Tag Archives: ALARA

Safely Using Diagnostic Ultrasound

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The clinical applications for diagnostic ultrasound have expanded tremendously since its introduction in the late 1950s thanks to technological advancements in both hardware and software, enabling rapid diagnoses at the patient bedside. With this expansion, the medical specialties employing ultrasound as a diagnostic tool have also increased substantially, resulting in a consistently growing group of new users across all levels of medical training and practice.

Ultrasound has long been understood as a low-cost, portable, and ionizing radiation-free imaging method, which has, in part, fueled this rapid expansion. However, ultrasound is ultimately a type of mechanical energy that is able to penetrate tissue, yielding the potential for bioeffects. Practically, the potential for bioeffects is measured through the thermal index (TI) and mechanical index (MI), which provide indicators of the temperature elevation and likelihood of cavitation, respectively, at a particular scan setting. While there have been no independently confirmed adverse effects in humans caused by current diagnostic instruments without contrast agents, biological effects have been reported in pre-clinical mammalian systems, emphasizing the importance of proper clinical use. As diagnostic ultrasound expands to new users and clinical applications, it is imperative that we continue to understand and assess these potential bioeffects and educate new ultrasound users to continue to use ultrasound safely.

The AIUM bioeffects committee has long undertaken this task, examining emerging technologies and making recommendations based on findings. Recently, the bioeffects committee updated its statement on the “Prudent Clinical Use and Safety of Diagnostic Ultrasound”. This statement reaffirms the promise of ultrasound as a safe and effective tool for diagnostic imaging when used properly by qualified health professionals.

Specifically, we emphasize three main ways to ensure diagnostic ultrasound is used safely:

  1. Monitor acoustic outputs—The likelihood of bioeffects can increase by increasing acoustic outputs, indicated by the thermal and mechanical indices. Exposure time should also be monitored, as increased exposure time can also increase the likelihood of bioeffects.
  2. Follow the ALARA principle—The as low as reasonably achievable (ALARA) principle maintains that users employ the lowest acoustic output and shortest scanning time to reasonably achieve diagnostic-quality images.
  3. Only allow qualified professionals to use ultrasound—Ultrasound should be used only by qualified health professionals to provide medical benefit to the patient.

As new diagnostic ultrasound technologies are developed and evaluated, it will continue to be critical to ensure new users understand the proper use of diagnostic ultrasound and the potential for bioeffects, particularly as the use of ultrasound expands beyond traditional use cases and into the future—perhaps even one day into the home!

Alycen Wiacek, PhD, is an engineer, ultrasound researcher, and educator, working to develop new ultrasound-based imaging technologies and improve the quality and diagnostic accuracy of ultrasound. She is a member of the AIUM Bioeffects Committee and is passionate about developing technology to increase access to high quality ultrasound.

Understanding the Basics of Medical Ultrasound Safety in Musculoskeletal Ultrasound

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Musculoskeletal ultrasound (MSK US) is an invaluable diagnostic tool that provides real-time, dynamic imaging of muscles, tendons, ligaments, joints, and soft tissues. Its advantages include being non-invasive, relatively low-cost, and free of ionizing radiation. However, to maximize its benefits and ensure patient safety, it is crucial for practitioners to understand and apply certain fundamental principles, including ALARA (As Low As Reasonably Achievable) and the Mechanical Index (MI). Here, we provide an overview of these concepts and other essential information for new users of MSK US.

ALARA Principle

The ALARA principle stands for “As Low As Reasonably Achievable” and is a cornerstone of safe ultrasound practice. It emphasizes minimizing the patient’s exposure to ultrasound energy while still obtaining the necessary diagnostic information.

Key Strategies to Apply ALARA:

1. Optimize Scanning Parameters: Use the lowest possible settings for power, gain, and exposure time that still yield diagnostic quality images. Avoid unnecessary Doppler applications, which use higher energy levels.

2. Adjust the Probe Position and Angle: Efficient probe manipulation can improve image quality without increasing power output. Use proper ergonomics to maintain consistent and effective contact with the patient’s skin.

3. Limit Scan Duration: Conduct scans efficiently to minimize exposure time. Pre-plan the examination to focus on areas of interest and avoid prolonged scanning.

By adhering to the ALARA principle, practitioners ensure that ultrasound procedures are both effective and safe.

Mechanical Index (MI)

The Mechanical Index (MI) is a parameter used to evaluate the potential for mechanical bioeffects, such as cavitation, which can occur during ultrasound procedures. It is calculated based on the peak negative pressure of the ultrasound wave and the frequency of the ultrasound.

Understanding MI Values:

  • Low MI (<0.3): Safe for sensitive tissues; minimal risk of cavitation.
  • Moderate MI (0.3–0.7): Generally considered safe for routine diagnostic imaging.
  • High MI (>0.7): Increased risk of mechanical bioeffects; should be used with caution and justified by clinical need.

To maintain patient safety, it is essential to monitor and adjust the MI, especially during prolonged or intensive scans.

Thermal Index (TI)

Another crucial parameter in MSK US is the Thermal Index (TI), which estimates the potential for tissue heating. The TI is influenced by the duration of the ultrasound exposure and the intensity of the ultrasound beam.

Categories of TI:

  • TIS (Soft Tissue): Applies to imaging of soft tissues and abdominal organs.
  • TIB (Bone): Relevant for imaging near bone structures.
  • TIC (Cranial): Pertains to imaging the fetal skull or neonatal head.

For MSK US, TIB is the most relevant as it applies to imaging around bones and joints. Maintaining an appropriate TI helps prevent thermal damage to tissues.

Essential MSK US Techniques

1. Probe Selection: Use the appropriate probe for the area being examined. High-frequency linear probes (7–15 MHz) are commonly used for superficial structures like tendons and muscles, while lower-frequency probes are better for deeper structures.

2. Patient Positioning: Proper patient positioning is crucial for optimal imaging. Ensure the area of interest is accessible and the patient is comfortable to avoid movement that can degrade image quality.

3. Image Optimization: Adjust the depth, focus, gain, and time-gain compensation (TGC) to enhance image quality. Clear visualization of the anatomy is essential for accurate diagnosis.

4. Dynamic Examination: Utilize the dynamic nature of ultrasound to assess the movement and function of musculoskeletal structures. Real-time imaging can help identify abnormalities that static imaging may miss.

5. Documentation: Capture and store high-quality images and clips of the relevant findings. Proper documentation supports clinical decisions and facilitates communication with other healthcare providers.

Conclusion

Performing musculoskeletal ultrasound requires a solid understanding of key safety principles, such as ALARA and MI, as well as technical skills in image optimization and patient positioning. By adhering to these guidelines, practitioners can ensure safe and effective use of MSK US, providing valuable insights into musculoskeletal conditions and enhancing patient care.

Cynthia Owens, BA, is the Publications Coordinator for the American Institute of Ultrasound in Medicine (AIUM).

Interested in learning more about the basics of ultrasound? Check out these resources from the American Institute of Ultrasound in Medicine:

The Sonographer Scope of Practice: what you need to know

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Why is it important to read the Sonographer Scope of Practice?

  • A scope of practice clearly articulates the activities and processes healthcare professionals can perform.
  • A scope of practice limits the activities of a healthcare professional based on specific education, training, and competency requirements based on regulations, standards, and laws.
  • Very few states regulate the education, competency, and certification of sonographers.
  • The Sonographer Scope of Practice is our guiding document that describes the boundaries of our profession.

This year (2024), the Society of Diagnostic Medical Sonography (SDMS) released the latest revision of the Scope of Practice and Clinical Standards for the Diagnostic Medical Sonographer (The Scope) which encompasses the changes and growth in technology and the expansion in the roles of sonographers. I was excited to represent the American Institute of Ultrasound in Medicine (AIUM) in this revision process, and glad that the AIUM Board of Governors voted again to continue to support The Scope.

This comprehensive document sets forth the most current standards and expectations for sonographers, emphasizing patient care, safety, and the evolving role of sonographers in healthcare.

I asked colleague Jaime Taylor-Fujikawa, RDMS, RDCS, why she feels The Scope is important. Her first reason was because it is not stagnant. She stated that “the sonographer profession continues to expand and evolve, and The Scope has changed with the times.” Jaime is a sonographer of 21 years, a long-time member of the AIUM, and she lives in 1 of only 4 states that requires licensure of sonographers. She has taken certification exams in OB, Adult Echo, Pediatric Echo, and Fetal Echo.

Did you know that though certification of sonographers is considered the standard of care, it is still considered voluntary except in those states that require licensure?

The sonographer is defined as an individual who performs diagnostic exams and procedures, acquiring images and other pertinent information to provide to the interpreting physician. Sonographers do not practice independently and function as a delegate of the physician. In brief, we

  • Follow written policies, protocols, and guidelines.
  • Apply principles of safe use (ALARA) for the patient, ourselves, and the healthcare team.
  • Commit to ongoing education to increase competence with increasing advancements.
  • Acquire appropriate training and experience in examinations and specialty areas in which they perform.

This is but a brief overview of The Scope. A few areas that were added/expanded included

  • The role of the advanced practice sonographer (under physician supervision)
    • As an evolving role for those with higher levels of education, training, and experience,
    • Which may be identified with advanced job titles such as ultrasound practitioner, advanced cardiac sonographer, advanced sonographer, and/or with an advanced certification (currently there is only 1 advanced certification available)
  • The use of contrast, which has been expanded and is now woven strategically throughout the document with more succinct guidelines of the sonographer’s role.
  • The expansion of safety principles to increase focus on prevention of work-related musculoskeletal disorders (WRMSD) to encourage
    • Maintenance of an environment to avoid injuries,Implementation and participation in programs designed to reduce WRMSD, and
    • Reporting signs and symptoms of WRMSD.

A few areas of The Scope are outlined here, and it contains an overarching theme of essential commitment (from sonographers) to professional growth and development and adherence to our professional standards, regulations, and accreditation standards that guide our actions to serve our patients competently and safely. The Scope compels us to

  • Treat all patients with kindness, compassion, dignity, and respect.
  • Perform examinations only with a medical order.
    • Exceptions for educational programs, in-service training, CME activities, research
  • Perform only those examinations for which we are educated, trained, experienced, and competent, and (where applicable) certified.
  • Adhere to the scope of practice and other professional documents.

In the absence of licensure, it is imperative that sonographers follow The Scope and that employers hire certified sonographers so that patients can receive quality ultrasound examinations and excellent patient care.

Do you work with a sonographer? Are they certified? Do you know their areas of certification? You can find the complete Scope of Practice and Clinical Standards for the Diagnostic Medical Sonographer here https://www.sdms.org/about/who-we-are/scope-of-practice.

Charlotte Henningsen, MS, RT(R), RDMS, RVT, FSDMS, FAIUM, is currently an Adjunct Faculty at AdventHealth University. She has taken certification exams in Abdomen,
OB/Gyn, Pediatric Sonography, Breast, Fetal Echo, and Vascular Technology. She
has been a member of AIUM since 1989 and has served on the AIUM Board as 2nd
Vice President, and most recently co-chaired the Practice Principles on
Work-Related Musculoskeletal Disorders.

Handle the Scan with Care

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Anytime one begins an obstetrical scan, there is a ritual that precedes our privileged access into an otherwise inaccessible place pulsating with life, hope and promise. The trilogy of preparing the patient, applying the gel, and selecting the transducer helps us transition as we open a window to the womb, sharing a highly anticipated and treasured moment with the family.

old windowWhile this privileged access may provide priceless reassurance, it is accompanied by a huge responsibility for the sonologist who is attempting to make sense of what is seen while trying to decide how to share the information with the family.

As diagnosticians, we are taught to be vigilant, careful and meticulous, making note of every single finding. We employ the most sophisticated machines and the importance of being non-paternalistic is deeply engrained in our brains. Yet at the same time, care and caring must come into play if we need to break news that may shatter dreams or induce significant parental anxiety.

Personally I find that the most challenging cases are those in which various isolated sonographic markers may be detected. The struggle between wanting to be scientific, factual and transparent and the fear of labeling an otherwise healthy being and worrying a hopeful parent becomes paramount. This is becoming more commonplace nowadays with the advancing technology as we delve into fetal evaluations with much more detail and at earlier points in gestation. We must not mistake normal developmental findings with pathology. We must be careful with enhanced image resolution and the employment of harmonics as these may increase tissue echogenicity and lead to over diagnosis of physiologic “cysts” in fluid producing structures.

With the continuing advancement of the technological capabilities of this most versatile of medical diagnostic modalities and its evolving portability, the number of probe-handlers globally is increasing exponentially across the disciplines. The problem is that education, training and experience are not uniform. The expertise to discuss the implications of various sonographic findings, particularly soft markers, and to recognize serious abnormalities, may be lacking. Despite the well-established positive impact of prenatal diagnosis, allowing us to prepare families and formulate the optimal plan of care, it may also be a double-edged sword, particularly in inexperienced hands.  As such, and in keeping with the mission of the AIUM and its communities of practice, the importance of proper training cannot be overstated. One must adhere to the basic sonographic teachings, employ the ALARA principle, and implement practice parameters when incorporating sonography into daily clinical practice. Referral to centers of excellence, whenever there may be doubt, is critical. Sound judgment remains the key to utilizing ultrasound first.

A new life is purity in the absolute form: a blank sheet of paper. Much caution must be exercised before any marks are made. Every word uttered has the potential of tainting the page, of taking away hope, of falsely “labeling” this promising life before it has even come into physical being. “First do no harm” should continue to echo in our brains and we must always proceed with caution, and tread with care.

What’s your opinion on the quality issue? Do you see a wide range of quality in ultrasound scanning?  Comment below or let us know on Twitter: @AIUM_Ultrasound.

Reem S. Abu-Rustum, MD, FACOG, FACS, FAIUM, is the Director of the Center For Advanced Fetal Care in Tripoli, Lebanon. She has served the AIUM in several capacities, including her current role on the AIUM Board of Governors.

  • Image adapted from A Practical Guide to 3D Ultrasound. RS Abu-Rustum. CRC Press 2015.