Ultrasound Phantoms: Designs, Configurations and Applications Heather L. Miller CIRS, Inc. Norfolk, VA Welcome, introduce self and topic. Disclose employment at CIRS May 12, 2003 ACMP Annual Meeting

What is an ultrasound phantom? Any structure that contains one or more materials that simulate a body of tissue in its interaction with ultrasound and is used to mimic ultrasonic interactions in the human body. What is an ultrasound phantom. Essentially it is any device that has materials that simulate certain acoustic properties of human tissue. May 12, 2003 ACMP Annual Meeting

Phantom Construction Tissue Mimicking Material (TMM) Targets Housings Phantoms are composed primarily of TMM. This is the substance that mimicks certain acoustic properties of human tissue. The phantom can be a homogeneous slab of TMM but more often than not it will contain some embedded test objects with known shape, size, and location. The TMM is typically protected by some type of protective housing. May 12, 2003 ACMP Annual Meeting

Tissue Mimicking Materials Agar ZerdineTM Urethanes Other epoxies liquids natural materials There are a wide variety of TMM. The solid forms are agar, zerdine (a water-based polymer) and urethanes. Other materials are also used such as epoxies to simulate bone, liquids for BMF and in homemade phantoms natural materials such as turkey breast with olives. May 12, 2003 ACMP Annual Meeting

Acoustic Properties Speed of Sound Attenuation Coefficient Backscatter Coefficient/Relative Contrast Elasticity Thermal Properties TMM are mimicking because they have certain controlled and measured acoustic properties. Speed of sound – discussion, attenuation discussion, contrast discussion using next slide too. Also newer interest is in characterizing the elastic for sonoelastography and thermal for HIFU. May 12, 2003 ACMP Annual Meeting

May 12, 2003 ACMP Annual Meeting Speed of sound enables the vertical distances to be measured correctly. In urethanes the sos is low so the wires are positioned to fool the ultrasound machine. Attenuation coefficient mimicks the depth of penetration in various tissues, I.e. how much energy is absorbed or transferred into heat by the TMM. Backscatter/relative contrast shows up as varing degrees of brightness on the image. May 12, 2003 ACMP Annual Meeting

Wires May 12, 2003 ACMP Annual Meeting One of the most commonly used embedded object are wires. These run the width of the phantom and show up as points on the ultrasound image. They are highly reflective materials such as nylon monofilament or stainless steel and very small diamters on the order of 0.1 mm. May 12, 2003 ACMP Annual Meeting

Various Masses May 12, 2003 ACMP Annual Meeting By altering the contrast of the TMM you can create various shapes to embed as masses. These may be spherical, cylindrical, egg shaped, organ shaped, really almost anything as all the materials are liquids injected into various shaped molds. The center image is really a CT image but it is from a triple modality abdominal phantom that can be used in ultrasound, CT or MRI and I think it really demonstrates the variety of forms the various TMM can take. May 12, 2003 ACMP Annual Meeting

Housings Serve to protect the TMM Thin films Rigid Containers Saran Polyurethane Rigid Containers ABS PVC Acrylic Most phantoms are going to be in some type of protective housing. Some are just going to be wrapped in a thin film of material while others will be in a rigid container with only the scan windows made from the thin films. Housings prevent the TMM from damage due to dessication and handling. It also allows the gels to maintain their shape ensuring that the targets haven’t moved. May 12, 2003 ACMP Annual Meeting

Phantom Quality Target Position Acoustic Properties Visual Inspection CMM machining Ultrasonic techniques Acoustic Properties Acoustic testing on individual batches Visual Inspection Phantoms are used for quality assurance so it is important that the quality of the phantom be high and verified. Targets location can be ensured using molds that are machined and inspected. Various ultrasonic techniques can verify target location once manufactured. Samples of the gel batches are taken and measured for various acoustic properties in test lab. And phantoms are subjected to rigorous visual inspection. May 12, 2003 ACMP Annual Meeting

Applications Training Demonstration Quality Assurance Research & Development Self explanatory slide May 12, 2003 ACMP Annual Meeting

Training Phantoms Biopsy Cryosurgery Brachytherapy HIFU IVUS 3D Training phantoms are to teach a user to either perform an interventional procedure or learn how to scan a particular body part. Here we have an IVUS phantom. The transducer would enter the center lumen and you would image various fluid filled lumens at known distances from the central lumen. May 12, 2003 ACMP Annual Meeting

Breast Biopsy May 12, 2003 ACMP Annual Meeting Breast biopsy phantoms are commonly used so physicians can practice the eye-hand coordination necessary to perform fine need aspirations of cysts or core-biopsy procedures. You can see the needle approaching the solid mass in this image. May 12, 2003 ACMP Annual Meeting

Demonstrations 3D Systems Brachytherapy Systems Mainly fetal ultrasound Brachytherapy Systems Demonstrate needle and seed visualization Other Sales demonstrations Sales people also utilize phantoms as demonstration tools. May 12, 2003 ACMP Annual Meeting

3D U/S Phantom May 12, 2003 ACMP Annual Meeting The 3D fetal phantom shows off the equipments surface reconstruction software. This could also be used as a training device for freehand 3D image acquisition. You must scan very smoothly and at a constant rate in order to acquire the best images. May 12, 2003 ACMP Annual Meeting

Demonstrations 3D Systems Brachytherapy Systems Mainly fetal ultrasound Brachytherapy Systems Demonstrate needle and seed visualization Other Sales demonstrations Brachytherapy phantoms are used to show needle and seed visualization May 12, 2003 ACMP Annual Meeting

Brachytherapy May 12, 2003 ACMP Annual Meeting This model contains the prostate gland, urethra, seminal vessicles, and rectum and can demonstrate the endocavity transducers. This again could be used for training for brachytherapy, biopsy, and cryosurgery procedures. You can think of the prostate as a patient, establish a treatment plan, embed the seeds and verify position with CT. May 12, 2003 ACMP Annual Meeting

QA/QC Equipment Selection Acceptance Testing Consistency checks Accreditation Programs ACR AIUM ICAVL The other use for phantoms is in quality assurance and quality control applications. They are useful tools when trying to compare equipment performance, when you are doing acceptance testing of newly acquired machines as well as ongoing consistency checks. I’m sure Zheng Feng will be going into much greater detail on this topic in the next presentation. QA phantoms are also useful for the various accredtation programs. May 12, 2003 ACMP Annual Meeting

May 12, 2003 ACMP Annual Meeting QA phantoms come in a wide variety of shapes and sizes. You have multi-purpose phantoms that can be used on a wide variety of equipment and then you have very specialized phantoms for use on Doppler systems or bracytherapy systems or very high frequency transducers. May 12, 2003 ACMP Annual Meeting

R& D Uses Product Development FDA Approval Process Basic Scientific Research Phantoms are also custom built for a variety of R&D uses. OEM utilize them during product development, they are an important component of 510 (k) applications and they you have people doing just basic scientific research that need something to scan. May 12, 2003 ACMP Annual Meeting

Manufacturers ATS Labs, Bridgeport, CT CIRS, Norfolk VA www.atslabs.com CIRS, Norfolk VA www.cirsinc.com Gammex RMI, Madison WI www.gammex.com In the states there are three main manufacturers of phantoms. A wide variety of dealers sell these phantoms as well. May 12, 2003 ACMP Annual Meeting

Future Developments Increased durability Increased longevity Keep pace with developments of ultrasound machines Thin Film phantom targets Smaller resolution point targets Phantom development parallels the developments in the ultrasound machines. As the machines become more sophisticated, so too will the phantoms. Right now people are working on trying to manufacture test objects that will push the resolution limits of the machines on the market. That means smaller, more closely spaced and more accurately described embedded objects. In addition, materials with greater durability and longevity are needed. Currently work is being done by the TSC committee within the AIUM to standardize the test methodology for absolute backscatter measurements. May 12, 2003 ACMP Annual Meeting

In Summary Phantoms contain various TMM Phantoms come in a wide variety of shapes and sizes Phantoms are utilized for a variety of purposes such as training, QA, and demonstrations Phantoms are useful tools May 12, 2003 ACMP Annual Meeting