X-Rays you'll detect anomalies in about 30% of the population. The vast majority of those causing no pain, discomfort or even awareness that there is a problem.