In the world of PBM pods, light density or fluency (measured in mW/cm2 or 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. Based on our recent work with the military, we have found that most manufacturers are claiming more than they deliver and that at least one manufacturer is claiming their pod has an measurable fluency of less than 25% of their claimed output. BUYER BEWARE. It is because of these groups, we recommend that every buyer test their prospective system before they drop $60,000+ on a pod or light bed. Higher fluency pods cost more but deliver faster results than lower fluency machines, so almost every manufacturer claims "the most powerful pod" in order to sell their systems. As an engineering-driven company, we test everything including our competitor's products to make sure we are delivering the best performance and value and we can prove it.
Getting to the truth is that simple because of the physics and costs in light measurements. When testing fluency, some measures are based on true or"absolute" test meters and some is based inexpensive "relative" test meters. The "relative" meters (like solar output) are not very accurate but they will allow you to catch the lies that some pod manufacturers are publishing. If you are considering buying a pod, you can measure any pod we have installed across the country and compare it to the competition using the same device and you will get a "relative" comparison. If you want to see the "absolute" light densities, you have to test each wavelength individually and you must use a higher cost calibrated meter that will give you "absolute" measurements. With the right equipment and process, it is possible to determine the fluency of a light source to within 3% of the actual.
Also, keep in mind that the ReGen Pod provide this fluency even over the entire body. Panels and one-sided beds might have a respectable light density but the light is only distributed over a areas as small as 5% of the surface area in a ReGen Pod. In some case, this means means that you will have to increase the treatment time by up 20 times to achieve the same dosage. The average session in a ReGen Pod is 15 -18 minutes. To get the same dosage with low quality systems can take 2-6 hours per day. This is not practical for most people or businesses.
Fluency is the measure of light density, The units are usually expressed in mW/cm2 or sometime W/M2. In PhotoBioModulation (PBM), we care a lot of about fluency because it determines dosage and just like in pharmaceuticals, dosage determined results.
Total dosage (J) absorbed into the tissue = fluency (mW/cm2) X surface area (cm2) X treatment time (seconds) / 1000
According to Harvard, the average person has a total surface area of 18,000 cm2 and we know that 1000mW or 1 Watt will deliver 1J/sec so anyone can do the math and see how critical fluency to compare different light systems.
Since dosage is one the most critical factors in determining efficacy in PBM, it is important to know the fluency of any PBM system and this must be measured to get the true number. The power consumption of the system will give you an indication of the scope of the fluency but there is a wide range of efficiencies in light sources. The goal with any PBM system is to deliver as much of the light into the tissue as possible to reduce costs and treatment times. Cheaper light sources tend to waste a lot of the energy in heat. Pods, unlike IR saunas, are trying to maximize a photo-chemical reaction in the body and not a photo-thermal reaction so the efficiency is a key factor in getting the best results. Our measurements and analysis show that the ReGen Q8 Pod provides significantly higher fluency than any competing options.
In any type of measurement, results can be either absolute or relative. After a light measurement sensor is built, the sensor and electronics must be tested using a set of NIST traceable light sources to correct for the lack of performance across the range that the meter will be used in the testing. The electronics can then correct for variations in sensor quality and repeatable produce accurate outputs. This calibration must be done at wavelengths that are very similar to the application that the meter will used so that the factors will properly correct for the physical limitations of the measurement sensor.
It is the calibration factors that converts the "relative" measurements to a "absolute" measurements. Absolute fluency requires a set of calibration factors that are based on testing the light sensor against a set of NIST traceable light sources at the similar wavelengths to the test system. Each wavelengths or range if wavelengths will have a calibration factor. A good piece of test equipment will include a calibration report that show what factors are used to correct for the sensors variations. Working in the RED to IR range that is most common in pods, we see calibration factors ranging from 1 to 4. This means that without multiple correction factors, the output readings could be off by 400%.
The worst problem is that some systems allow the owner to enter their own calibration factors. With these systems, you could enter a calibration factor of +10x for example and the meter will display a fluency that is 10 times brighter than actual. Some manufacturers/distributors have published video showing this "little trick". You want to claim that your pod has a fluency of 120mW/cm2, just enter the desired calibration factor.
Fortunately, there are light meters that are designed to work in the range used in pods and they have accuracies of 3% if used properly. To get the highest accuracy, you must test each wavelength group individually so that the calibration factors are only applied appropriately wavelength. From our testing, we see that applying the correction factor for 630nm to the 940nm, for example, could results in errors in the 400% range since the calibration factor for 630mm is much higher than it is for 940nm. For lower-quality pods without individual wavelength control, there is no way to get accurate measurements over the full range that the pod is designed to be used for.
We use an Ophir Starlight with a 7Z02410 (PD300) sensor with a range of 430nm - 1100nm and an accuracy of 3% in the range of 400nm - 980nm. This system costs $2-3K. Our measurements were audited and confirmed by the independent group so we feel like this is the gold standard for light measurement.
Please contact us to get a copy of our test data that you can confirm. We can not publish it due to legal complications.
If you can not get access to a fully calibrated 3% accurate light meter like the Ophir, you can get a rough "relative" measurement using a low cost solar meter that cost less than $150.
This is only for comparing very similar pods with similar wavelengths. It is not accurate but it can be used to to determine the rough scale of the output.
Due to legal limitations, we cannot publish their actual names. This will not give you absolute measurements but it will help you understand now some companies totally misrepresent thier products.
In our test, we compared 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.
| Light Pod |
Tenmars (mW/cm2) Max |
TES (mW/cm2) Max |
Sanwa (mmW) Max |
Sanwa (mmW) Min |
|---|---|---|---|---|
| ReGen Q8 | 70.6 | 69.8 | 23.28 | 19.46 (84% of Max) |
| Comp N | 52.4 | 45.31 | 19.53 | 9.05 *1 (46% of Max) |
| Comp 360 | 13.2 | 11.9.2 | 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.
*We have used these systems to test systems at a trade show and found some pods were reading less than 2 mW/cm2. We were blown away that anyone would buy a pod with that power density at any price.
| Light Pod | Tenmars (%)
Maximum | TES (%)
Maximum | Sanwa (%)
Maximum | Average of
All Meters (%) |
|---|---|---|---|---|
| ReGen Q8 vs NT | 35% Increase | 54% Increase | 19% Increase | 36% Increase |
| ReGen Q8 vs TL360 | 535% Increase | 586% Increase | 548% Increase | 556% Increase |
