Application Note

The LymphScanner is a non-invasive hand-held device intended for the assessment of localized percentage water content (PWC) in human skin at lymphedema sites after surgery for breast cancer. Applicability ranges from undetectable preclinical lymphedema to advanced lymphedema. The device integrating the main unit and the measurement probe can be used to aid in forming a clinical judgement of skin edema by a healthcare professional. Measurement results are displayed in seconds after applying the measurement probe on skin surface. The LymphScanner is intended to be used by healthcare professionals in small or large lymphedema treatment centers.

Measurement principle

The LymphScanner consists of an electronic control unit and integrated probe to measure tissue dielectric constant (TDC) of the measurement site. The device generates a high-frequency electromagnetic (EM) wave and sends the wave into the coaxial probe and skin. The reflected EM wave contains information of tissue water content. The LymphScanner automatically converts the measured TDC value into percentage water content (PWC) of the measurement site. A high PWC indicates a high tissue water content. The parameter PWC is an accurate indicator of tissue water content when tracking tissue water changes over time or assessing inter-site differences.

Guidelines for performing measurements

Breast cancer related lymphedema (BCRL) can be assessed by calculating inter-arm percentage water content (PWC) ratio. It is recommended to use the inter-arm PWC ratio since the inter-arm PWC ratio is independent of measurement site^1-3, gender¹, age⁴, BMI^5,6, handedness^1,3,7, diurnal effects⁸ or race⁹.

The inter-arm PWC ratio is calculated using the formula:

PWC ratio = PWC at affected site of operated arm / PWC at equivalent site of contralateral healthy arm

where the PWC measurement value of the affected arm is divided by PWC value of the non-affected contralateral arm skin site.

Threshold value for the assessment of BCRL

Recommended threshold value for inter-arm PWC ratio is 1.20¹⁰. This threshold (1.20) illustrates that lymphedema site has 20 % more interstitial fluid compared with contralateral measurement site in healthy arm.

Measurement sites

Inter-arm PWC ratios are typically measured on medially, ventrally or dorsally localized skin sites 5-15 cm distally and proximally from antecubital crease¹¹. The user is also free to assess inter-arm PWC ratios at other anatomical sites (like anterior or lateral thorax and axilla) where lymphedema might also manifest. Typical absolute PWC values of healthy female forearm and upper arm range between 27 % and 35 % ¹².

Delfin instruments for detecting lymphedema

Delfin Technologies has three different instruments for assessing edema or lymphedema utilizing TDC technology. All these instruments can be used for early detection of lymphedema and for the assessment of treatment-related effects. These instruments are the LymphScanner, MoistureMeterD Compact and multiprobe MoistureMeterD. There are nearly 70 international articles on the use of these instruments with lymphedema.

Medical device status

Multiprobe MoistureMeterD: Medical product Class IIa (EU), FDA clearance 510(k)

LymphScanner: Medical product Class IIa (EU)

MoistureMeterD Compact: Medical product Class IIa (EU)

Delfin Technologies Ltd

info@delfintech.com

www.delfintech.com

References:

1. Mayrovitz et al, Lymphology 48: 15-23, 2015.
2. Koehler et al, Lymphat Res Biol 17: 308-315, 2019.
3. Mayrovitz, Lymphat Res Biol 17: 316-321, 2019.
4. Mayrovitz et al, Clin Physiol Funct Imaging 37: 198-204, 2017.
5. Mayrovitz et al, Lymphology 52: 18-24, 2019.
6. Mayrovitz et al, Skin Research Technology 26(2): 226-233, 2020.
7. Mayrovitz et al, Clin Physiol Funct Imaging 38: 670–675, 2018.
8. Mayrovitz, Biomedical Physics & Engineering Express 3(4): 047001, 2017.
9. Mayrovitz et al, Skin Research Technology 23:471–478, 2017.
10. Mayrovitz et al, Lymphology 47: 142-150, 2014.
11. Karlsson et al, Lymphat Res Biol 18(3): 219-225, 2020.
12. Mayrovitz HN, Assessing free and bound water in skin at 300MHz using tissue dielectric constant measurements with the MoistureMeterD in: Lymphedema: Presentation, Diagnosis and Treatment. Eds: Greene AK, Brorson H and Slavin SA, Springer 2015, Chapter 13, pages 133-148, ISBN 978-3-319-14492-4.