Reproducability
•
0 likes•66 views
This document discusses the importance of fully and accurately reporting parameters in photobiomodulation research to ensure reproducibility. It notes that parameters are often incompletely reported or chosen arbitrarily rather than being based on previous studies. This makes it difficult to replicate studies or perform meta-analyses. The document recommends including all relevant parameters in a standardized tabular format and provides an example of how parameters could be comprehensively summarized in an abstract. Proper reporting of parameters is necessary to advance the field of photobiomodulation research.
![parameters. Jenkins and Carroll4
proposed a tabular format
for reporting parameters in a clear, concise, comprehensive,
and standardized manner.
Tables 1–3 show the work of some fictional authors,
Smith et al., who use the tabular method to include neces-
sary detail for their treatment of carpal tunnel syndrome.
Although the inclusion of all these parameters would sig-
nificantly improve the quality of research, the complexity of the
light parameters often requires the inclusion of details such as
the polarization, shape, profile, and divergence of the beam, and
– for switched/pulsed beams – the frequency, pulse duration,
duty cycle, and waveform. Such details should be available to
authors from the equipment manufacturer or as a product of in-
house and/or independent measurement and testing.
In the Abstract to their article, our fictional authors Smith
et al. write that ‘‘.an 810 nm, 100 mW continuous wave laser,
spot size 0.5 cm2
, was placed in contact with the skin and firm
pressure applied. Three points over the transverse carpal lig-
ament were irradiated for 40 sec each, delivering 4 J (8J/cm2
)
per point, for a total energy of 12J per session. Laser irradi-
ation was performed oncedaily for 5 days, with the total energy
delivered being 60 J.’’ This is quite a comprehensive summary
of the important parameters, and – although not a complete list
– practically sufficient withinitselftoallow the laser irradiation
aspect of this study to be accurately reproduced.
At the very least, these are the parameters that should be
included in the Abstract. The majority of readers of a study
actually only read the PubMed abstract, and abstracts with
incorrect or omitted parameters can be misleading. The cre-
ation of ‘‘PubMed Commons’’ offers an opportunity for re-
searchers and readers to add pertinent information about
studies being incomplete or flawed; however, we should not
rely on this to remedy such fundamental errors and omissions.
Being meticulous about the reporting of light parameters is
mandatory but not sufficient. When information about pre-
vious studies in the area, in the Introduction and the Dis-
cussion, is added, readers are often left in the dark. With the
great variation in the possible combinations of light param-
eters, apples and bananas are too frequently compared. Our
suggestion is to include the most important parameters when
referring to other studies. For example, Jones et al. (810nm,
100 mW, 3 points ·4 J [8J/cm2
] per point, 12J total, 1· daily
·5 days). Such writing will make it possible for a reader to
understand the relevance of the reference in its context.
On the subject of references, we can see room for im-
provement. References of very old articles can be justified as
historical references. However, with *20 PBM articles in
PubMed in 2000 and 4200 in 2016, it is obvious that literature
reviews and meta-analyses from the 1990s are less relevant.
Finally, there must be an end to the nomenclature con-
fusion. The topic has been discussed in this journal before,5
and the implementation of a common nomenclature is im-
portant for ‘‘outsiders’’ to understand what we are talking
about.
PBM has been used for >50 years, and no serious side
effects have been reported. In a decade when side effects of
pharmaceuticals are alarming and antibiotic resistance is a
threat, this treatment modality appears to be much needed in
the medical armamentarium, but first the scientific strength
needs to be increased, and this can only occur if the basic
use and reporting of light parameters are improved.
References
1. McNutt M. Journals unite for reproducibility. Science 2014;
346:679–679.
2. Brosseau L, Wells G, Marchand S, et al. Randomized con-
trolled trial on low level laser therapy (LLLT) in the treat-
ment of osteoarthritis (OA) of the hand. Lasers Surg Med
2005;36:210–219.
3. Roberts DB, Kruse RJ, Stoll SF. The effectiveness of ther-
apeutic Class IV (10 W) laser treatment for epicondylitis.
Lasers Surg Med 2013;45:311–317.
4. Jenkins PA, Carroll JD. How to report low-level laser ther-
apy (LLLT)/photomedicine dose and beam parameters in
clinical and laboratory studies. Photomed Laser Surg 2011;
29:785–787.
5. Anders JJ, Lanzafame RJ, Arany PR. Low-level light/laser
therapy versus photobiomodulation therapy. Photomed Laser
Surg 2015;33:183–184.
Address correspondence to:
Jan Tune´r
Sollentunavagen 172
19148 Sollentuna
Sweden
E-mail: jan.tuner@swipnet.se
Table 3. Treatment Parameters
Parameter (unit) Value Additional notes
Beam spot size at target (cm2
) 0.5
Irradiance at target (mW/cm2
) 200
Exposure duration (sec) 40 Per point
Radiant exposure (J/cm2
) 8 Per point
Radiant energy (J) 4 Per point
Number of points irradiated 3 Transverse carpal ligament, 1· directly over
median nerve, and 1· each on the ulnar
and radial sides of the median nerve.
Area irradiated (cm2
) 0.5 · 3 points Total area covered per session is 1.5 cm2
Application technique Skin contact Firm pressure applied
Number and frequency of
treatment sessions
1· daily for 5 days
Total radiant energy (J) 12/day (60 total)
92 TUNE´ R AND JENKINS](https://image.slidesharecdn.com/a0949b73-602f-4816-a16a-030f135cd1a2-161005135519/85/Reproducability-2-320.jpg)
Reproducability
- 1. Guest Editorial Parameter Reproducibility in Photobiomodulation Jan Tune´r, DDS,1 and Peter A. Jenkins, MBA2 Reproducibility is a key factor in science.1 A single medical scientific result is not enough for reliability; it takes at least another identical study with the same outcome to make the claims credible. A major problem in photo- biomodulation (PBM) is the lack of proper reporting of the in- volved parameters and, further to that, the control of the parameters. Too often, the reporting of the parameters used in a study is incomplete, and the use of specific parameters is ad hoc. Parameters seem to be those of the equipment at hand, rather than being chosen specifically to, for example, replicate those used in a previous study or fall within an already-known effec- tive range applicable to current work. This lack of quality control among too many researchers and scientific journals creates an obstacle in finding reproducibility in meta-analyses. Frequently, such efforts end up with the conclusion that no definite conclu- sion can be made, because of the great variety in the reported parameters, no matter how many positive studies there are. Researchers do not have to stick to parameters used in other studies; they are free and encouraged to explore all the available parameters within the supposed therapeutic win- dow. Without a full and correct reporting of all pertinent light source parameters, however, nobody can perform a control study even of the best studies. What is needed is a close cooperation between researchers and journals. The definition of light parameters is only basic physics, and no guesswork is required. However, researchers in the PBM field generally come from professions for which physics has not been on the curriculum. Although they are very qualified in their own professional field, they may lack understanding of PBM. Our suggestion is to include a physicist on the team to make sure that the actual ‘‘medicine’’ to be tested is not flawed before the study even has begun. The majority of submitted articles have to undergo one or several revisions before being accepted; however, often the parameters are still incorrect or incomplete upon publication. Therefore, solving the problem requires vigilance and action at multiple levels. Reviewers must assess the reported pa- rameters and request revision where they do not meet the requirements of the journal; and journal editors and staff must ensure that only articles that meet their stated standards are published. And it is important not to forget the obligation of manufacturers to report the parameters of their devices ac- curately and honestly, and to refrain from highlighting factors that sound good in marketing materials but that lend little to the utility of the device and/or reproducibility of outcomes. Ultimately, however, it is the author who is charged with the fundamental responsibility, to first obtain and then report an accurate and complete set of parameters, thus ensuring that the work may be reproduced and, therefore, add to the overall body of knowledge. In other words, it is the author’s re- sponsibility to produce good science. The most flawed parameters are the energy (J) and the dose (J/cm2 ). Too often, only one of them is reported, but both need to be within the so-called therapeutic window. A seemingly reasonable dose may just be the effect of a thin fiber,2 and a high energy may be dispersed over a large area, thus resulting in a low dose.3 Qualified readers of an article may be able to calculate what is missing if other parameters such as the spot size (cm2 ) is reported. However, anyone should be able to have access to all the necessary Table 1. Device Information Manufacturer XYZ Co. Model XYZ-810 Year produced 2016 Number of emitters 1 Emitter type Laser diode GaAlAs Beam delivery Emitter mounted in hand-held probe with beam-correction optics and convex glass lens Table 2. Irradiation Parameters Parameter (unit) Value Measurement method or information source Center wavelength (nm) 810 Manufacturer’s specification Spectral bandwidth (nm) –3 Manufacturer’s specification Operating mode Continuous Wave Manufacturer’s specification Radiant power (mW) 100 Independent testing Aperture diameter (cm) 0.8 Manufacturer’s specification Irradiance at aperture (mW/cm2 ) 200 Independent testing 1 Private dental clinic, Grangesberg, Sweden. 2 SpectraVET, Inc., Education & Technology, Lanwdale, North Carolina. Photomedicine and Laser Surgery Volume 34, Number 3, 2016 ª Mary Ann Liebert, Inc. Pp. 91–92 DOI: 10.1089/pho.2016.4105 91
- 2. parameters. Jenkins and Carroll4 proposed a tabular format for reporting parameters in a clear, concise, comprehensive, and standardized manner. Tables 1–3 show the work of some fictional authors, Smith et al., who use the tabular method to include neces- sary detail for their treatment of carpal tunnel syndrome. Although the inclusion of all these parameters would sig- nificantly improve the quality of research, the complexity of the light parameters often requires the inclusion of details such as the polarization, shape, profile, and divergence of the beam, and – for switched/pulsed beams – the frequency, pulse duration, duty cycle, and waveform. Such details should be available to authors from the equipment manufacturer or as a product of in- house and/or independent measurement and testing. In the Abstract to their article, our fictional authors Smith et al. write that ‘‘.an 810 nm, 100 mW continuous wave laser, spot size 0.5 cm2 , was placed in contact with the skin and firm pressure applied. Three points over the transverse carpal lig- ament were irradiated for 40 sec each, delivering 4 J (8J/cm2 ) per point, for a total energy of 12J per session. Laser irradi- ation was performed oncedaily for 5 days, with the total energy delivered being 60 J.’’ This is quite a comprehensive summary of the important parameters, and – although not a complete list – practically sufficient withinitselftoallow the laser irradiation aspect of this study to be accurately reproduced. At the very least, these are the parameters that should be included in the Abstract. The majority of readers of a study actually only read the PubMed abstract, and abstracts with incorrect or omitted parameters can be misleading. The cre- ation of ‘‘PubMed Commons’’ offers an opportunity for re- searchers and readers to add pertinent information about studies being incomplete or flawed; however, we should not rely on this to remedy such fundamental errors and omissions. Being meticulous about the reporting of light parameters is mandatory but not sufficient. When information about pre- vious studies in the area, in the Introduction and the Dis- cussion, is added, readers are often left in the dark. With the great variation in the possible combinations of light param- eters, apples and bananas are too frequently compared. Our suggestion is to include the most important parameters when referring to other studies. For example, Jones et al. (810nm, 100 mW, 3 points ·4 J [8J/cm2 ] per point, 12J total, 1· daily ·5 days). Such writing will make it possible for a reader to understand the relevance of the reference in its context. On the subject of references, we can see room for im- provement. References of very old articles can be justified as historical references. However, with *20 PBM articles in PubMed in 2000 and 4200 in 2016, it is obvious that literature reviews and meta-analyses from the 1990s are less relevant. Finally, there must be an end to the nomenclature con- fusion. The topic has been discussed in this journal before,5 and the implementation of a common nomenclature is im- portant for ‘‘outsiders’’ to understand what we are talking about. PBM has been used for >50 years, and no serious side effects have been reported. In a decade when side effects of pharmaceuticals are alarming and antibiotic resistance is a threat, this treatment modality appears to be much needed in the medical armamentarium, but first the scientific strength needs to be increased, and this can only occur if the basic use and reporting of light parameters are improved. References 1. McNutt M. Journals unite for reproducibility. Science 2014; 346:679–679. 2. Brosseau L, Wells G, Marchand S, et al. Randomized con- trolled trial on low level laser therapy (LLLT) in the treat- ment of osteoarthritis (OA) of the hand. Lasers Surg Med 2005;36:210–219. 3. Roberts DB, Kruse RJ, Stoll SF. The effectiveness of ther- apeutic Class IV (10 W) laser treatment for epicondylitis. Lasers Surg Med 2013;45:311–317. 4. Jenkins PA, Carroll JD. How to report low-level laser ther- apy (LLLT)/photomedicine dose and beam parameters in clinical and laboratory studies. Photomed Laser Surg 2011; 29:785–787. 5. Anders JJ, Lanzafame RJ, Arany PR. Low-level light/laser therapy versus photobiomodulation therapy. Photomed Laser Surg 2015;33:183–184. Address correspondence to: Jan Tune´r Sollentunavagen 172 19148 Sollentuna Sweden E-mail: jan.tuner@swipnet.se Table 3. Treatment Parameters Parameter (unit) Value Additional notes Beam spot size at target (cm2 ) 0.5 Irradiance at target (mW/cm2 ) 200 Exposure duration (sec) 40 Per point Radiant exposure (J/cm2 ) 8 Per point Radiant energy (J) 4 Per point Number of points irradiated 3 Transverse carpal ligament, 1· directly over median nerve, and 1· each on the ulnar and radial sides of the median nerve. Area irradiated (cm2 ) 0.5 · 3 points Total area covered per session is 1.5 cm2 Application technique Skin contact Firm pressure applied Number and frequency of treatment sessions 1· daily for 5 days Total radiant energy (J) 12/day (60 total) 92 TUNE´ R AND JENKINS