A Measurement System for Quasi-Spectral Determination of Absorption and Scattering Parameters of Veterinary Tissue Phantoms
Round 1
Reviewer 1 Report
The manuscript presents an optical method for measuring optical properties of phantoms. The manuscript is well written and easy to read. The system is used as a characterization tool for phantoms, which are intended to be relevant in veterinary sciences.
This paper remains me of a proceedings article using speckle patterns where tissues (healthy, burned) are characterized in time; this article is worth to be considered as a reference here [Proc. SPIE vol. 9660, 96601U (2015)]. In addition, it would be nice to extend the introduction and mention other optical methods employed for tissue/phantom characterization. See, for example, Opt. Lett. 32 (19), 2798-2800 (2007).
The description of the setup and the methodology lack of precise data, which is necessary to reproduce the experiment exposed. The models of the lasers used must be included in lines 84-86. Also, what do you mean by laser pointer? Is it a laser diode? Also provide the injection currents or the voltage used to drive these lasers. Did you incorporate any additional component to guarantee stable laser radiation? I’m afraid that this might have an impact on the measurements. Please provide details and reflect this in your manuscript text.
The sentence in line 87 needs a reference.
In the caption of Fig. 1, you refer to the sample port. What’s its size? Is the aperture adjustable?
You state in line 98 that using a breadboard ensures stability to your measurement. However, it is evident from Fig. 2 that your setup is not isolated from external vibrations. How did that impact your measurements? Normally breadboards are settled on pressure-regulated systems to isolate experiments from perturbations. If this is not the case of your experiments, how did you control your characterization experiments?
It would be useful to provide or cite the intrinsic spectrums for absorption and scatting of the ink used in the phantoms shown in Fig. 3. The authors need to be more quantitative there. Small and substantial ink addition are not very representative for the experiments. Also, the discussion of the results in lines 151-161 merit a deeper understanding of the execution of the experiments.
English is globally correct, just some minor remarks like including ‘the’ before ‘construction’ in line 14 and ‘scheme’ instead of ‘schema’ in line 91.
This paper can be revised and re-reviewed before a final decision can be reached. I recommend addressing major corrections. This reviewer will be available to assess a future revised version should the editor consider a new round is necessary.
Author Response
List of changes
Manuscript ID: applsci-446900
Title: The measurement system for quasi-spectral determination of absorption and scattering parameters of veterinary tissues phantoms
Authors: Paulina Listewnik*, Michał Wąsowicz*, Monika Kosowska, Adam Mazikowski
Journal: Applied Sciences
Special Issue: Advances of Biomedical Optics—The 15th International Conference on Laser Applications in Life Sciences (LALS 2018)
Dear Tamia Qing,
authors acknowledge the Reviewer for careful reading of the manuscript, and for their valuable comments and suggestions. Authors accepted all comments made by the Reviewer. A major revision of the manuscript has been performed. Below, there is presented a detailed list of changes introduced into the text in response to particular points raised by the Reviewer.
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REVIEWER 1:
1. This paper remains me of a proceedings article using speckle patterns where tissues (healthy, burned) are characterized in time; this article is worth to be considered as a reference here [Proc. SPIE vol. 9660, 96601U (2015)]. In addition, it would be nice to extend the introduction and mention other optical methods employed for tissue/phantom characterization. See, for example, Opt. Lett. 32 (19), 2798-2800 (2007).
Answer: Thank you for this comment.
Action: The text has been changed as follows:
“Understanding the interaction between light and matter is crucial while developing light-based technologies, especially, for applications in medicine. Thus, research groups are employing various optical methods for tissues and tissue phantoms characterization. The dynamic laser speckle technique was used for the evaluation of tissues viability, by performing ex vivo measurements on healthy and burned skin tissue [14]. The optical properties of skin microcirculation phantom were investigated by the means of Laser Doppler flowmetry utilizing self-mixing interferometry which allowed for obtaining flow maps [15]. The diffuse optical tomography combined with the utilization of optomechanical technique allowed for accurate detection of pathological changes mimicked by a phantom [16]. “
“The determination of absorption and scattering coefficients can be performed with the measurement setup using frequency domain near-infrared spectroscopy [18], the frequency domain imaging system [19] or the broadband spectroscopy setup [20]. Goniometric methods [21] or utilization of integrating spheres [22–24] are also commonly used.”
The following references were added:
14. Ramírez-Miquet, E.E.; Romero, L.M.M.; Darias, J.G.; Martínez-Celorio, R.A. Ex-vivo assessment of tissue viability using dynamic laser speckle. In Proceedings of the SPECKLE 2015: VI International Conference on Speckle Metrology; International Society for Optics and Photonics, 2015; Vol. 9660, p. 96601U.
15. Zakian, C.; Dickinson, M. Laser Doppler imaging through tissues phantoms by using self-mixing interferometry with a laser diode. Opt. Lett., OL 2007, 32, 2798–2800.
18. Sthalekar, C.C.; Miao, Y.; Koomson, V.J. Optical Characterization of Tissue Phantoms Using a Silicon Integrated fdNIRS System on Chip. IEEE Transactions on Biomedical Circuits and Systems 2017, 11, 279–286.
19. Monte, A.F.G.; Reis, A.F.; Junior, L.B.C.; Antunes, A. Preparation and quantitative characterization of polydimethylsiloxane optical phantoms with zinc-phthalocyanine dye absorbers. Appl. Opt., AO 2018, 57, 5865–5871.
20. Shahin, A.; Bachir, W. Broadband spectroscopy for characterization of tissue-like phantom optical properties. Polish Journal of Medical Physics and Engineering 2017, 23, 121–126.
2. The description of the setup and the methodology lack of precise data, which is necessary to reproduce the experiment exposed. The models of the lasers used must be included in lines 84-86. Also, what do you mean by laser pointer? Is it a laser diode? Also provide the injection currents or the voltage used to drive these lasers. Did you incorporate any additional component to guarantee stable laser radiation? I’m afraid that this might have an impact on the measurements. Please provide details and reflect this in your manuscript text.
Answer: Thank you for this comment.
Action: The text has been changed as follows:
“The measurement system was constructed using 4P-GPS-053-SL (Labsphere Inc, North Sutton, NH, USA) integrating sphere. The internal diameter of the sphere is 5.3 in. (13.46 cm), while the sample port diameter is 1 in. (2,54 cm) [27]. The sphere utilizes Spectralon® coating providing a highly reflective surface – the diffuse reflection coefficient of above 99% for wavelengths from 400 nm to 1500 nm. Red, green and blue laser modules from Roithner Lasertechnik (Vienna, Austria) were used as the light sources during investigation: red laser diode module with a wavelength of 635 nm (LDM635-03-08X25), green DPSS laser diode module, operating on second-harmonic, with a wavelength of 532 nm (CW532-5-831) and blue laser pointer with a wavelength of 447 nm (GLP-447-20). These laser sources were supplied by voltage of 3 V (red), 3.3 V (green) and 4.7 V (blue), respectively. To ensure power stability of the standard blue laser pointer 2x3V CR2 battery power supply was replaced by laboratory power supply and the voltage was reduced to 4.7 V.
All the light sources utilized during the examination are of wavelengths from visible spectral range [28]. They are also used for the animal treatment in veterinary medicine. In order to ensure accuracy and repeatability of performed measurements, luxmeter L-100 with dedicated measuring head by Sonopan (Białystok, Poland) is used as a detector. Measuring head of a luxmeter has Lambertian input characteristic. White calibration Plate CS-A21 by Konica Minolta (Tokyo, Japan) was used as a reflection standard (reflection coefficient - 96,9%) [29]. “
“Determination of scattering and absorption coefficients of a sample is based on relative measurements (absolute output is not very significant, provided it is in the range of detector sensitivity). However, before performing measurements, each source was turned on for approximately 30 min (45 min in case of the blue source) for stabilization of thermal condition, and the room temperature was stabilized to 23°C with an accuracy of 1°C. Additionally, the aforementioned quick change between configurations allows for taking measurements within short time (1-2 min), which is the key factor for relative measurements. “
3. The sentence in line 87 needs a reference.
Answer: Thank you for this comment.
Action: The reference has been added.
28. Wagnières, G.; Cheng, S.; Zellweger, M.; Utke, N.; Braichotte, D.; Ballini, J.P.; van den Bergh, H. An optical phantom with tissue-like properties in the visible for use in PDT and fluorescence spectroscopy. Phys Med Biol 1997, 42, 1415–1426.
4. In the caption of Fig. 1, you refer to the sample port. What’s its size? Is the aperture adjustable?
Answer: Thank you for this comment. The sample port diameter is 1 in. (2,54 cm). The required information was added to the manuscript. The aperture itself is not adjustable, however, it is easily replaceable. The additional aperture of a different size can be prepared and applied, therefore changing the default diameter of the port.
Action: The text has been changed as follows:
“The measurement system was constructed using 4P-GPS-053-SL (Labsphere Inc, North Sutton, NH, USA) integrating sphere. The internal diameter of the sphere is 5.3 in. (13.46 cm), while the sample port diameter is 1 in. (2,54 cm) [27]. “
5. You state in line 98 that using a breadboard ensures stability to your measurement. However, it is evident from Fig. 2 that your setup is not isolated from external vibrations. How did that impact your measurements? Normally breadboards are settled on pressure-regulated systems to isolate experiments from perturbations. If this is not the case of your experiments, how did you control your characterization experiments?
Answer: Thank you for this comment. Optical breadboard with dimensions of 15x60x1.27 cm was used in order to provide mechanical stability and fixed layout of mechanical components. Utilization of an optical breadboard also allowed to implement movement of the sphere around its axis, which in turn enables quick shift between configurations (reflective and transmissive).
Acquired knowledge and experience of the authors indicate isolation from external vibrations is not a crucial issue. The size of the samples used during experiments is big (Ø=45 mm) as well as the size of the sample port (Ø=25.4 mm). The diameter of a laser beam is over 10 times smaller (1-2 mm) than the diameter of the sample port, therefore any possible defects of the sample structure can be averaged. Because strong vibrations were not detected, in the authors’ opinion, all potential vibrations will be inconsequential and would not influence obtained results. Mechanical stability is fully acceptable.
Action: The word “acceptable” was added to the manuscript.
6. It would be useful to provide or cite the intrinsic spectrums for absorption and scatting of the ink used in the phantoms shown in Fig. 3. The authors need to be more quantitative there. Small and substantial ink addition are not very representative for the experiments. Also, the discussion of the results in lines 151-161 merit a deeper understanding of the execution of the experiments.
Answer: Thank you for this comment. The quantities of the India ink added to the samples B and C are respectively 5 µl and 20 µl. The goal of using samples with the additional ink was to investigate the influence of the ink on the absorption coefficient µa. The default absorption coefficient of the sample, which was not modified is close to 0.
Action: The text has been changed as follows:
“Various amount of India ink was added to the two remaining samples (B, C) in order to pre-evaluate the possibility to increase absorption of these samples, as the estimated absorption of the reference sample is small, close to zero. All the samples are shown in Figure 3.
Figure 3. Produced phantoms: A – reference Ø=45 mm, d=2 mm, B – with addition of India ink (5 µl) Ø=45 mm, d=2.6 mm; C – with addition of India ink (20 µl) Ø=45 mm, d=2.3 mm.
“The measurement results for samples B and C showed a significant change in the absorption coefficient with the addition of small amounts of ink. However, further studies are planned to accurately determine quantitative ink concentration.
While maintaining due diligence, the uncertainty of measurement for the reference sample (A) has been estimated at ±0.02 for µa, and ±0.05 for µs’. The estimated uncertainty of measurement for the samples B and C are greater, mainly due to noticed non-uniformity of the thickness of these samples.”
7. English is globally correct, just some minor remarks like including ‘the’ before ‘construction’ in line 14 and ‘scheme’ instead of ‘schema’ in line 91.
Answer: Thank you for this comment.
Action: The typos have been corrected.
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I hope that the presented explanations and corrections introduced to the manuscript will be satisfactory to Reviewer and to you. Thank you again for your time and effort spent on improving our manuscript.
Please, do not hesitate to contact me in case of any doubts or questions.
Yours sincerely,
Adam Mazikowski
Author Response File: 
Author Response.doc
Reviewer 2 Report
In the manuscript ‘Measurement system for quasi-spectral determination of scattering parameters of veterinary tissue phantoms’, the authors described a system for quantifying optical parameters of phantoms. Where it is an interesting paper, I think significant improvement is needed for the manuscript before it can be accepted for publication. I suggest the authors address the following major issues.
Language use of the manuscript needs a thorough improvement.
The introduction should be re-written.
The style is not precise enough, which is not right for academic writing, the first sentence is too broad for example. ‘innovative technologies’ is a broad term. Line 40 is another example – ‘innovative technologies’.
Color of lasers is not the ideal way of summarizing applications of laser technology. If the authors insist on this, more details on the principles of each laser application should be given, rather than vague statements such as ‘those laser were also successfully used on dogs during experimental treatments of prostate’ – what kind of disease is the target? Inflammation, cancer or something else?
Be precise with scientific statements – line 48, for example, the transmittance is essentially determined be scattering and absorption coefficient – I don’t believe transmittance should be listed together as absorption. Just as the authors mentioned in line 52.
Suppliers of products used in the experiments should be provided, for example, the laser systems.
Determination of absorption and scattering coefficients are not clear, at least the equations should be briefly discussed.
When presenting the results, the authors should give uncertainties.
Author Response
List of changes
Manuscript ID: applsci-446900
Title: The measurement system for quasi-spectral determination of absorption and scattering parameters of veterinary tissues phantoms
Authors: Paulina Listewnik*, Michał Wąsowicz*, Monika Kosowska, Adam Mazikowski
Journal: Applied Sciences
Special Issue: Advances of Biomedical Optics—The 15th International Conference on Laser Applications in Life Sciences (LALS 2018)
Dear Tamia Qing,
authors acknowledge the Reviewer for careful reading of the manuscript, and for their valuable comments and suggestions. Authors accepted all comments made by the Reviewer. A major revision of the manuscript has been performed. Below, there is presented a detailed list of changes introduced into the text in response to particular points raised by the Reviewer.
===================================================================
REVIEWER 2:
1. Language use of the manuscript needs a thorough improvement.
Answer: Thank you for this comment.
Action: The manuscript has undergone a thorough English correction in respect of grammar and sentence construction, style, punctuation and typos.
2. The introduction should be re-written.
Answer: Thank you for this comment. The introduction has been re-written. The modified text has been highlighted in the manuscript
Action: The text of the introduction has been changed as follows:
“Animal treatment with the use of modern technologies utilizing light becomes increasingly popular in veterinary medicine. One of the most significant groups of therapies is laser treatment, especially low-level laser therapy (LLLT), which includes cases of treatment of open, sterile and infected wounds, acute and chronic inflammatory lesions [1,2]. To aid in the treatment of various afflictions, laser radiation from a wide range of a visible spectrum is used.
The radiation wavelength of 635 nm is used to accelerate the healing of soft tissues in acute and chronic inflammatory conditions and during postoperative treatment [2]. Lasers with an operational wavelength of 532 nm are useful in eliminating superficial vascular skin changes e.g. bruises, ecchymosis and decubitus [3] as well as the treatment of diverse pathomorphological prostatitis inflammation in the male species belonging to Canis lupus f. domestica [4–6]. Lasers with a wavelength of 447 nm, however, are used for intravascular laser biostimulation (ILB) during the treatment of bacterial and viral diseases. It was successfully used to fight hepatitis C viruses and to treat diseases caused by spirochetes, e.g. Lyme disease. To date, the assessment of the effectiveness of combining the 447 nm wavelength with photosensitization indicates even larger prospective applications of this wavelength [7]. Research regarding the visual inspection of tissues, e.g. operative field is also conducted [8].
Because veterinary medicine requires multiple ranges of the visible spectrum wavelengths to treat a variety of diseases, the paper focuses on the utilization of three wavelengths, each from a different range.
While treating tissues, preliminary examinations are performed on optical phantoms – materials mimicking selected optical parameters of tissue [9,10]. Utilization of optical phantoms, in either medicine or veterinary medicine, eliminates the necessity of upholding bioethical principles and laboratories, in which the tests are performed, do not have to comply with strict norms [11]. Optical phantoms are also very durable. Unlike real tissues, they are resistant to degradation, therefore preserving their optical parameters, which is beneficial during long-term examination of relation between light and matter [12,13].
Understanding the interaction between light and matter is crucial while developing light-based technologies, especially, for applications in medicine. Thus, research groups are employing various optical methods for tissues and tissue phantoms characterization. The dynamic laser speckle technique was used for the evaluation of tissues viability, by performing ex vivo measurements on healthy and burned skin tissue [14]. The optical properties of skin microcirculation phantom were investigated by the means of Laser Doppler flowmetry utilizing self-mixing interferometry which allowed for obtaining flow maps [15]. The diffuse optical tomography combined with the utilization of optomechanical technique allowed for accurate detection of pathological changes mimicked by a phantom [16].
Important optical parameters affecting the propagation of optical radiation in the medium are the refractive index n and the absorption coefficient µa. In case of highly scattering media, like biological matter (tissues) or their artificial equivalent (optical phantoms), very important parameters are also the scattering coefficient µs and the scattering anisotropy g or the reduced scattering coefficient µs’= µs(1–g) [17]. Knowing absorption and scattering parameters allows to analyze, model and understand phenomena occurring in the tissue during its interaction with light radiation, which is essential for medical diagnosis as well as evaluation of a laser influence on the tissue.
The determination of absorption and scattering coefficients can be performed with the measurement setup using frequency domain near-infrared spectroscopy [18], the frequency domain imaging system [19] or the broadband spectroscopy setup [20]. Goniometric methods [21] or utilization of integrating spheres [22–24] are also commonly used. Goniometric techniques allow establishing directional distribution of scattered radiation. However, for materials of a substantial thickness, directional characteristic exhibits near-Lambertian distribution due to the blurring of directional properties. Moreover, obtaining total scattered flux requires numerical integration over the entire hemisphere employing the measured directional distribution of scattered radiation.” (…)
3. The style is not precise enough, which is not right for academic writing, the first sentence is too broad for example. ‘innovative technologies’ is a broad term. Line 40 is another example – ‘innovative technologies.
Answer: Thank you for this comment. The manuscript was revised and all vague expressions were either specified or removed.
4. Color of lasers is not the ideal way of summarizing applications of laser technology. If the authors insist on this, more details on the principles of each laser application should be given, rather than vague statements such as ‘those lasers were also successfully used on dogs during experimental treatments of prostate’ – what kind of disease is the target? Inflammation, cancer or something else?
Answer: Thank you for this comment. Applications of the lasers have been summarized using representative wavelengths of each investigated range. Targeted diseases were further specified.
Action: The text has been changed as follows:
“The radiation wavelength of 635 nm is used to accelerate the healing of soft tissues in acute and chronic inflammatory conditions and during postoperative treatment [2]. Lasers with an operational wavelength of 532 nm are useful in eliminating superficial vascular skin changes e.g. bruises, ecchymosis and decubitus [3] as well as the treatment of diverse pathomorphological prostatitis inflammation in the male species belonging to Canis lupus f. domestica [4–6]. Lasers with a wavelength of 447 nm, however, are used for intravascular laser biostimulation (ILB) during the treatment of bacterial and viral diseases. It was successfully used to fight hepatitis C viruses and to treat diseases caused by spirochetes, e.g. Lyme disease. To date, the assessment of the effectiveness of combining the 447 nm wavelength with photosensitization indicates even larger prospective applications of this wavelength [7].“
“The sphere utilizes Spectralon® coating providing a highly reflective surface – the diffuse reflection coefficient of above 99% for wavelengths from 400 nm to 1500 nm. Red, green and blue laser modules from Roithner Lasertechnik (Vienna, Austria) were used as the light sources during investigation: red laser diode module with a wavelength of 635 nm (LDM635-03-08X25), green DPSS laser diode module, operating on second-harmonic, with a wavelength of 532 nm (CW532-5-831) and blue laser pointer with a wavelength of 447 nm (GLP-447-20).“
5. Be precise with scientific statements – line 48, for example, the transmittance is essentially determined be scattering and absorption coefficient – I don’t believe transmittance should be listed together as absorption. Just as the authors mentioned in line 52.
Answer: Thank you for this comment.
Action: The text has been changed as follows:
“Important optical parameters affecting the propagation of optical radiation in the medium are the refractive index n and the absorption coefficient µa. In case of highly scattering media, like biological matter (tissues) or their artificial equivalent (optical phantoms), very important parameters are also the scattering coefficient µs and the scattering anisotropy g or the reduced scattering coefficient µs’= µs(1–g) [17].“
The naming of parameters was corrected.
6. Suppliers of products used in the experiments should be provided, for example, the laser systems.
Answer: Thank you for this comment. Suppliers of all products used during this research have been provided in the manuscript.
Action: The text has been changed as follows:
“The measurement system was constructed using 4P-GPS-053-SL (Labsphere Inc, North Sutton, NH, USA) integrating sphere. The internal diameter of the sphere is 5.3 in. (13.46 cm), while the sample port diameter is 1 in. (2,54 cm) [27]. The sphere utilizes Spectralon® coating providing a highly reflective surface – the diffuse reflection coefficient of above 99% for wavelengths from 400 nm to 1500 nm. Red, green and blue laser modules from Roithner Lasertechnik (Vienna, Austria) were used as the light sources during investigation: red laser diode module with a wavelength of 635 nm (LDM635-03-08X25), green DPSS laser diode module, operating on second-harmonic, with a wavelength of 532 nm (CW532-5-831) and blue laser pointer with a wavelength of 447 nm (GLP-447-20).”
“In order to ensure accuracy and repeatability of performed measurements, luxmeter L-100 with dedicated measuring head by Sonopan (Białystok, Poland) is used as a detector. Measuring head of a luxmeter has Lambertian input characteristic. White calibration Plate CS-A21 by Konica Minolta (Tokyo, Japan) was used as a reflection standard (reflection coefficient - 96,9%) [29].“
„The integrating sphere, the light source and the luxmeter measuring head were precisely mounted on the optical breadboard (15x60 cm, Thorlabs, Newton, NJ, USA) to provide acceptable stability of the system, which allows obtaining accurate results.“
7. Determination of absorption and scattering coefficients are not clear, at least the equations should be briefly discussed.
Answer: Thank you for this comment. All the formulas of the Kubelka-Munk model, which were used during this research have been added to the manuscript.
Action: The text has been changed as follows:
“The calculated values of diffuse reflection Rd and diffuse transmission Td were used as a basis for determination of absorption coefficient µa and reduced scattering coefficient µs’ accordingly to the Kubelka-Munk model using the following formulas [26]:
(3) | |
(4) |
where SKM –Kubelka-Munk scattering coefficient, KKM – Kubelka-Munk absorption coefficient, d—sample thickness, and:
| (5) |
| (6) |
Finally, absorption coefficient µa and reduced scattering coefficient µs’ can be calculated:
| (7) |
| (8) |
8. When presenting the results, the authors should give uncertainties.
Answer: Thank you for this comment.
Action: The estimated measurement tolerance has been added in Table 1.
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I hope that the presented explanations and corrections introduced to the manuscript will be satisfactory to Reviewer and to you. Thank you again for your time and effort spent on improving our manuscript.
Please, do not hesitate to contact me in case of any doubts or questions.
Yours sincerely,
Adam Mazikowski
Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
Review report: applsci-446900-v2
March 25th, 2019
The revised version of this manuscript was nicely modified, and I find my remarks from the first-round-review well addressed. I think the paper can now be considered for publication after some minor corrections still remaining.
Check again your text in lines 101 to 107. Your text differs in the manuscript with respect to your reply letter.
Erase OL and AO from references 15 and 19 respectively. You already include the journal acronym
Also, other journal acronyms must be incorporated (should they exist) instead of using the full journal name as in ref. 20 for example. And when writing the journal acronym, please use dots (.) or not in homogeneous manner taking the predefined journal style for doing this as a model.
After these remarks are addressed the paper could be accepted should the editor and the other reviewer(s) agree
Author Response
List of changes
Manuscript ID: applsci-446900
Title: The measurement system for quasi-spectral determination of absorption and scattering parameters of veterinary tissues phantoms
Authors: Paulina Listewnik*, Michał Wąsowicz*, Monika Kosowska, Adam Mazikowski
Journal: Applied Sciences
Special Issue: Advances of Biomedical Optics—The 15th International Conference on Laser Applications in Life Sciences (LALS 2018)
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REVIEWER 1:
1. Check again your text in lines 101 to 107. Your text differs in the manuscript with respect to your reply letter.
Answer: Thank you for this comment.
Action: The discrepancy between the text in the manuscript and the reply letter occurred during assembling of the manuscript. The text included in the manuscript is the final version:
“The measurement system was constructed using 4P-GPS-053-SL (Labsphere Inc, North Sutton, NH, USA) integrating sphere. The internal diameter of the sphere is 5.3 in. (13.46 cm), while the sample port diameter is 1 in. (2,54 cm) [27]. The sphere utilizes Spectralon® coating providing a highly reflective surface – the diffuse reflection coefficient of above 99% for wavelengths from 400 nm to 1500 nm. Laser modules from Roithner Lasertechnik (Vienna, Austria) of red, green and blue radiation were used as the light sources during investigation: laser diode module with a wavelength of 635 nm (LDM635-03-08X25, red), DPSS laser diode module, operating on second-harmonic, with a wavelength of 532 nm (CW532-5-831, green) and laser pointer with a wavelength of 447 nm (GLP-447-20, blue). These laser sources were supplied by voltage of 3 V (red), 3.3 V (green) and 4.7 V (blue), respectively. To ensure power stability of the standard GLP-447-20 laser pointer 2x3V CR2 battery power supply was replaced by laboratory power supply and the voltage was reduced to 4.7 V.”
2. Erase OL and AO from references 15 and 19 respectively. You already include the journal acronym
Answer: Thank you for this comment.
Action: References 15 and 19 were corrected to avoid repetitions of the acronyms.
15. Zakian, C.; Dickinson, M. Laser Doppler imaging through tissues phantoms by using self-mixing interferometry with a laser diode. Opt. Lett. 2007, 32, 2798–2800.
19. Monte, A.F.G.; Reis, A.F.; Junior, L.B.C.; Antunes, A. Preparation and quantitative characterization of polydimethylsiloxane optical phantoms with zinc-phthalocyanine dye absorbers. Appl. Opt. 2018, 57, 5865–5871.
3. Also, other journal acronyms must be incorporated (should they exist) instead of using the full journal name as in ref. 20 for example. And when writing the journal acronym, please use dots (.) or not in homogeneous manner taking the predefined journal style for doing this as a model.
Answer: Thank you for this comment.
Action: All references were reviewed and corrected to present them in a homogenous manner.
1. Gál, P.; Mokrý, M.; Vidinský, B.; Kilík, R.; Depta, F.; Harakalová, M.; Longauer, F.; Mozes, S.; Sabo, J. Effect of equal daily doses achieved by different power densities of low-level laser therapy at 635 nm on open skin wound healing in normal and corticosteroid-treated rats. Lasers Med. Sci. 2009, 24, 539–547.
2. Vasilenko, T.; Slezák, M.; Kovác, I.; Bottková, Z.; Jakubco, J.; Kostelníková, M.; Tomori, Z.; Gál, P. The effect of equal daily dose achieved by different power densities of low-level laser therapy at 635 and 670 nm on wound tensile strength in rats: a short report. Photomed. Laser Surg. 2010, 28, 281–283.
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11. Karpienko, K.; Gnyba, M.; Milewska, D.; Wróbel, M.S.; Jędrzejewska-Szczerska, M. Blood equivalent phantom vs whole human blood, a comparative study. J. Innov. Opt. Health Sci. 2015, 09, 1650012.
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I hope that the presented explanations and corrections introduced to the manuscript will be satisfactory. Thank you again for your time and effort spent on improving our manuscript.
Please, do not hesitate to contact me in case of any doubts or questions.
Yours sincerely,
Adam Mazikowski
Author Response File: Author Response.doc
Reviewer 2 Report
The authors have addressed previous concerns and questions.
Author Response
Thank you for your comments. The authors appreciate your effort to improve our paper.
Sincerely,
Adam Mazikowski
