Light Density & The Truth about Pods/Beds

In the world of PBM pods, power density (measured in Fluence - W/m2) is one of the most important factors in determining outcomes, so it has become one of the most debated and manipulated marketing points. We hate to speak negatively about anyone but we struggle with the fact that one manufacturer has gone to great lengths to fabricate videos showing totally manipulated fluency values for their product. Like 5x more power than the system actually delivers. Because of this one group, we recommend that every buyer use a inexpensive solar test meter to confirm the specs before they drop $60,000+ on a pod.

Higher power pods cost more but deliver faster results than lower power machine, so almost every manufacturer claims "the most powerful pod" in order to sell their systems. We are an engineering-driven company so of course, we test everything including our competitor's products to make sure we are delivering the best performance and value. BioPhotonica really makes the most powerful pods and we can prove it.

Below, we have published some of our test data. We have also published information about inexpensive test meters that will do a good job of comparing light output in pods. If you are considering buying a pod, we will be happy to send you a test meter or help you buy a new test meter on Amazon so you can make sure you are getting the light density that you want before it is too late.

So how does a consumer learn the truth?

Digging Deeper

Before we review our test data, lets reviews the basics of any type of measurement. What everyone mainly cares about with pod is fluency but understanding absolute measurements, calibration, and variability are important because the control the accuracy of the fluency measurements.

Fluence

Fluency is the measure of light density, The units are W/M2 or mW/cm2. In PBM, we care a lot of about fluency because it determines dosage and dosage determined results.

Total dosage absorbed into the tissue = fluency X surface area X treatment time.

Since dosage is one the most critical factors in determining efficacy in PBM, it is important to understand the fluency of each Pod. Our measurements and analysis show that the Regen Q8 Pod provides significantly higher dosage than both competing options. 

Absolute & Relative Measurements

In any type of measurement, results can be either absolute or relative. In the US, absolute measurements must be based a NIST traceable primary calibration standard that is accurate, reliable, and used in and almost identical to the test environment. All light measurements are based on a calibration so every measurement device, that is not NIST calibrated, to an almost identical light source, will give you a different absolute reading. For this reason, most pod buyers will have to rely on relative light measurements.

Luckily this can be done with an expensive solar light meter. As a buyer, your best option is to use the exact same device on multiple Pods without recalibrating between systems. The produces numbers that allow users to see which system has the highest and lowest fluency. Because the calibration and sensitivity of each test device is different, we see different results for each test device but these relative numbers are perfect for comparing systems.

Calibration

Light measurement devices must be calibrated (usually at the min and max of the measurement range) against NIST traceable reference sources. Based on the quality of the reference sources, these systems can easily be recalibrated to either display an accurate or an unrealistic output. This is why you use a pre-calibrated device and not change the reference values if you want to get a realistic fluency.

This is how some company's mislead people. If you perform a calibration in a dark room and tell the system that is in direct sunlight, then every future measurement will show that the test source (like a Pod) are much brighter than it truly is. By using a none NIST traceable calibration source, we can make the meter show any value we want. This is why it is important to use a precalibrated light meter and not a "user calibrated" calibrated light meter like a spectrometer.

Max and Min Measurements

As you move a test meter around a large light emitter, you naturally see undesirable variations in the output of the source. Most test equipment does internal averaging to avoid looking like a random number generator. This averaging is over a specified time and makes the output more stable and reliable. In our analysis, we use used the light meters to measure maximum values over a large part of the treatment surface where the skin would be during a therapy session. We also used one of the meters to measure the minimum value. By measuring the maximum and minimum values, we get an indication of missing, burned out or a poorly designed array. A better system will have less variation between max (bright) and min (dim) areas. 

Analysis

This was created to do a comparative analysis of the light pods. Due to legal limitations, we cannot publish their actual names.  In our test compare the different Pods we used 3 separate light meters:

1. TENMARS-206 Solar Power Meter
2. TES-1333 Solar Power Meter
3. Sanwa LP10 Laser Power Meter

Note that while the solar power meters provide readings in Watts/Meter2 (W/M2 ), the Sanwa only provides reading in mW with no area specified, so these readings are not comparable in absolute terms, but again, there continues to value in relative measurements.

The following table shows our light meter readings and table after that shows the incremental difference between the ReGen Pod and the competing systems.

Our Light Measurements

Light Pod
Tenmars (W/M2)
Maximum
TES (W/M2)
Maximum
Sanwa (mW)
Maximum
Sanwa (mW)
Minimum
ReGen Q8 706 698.8 23.28 19.46
(84% of Max)

Nova 524 453.1 19.53 9.05 *1
(46% of Max)
TL360 132 119.2 4.25 4.03
(95% of Max}

*1 The variation between high-density areas and low-density areas is 54%. This is large variation and implies that dosage across the surface area will be inconsistent.

*2 This data is based on one of the original pods and has was confirm in 2/22 before we pulled out a TL360 from a customer and replaced it with a ReGen Pod. We have video of the testing that we can share if you contact us.

Summary of Results

Light Pod
Tenmars (%)
Maximum
TES (%)
Maximum
Sanwa (%)
Maximum
Average of
All Meters (%)
ReGen Q8 vs NT35% Increase54% Increase19% Increase36% Increase
ReGen Q8 vs TL360535% Increase586% Increase548% Increase556% Increase