Ultrasound gel learning notes

How to make your own ultrasound gel - Janice Boughton Tuesday, March 12, 2013

http://blog.acpinternist.org/2013/03/how-to-make-your-own-ultrasound-gel.html

I have been doing lots of bedside ultrasound lately and realized how useful it would be in areas far off the beaten track, like Haiti, for instance. With a bedside ultrasound (mine fits in my pocket) I could diagnose heart disease, kidney and gallbladder problems, various cancers as well as lung and intestinal diseases.

Then I realized that I would have to take a whole bunch of ultrasound gel with me, which would mean that I would have to check luggage, which is a real pain when traveling light to a place where luggage disappears. I heard that you can use water, or spit, in a pinch, or even lotion, though oil-based coupling media apparently break down the surface of the transducer. 

Ultrasound requires an aqueous interface between the transducer and the skin or else all you see is black. Ultrasound gel is a clear goo, looks like hair gel or aloe vera, and is made by several companies out of various combinations of propylene glycol, glycerine, perfume, dyes, phenoxyethanol or carbapol R 940 polymer, along with lots of water. It is hard to find this information, but it is available in the material data safety sheets for the various companies that make it. The recipes are proprietary. Ultrasound gel is not super expensive, but it is not that easy to find in a store or in a developing country. It costs about $25 for 5 liters on Amazon, or $5 for a nice 8.7 oz squeeze bottle. It smells ever so slightly medicinal and leaves a sticky, then white residue as it dries.

There should really be some sort of powder that you mix up with water that makes ultrasound gel so we don't have to be shipping the water part of it, which is undoubtedly about 99% of the contents, long distances. But there isn't a powder. I have been looking. No instant ultrasound gel.

With a mixture of optimism and singularity of purpose I went to the kitchen and tried out six different recipes for an aqueous goo that would transmit sound waves. I thought that I could make ultrasound jam out of water and pectin, but that doesn't really work. Obviously there is something magic about fruit that makes pectin gel, maybe the acid or the sugar. Without fruit, even no-sugar pectin becomes about the consistency of spit. (I also tried spit, which does work, but has various obvious drawbacks.) I tried plain gelatin and water and got beautiful clear gelatin, which falls off the transducer, and kind of works, but is also messy. I tried corn starch and water, as if making extremely boring gravy. That was lovely and white, but the water wants to come out of it so it just slides off the transducer. I tried tapioca flour which I boiled with water, producing a nice clear, very mucoid gel which dries like glue on the skin and is very uncomfortable. I tried xanthan gum, a bacterial polysaccharide used to bind and thicken, boiled and cooled, and although it thickens the water it is slimy and falls off the transducer and makes a mess.

The recipe that worked (and worked great) is guar gum, salt and water. Guar gum has been used for a very long time in countries like India and Pakistan to thicken food and is now used often by people who can't eat gluten, to thicken gravies and make breads. Guar gum is the ground endosperm of the guar bean, which is very rich in a carbohydrate that avidly absorbs water. Guar beans are also eaten green and the pods are used as a vegetable ingredient after shelling out the beans. Guar gum is available in the flour section of many grocery stores and costs about $10 for a 220 gram bag. It is purported to be good for diarrhea, constipation, diabetes and lowering cholesterol. It has been added to infant tube feed formula in intensive care units to decrease stool frequency.

I messed with the recipe awhile and came up with a very nice slightly caramel tinged ultrasound gel this way:

1. Mix 2 teaspoons of guar gum with 1-2 teaspoons of salt. (The amount of salt isn't vitally important since it is just added to keep the guar gum from clumping.
Using slightly less than a teaspoon of salt per 2 cups makes a gel with which is isotonic, which would be ideal for use near eyes or other mucus membranes or on open wounds).

2. Boil two cups of water.

3. Slowly sprinkle the guar gum/salt mixture into the boiling water while stirring vigorously with a fork or whisk.

4. Boil for about 1-2 minutes until thick and well mixed.

5. Cool before using. Save lives.

I tried it and it works at least as well as the proprietary stuff, and probably doesn't dry out quite as fast. It wipes off easily and doesn't leave a sticky film. Even though it is not entirely transparent, there is no reduction in the quality of the ultrasound image compared with the standard clear ultrasound gel. 

It costs about 25 cents for a half pint, is sterile when you have finished making it and is completely non-toxic. The ingredients are available in many developing countries, not to mention the U.S. It is edible. It is not particularly bacteriostatic, though it could be made bacteriostatic with a little EDTA (but then it wouldn't be edible). It is probably best made and used for two or three days, then discarded if unused, though I kept some in a clean bottle at room temperature and it was stable and smelled fresh for over a week.

It is quite thick, like regular ultrasound gel, so it is a bit of a trick to get it into a squeeze bottle. A large bore funnel works, or the cooled gel can be squeezed into the bottle out of the cut end of a plastic bag. It can also be kept in a jar and used with a spoon.

This is kind of exciting. Now I will no longer be dependent on ultrasound gel manufacturers. If I was in Haiti, either I or someone at the house where I was staying could make up a batch of this the night before clinic and I would have fresh clean ultrasound gel with which I could be generous in my scans. The water wouldn't even have to be sterile since the stuff is boiled when it is made. Let there now be ultrasound in places that Amazon.com does not reach!

Janice Boughton, MD, ACP Member, practiced in the Seattle area for four years and in rural Idaho for 17 years before deciding to take a few years off to see more places, learn more about medicine and increase her knowledge base and perspective by practicing hospital and primary care medicine as a locum tenens physician. She lives in Idaho when not traveling. Disturbed by various aspects of the practice of medicine that make no sense and concerned about the cost of providing health care to every American, she blogs at Why is American Health care so expensive?, where this post originally appeared.

Labels: guest post, handheld ultrasound, health care cost, Janice Boughton, Why is American health care so expensive?

posted by Janice Boughton, MD, FACP at 11:00 AM






Ultrasound Gel - What It Is and How It Is Used By Rudy Garay

http://ezinearticles.com/?Ultrasound-Gel---What-It-Is-and-How-It-Is-Used&id=6394828

Before a sonographer (medical professional who operates an imaging device or ultrasound) proceeds to perform an ultrasound scan, you'll notice that a layer of thick gel is applied on the belly of a pregnant woman. That gel is water-based and serves as lubricant throughout the procedure to produce a great image of the growing baby inside the mother's womb. To give you a broader understanding about this gel, let me discussed first where is this gel made from.

The typical gel for ultrasound contains Polyacrylamide or the byproduct of the gel that undergone process of electrophoresis (also known as cataphoresis which defines the relative motion of dispersing particles in a solution under the state of dimensionally uniform electric field) which is a common method in biochemistry that aims to separate macromolecules. This ultrasound gel is safe and non-toxic for both sonographer and patient, it contains some chemicals responsible for its texture, thickness and color.

Chemicals are differentiated as Propylene Glycol, Glycerin, Phenoxyethanol or Colorant. Propylene Glycol is commonly used in pharmaceutical and cosmetic purposes, its chemical molecule in nature is stable and neutral which is not reactive if combined with other substances. It also serves as emulsifier, helps in holding and binding water molecules and other substances. Glycerin is a compound commonly used in soap production. It's characterized as colorless and sweet in taste, Polyol is its main component which is a molecule containing alcohol with multiple hydroxyl groups attached to it which helps absorbs water from air thus making it a good solvent. Phenoxyethanol is a colorless oil-based and water soluble solution that is consider as glycolether, commonly used in derma products but somehow over usage can cause damage or toxicity of the central nervous system. Colorant is synthetic dyes of FD&C Blue No. 1 that is made out of petroleum are usually used in ultrasound gel. These types of dyes are mostly found in foods and cosmetics products.

Upon performing the ultrasound imaging procedure the medical professional applies the gel on the surface of the skin, it is clear, thick and adheres easily. It is normally cold, however there are ultrasound gel warmers to warm it before use. The gel serves as the medium in the transmission of soundwaves. After the application, the transducer is then place and manipulated on the target area where the gel absorbs all air displaying clear and high quality images. It serves as the bridge of the soundwaves where it passes by and bounces back to the transducer, then transducers pick-up the waves and processed it to visualize the internal structure of the body organ. Ultrasound is helpful not only for pregnant women who wants to see the baby inside their tummy but also for the diagnosis of tumors whether benign or malignant, early detection of metastasis of cancer cells, abnormal masses and visualization of hollow internal organs. After the ultrasound procedure is done, the ultrasound gel is wiped off, the image produce is printed out or saved for patient's benefits and hospital record purposes.

Smartsound Ultrasound (DrSmart.com) is a leading provider of ultrasound equipment and related supplies such as ultrasound gel used in ultrasound procedures.

Article Source: http://EzineArticles.com/?expert=Rudy_Garay



The Ingredients in Ultrasound Gel: Polyacrylamide Gel's Properties - By Jessica Jewell, eHow Contributor
 
http://www.ehow.com/list_7837160_ingredients-gel-polyacrylamide-gels-properties.html

Polyacrylamide is a gel created by the process of electrophoresis, a technique used in biochemistry and molecular biology to separate macromolecules. It is a cross-linked polymer of acrylamide and because it is an acoustic coupling medium, it can be used for focused ultrasound therapy. While acrylamide is highly toxic, the ingredients used to make ultrasound gel are non-toxic and safe to use by trained medical professionals.


Ultrasound covers and sonographic gels are embryo-toxic and could be replaced by non-toxic polyethylene bags and paraffin oil.

http://www.ncbi.nlm.nih.gov/pubmed/9756303

Van der Auwera I, D'Hooghe TM. Hum Reprod. 1998 Aug;13(8):2234-7.  PMID: 9756303 [PubMed - indexed for MEDLINE]

Abstract

The objective of this study was to test the hypothesis that ultrasound covers and sonographic gels, used during vaginal ultrasound, are toxic for mouse embryonic development in vitro. A prospective randomized design was used on pronucleate ova of F1 hybrid CBA x C57Bl female mice. The mice were superovulated with pregnant mare's serum gonadotrophin and human chorionic gonadotrophin and mated with CBA x C57Bl males. The pronucleate ova were randomly divided between culture media with the addition of commercially available ultrasound covers and sonographic gels in different concentrations. As controls and potential alternatives, plastic polyethylene bags and paraffin oil were tested simultaneously. Embryo-toxicity was assessed by documenting cleavage capacity, blastocyst formation and embryo degeneration in vitro. Exposure of culture medium to the ultrasound covers and sonographic gels tested resulted in a severely reduced cleavage capacity, a high incidence of embryo degeneration and absent or impaired blastocyst formation. This toxic effect could be reduced by high dilutions in vitro. In contrast, plastic polyethylene bags and paraffin oil had no influence on in-vitro development of mouse ova. We conclude that commercially available ultrasound latex covers and sonographic gels are toxic for mouse embryos and can potentially influence embryonic development during infertility treatment. It is safer to perform vaginal ultrasonic measurements using non-toxic paraffin oil (as contact fluid) and plastic polyethylene bags (as ultrasonic cover).





ebay ultrasoud gel

http://www.ebay.com/bhp/ultrasound-gel

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