Ultrasound Phantoms: War were declared

The ultrasound phantoms work.  They have a few limitations, but for certain applications, these cheap DIY phantoms are going to be far superior to expensive commercial phantoms.  In fact, part of their DIY nature makes them inherently superior.  Creating a phantom for a special purpose, such as vessel cannulation, foreign body identification, or needle procedures, is simple.

One of the big issues that has come up is bacterial/fungal growth on the phantom.  This should be expected, as the phantom is constructed of gelatin and sugar-free psyllium.  The system is essentially a giant petri dish.  I needed to find a way to inhibit microbial growth.  Not just inhibit, but stop.  Completely and totally.

I lucked out in a couple of ways.  I tried mixing some bleach into the material when it was on the stovetop.  The mixture foamed up a fair amount.  This wasn't a big issue with the first two layers, as pouring the next layer seemed to dissolve the previously settled foam.  The final layer settled with a very large amount of foam.  This foam is a random mixture of air and gelatin, and almost completely sono-opaque.

This is the external surface of the simulant, and represented a major problem for the phantom.  It was impossible to image past this interfering layer.  I tried scraping the surface foam off, but to no avail.
I spent three shifts at the hospital trying to find a way to make the system workable.  At this point I had intentionally inoculated the surface with dust and dirt to attempt encourage microbial growth. At the three day point, no growth, but no apparent solution.

Ending my shift one morning, I had my "Eureka" moment.  One of the workmen was removing floor tiles by heating them with a propane torch.  Between my broken Spanish and his broken English, I was able to convey that I wanted to borrow his propane torch.  I quickly heated the surface of the phantom, melting the top foam layer.  It liquified and appeared to completely remove the foam layer.

I waited ten anxious minutes, visibly bouncing.  I placed the ultrasound transducer and was rewarded with two easily visible vessel simulants.  Cannulation was almost exactly the same (the new material seems somewhat more friable).

Six weeks later, the phantom was still visibly free of microbial growth (I don't have the patience or material to actually test for microbial growth beyond naked eye visualization).

I'm stuck at the next step.  I'm either casting a human arm and making a mould, or I'm developing some method to snake the vessels through the simulant to increase the difficulty in cannulation.

DIY Ultrasound Phantoms: Recipes, Part 1

I'm now on the fourth generation homemade ultrasound phantom. The recipe is pretty simple and low cost. I'm using store bought Knox gelatin, generic sugar-free psyllium fiber (Metamucil), and vein simulators (5mm Penrose drains). Before I link to the articles I used, I'm going to shoot the authors a quick email (The idea of using the above recipe is not my original idea). Right now I'm building the phantoms in cheap, flat food containers (ultra cheap tupperware clones). Each phantom is currently constructed of three "pours". Each pour uses the following recipe: 250-300cc's of boiling water 3 packets of Knox gelatin 1-2 tablespoons of sugar free psyllium fiber With the water at a boil, add the packets of Knox gelatin slowly. Some will probably clump up (This isn't a big deal. I'll go into that in a bit). While adding the gelatin, watch the boil, as it may boil over. Stir continuously. Once the gelatin is added, slowly add the psyllium fiber, again watching carefully and stirring continuously. If the mixture clumps a little bit, don't worry too much. If you are looking to create a relatively clear ultrasound phantom, pour the mixture into the mold (in my case, the cheap food storage container) through a strainer. This will catch most of the lumps. If you are looking to create a "Dirty" looking phantom, leave the clumps in. These clumps will sonographically appear as areas of varying tissue density. These inclusions mimic the appearance of real tissue. Our goal (at my hospital) is to create a better arm simulation for US guided IV insertion techniques. These inclusion bodies mimic scar tissue, varying tissue densities/types, and present a sonographic picture that is not as "cut and dried" as other vascular simulators. The cheap food containers that I am using hold 3-4 gelatin "pours". I have been using three pours for my prototypes. After each pour, I'm allowing the gelatin to firm up in the fridge for two hours, before pouring the next layer. After the first pour has firmed up, but before pouring the second pour, I'm putting down two penrose drains, filled with water/saline, to simulate vessels. One of the vessels I'm overfilling/pressurizing with 30% more fluid, to simulate an artery. My vessel simulators occasionally leak, so I'm not having tremendous success with the arterial simulation. Still, with the slight pressurization, the vessel does have a slightly different appearance when visualized sonographically. This is a practice, that once perfected, will enable students to differentiate between arteries and veins. I'm working on a method to create an automated pulse, so that the vessel is maintained under pressure and appears to pulsate.

Our sad state of affairs

I grew up reading Bloom County.  When I first started enjoying the strip, I'll admit, I didn't get all of the jokes.  The anxiety closet, Oliver Wendell Jones, the swimming hole, all of those, I got.  It took me awhile, but once I figured out what a "Tomato" was, well, I got it.  Pretty much all of it.  I laughed my face off when "The fishes were going to tear gas us".

For awhile I've felt that we (The United States) have become too divisive.  Our national pasttime has become tearing down opposing viewpoints, in the loudest, brashest manner.  The easy "food" for this is the media generated garbage that is spewed forth.  Some talking head gets on TV, says something, and is made "Media-Fact" before anyone takes a second to check the veracity of the statement.

I mean seriously, who gives a crap what Tyra Banks thinks about the election?  Do people really take Adam Baldwin seriously (Don't answer that, I'm finding out that Yes, people do).

My family is pretty representative of the voting demographic.  We've got staunch republicans, devoted democrats, and fringe idiots that seem to enjoy typifying the "arguing for arguings sake" problem.

The email exchanges were fast and furious.  It seems that the older generation is particularly mouthy, and willing to accept as gospel anything that is printed in the press (If it's on the internet, it must be true, right??!?).

The emails came to a screeching halt when my cousin piped up with some fact checking, and multi-source comparisons of facts.  It seems that she decided "Enough is enough", and just went out and checked some of the facts in these emails.  After the first email, she realized "Hey, I've struck gold", and started digging in all of the emails.  Her final email was about as bi-partisan as it could be (because both sides were spewing pure crap, in some cases), and pretty long.  A weak attempt was made by one party (who I'll just label as "fringey" for now) to attack one of her facts, but that was the end of the "Fact"-backed political email argument.

It seems that facts get in the way of a really good argument.  

I've had this conversation with my father (and a couple of others).  There have been several big media stories where the fundamental facts have been understated, or misconstrued.  I don't remember this happening when I was growing up.  I guess I had this childish innocence then, but I seem to remember being able to take newspapers as fundamentally accurate.  I was told that I was being naive, and that this had always been happening.  The media has always had a bias, in one way or another, and that the extremes have always been there.

From off stage comes Mr. Breathed, with an upsetting annoucement, and shoring up of my sanity and perceptions.

http://www.salon.com/books/feature/2008/10/18/opus/

I feel like a friend has died (again).  If Opus can't keep us "Real", and grounded, I am truly horrified.  Hopefully someone else will come back to tell us we need to attack dandelion puffballs, and kick back on the hill looking for shapes in the clouds.  We need to open the closet door and face down our anxieties (frequently with harsh, glaring realities).  

I'm glad that Mr. Breathed has stepped from behind his characters to tell people that there is a problem.  That we're heading for a bad place (hell, that we're already there).  That we should be paying attention to not just what we're saying, but what we're attacking.  That our fundamental tolerance is slipping, and this tolerance is what our country is supposed to be based on.  This is countered by our supposed grounding in reality.  Our education, our critical thinking, and our willingness to face realities, and force those around us to face those realities (if you haven't read page two of the interview linked above, make sure you read it).

I hope, either way, that Opus will retire to when he should be.  I hope that it includes his harem, a waterhole free of snakes, and an unlimited number of dandelions.  Either way, the tears on my face will be real, as a childhood friend will be passing on.

Prayer pimples for hairy fishnuts.