Books and peer-reviewed journal papers

1.     J.Spigulis. “Ultra-narrowband multispectral imaging. Techniques and applications”, 97 p. CRC Press / Taylor & Francis, Boca Raton, USA (2024).

https://doi.org/10.1201/9781003476702.

  1. J.Spigulis, U.Rubins, E.Kviesis-Kipge, I.Saknite, I.Oshina, E.Vasilisina, “Triple spectral line imaging of whole-body human skin: equipment, image processing, and clinical data”, Sensors 24, 7348 (2024). DOI:10.3390/s24227348. https://www.mdpi.com/1424-8220/24/22/7348.
  2. U.Rubīns, A.K.Krieviņa, K.Peksis, J.Spīgulis, “Endoscopic colour analysis of nasal mucosa: methodology and clinical data”, Proc.Latv.Acad.Sci., Sec.B, 78(3), pp.185-190 (2024). https://doi.org/10.2478/prolas-2024-0026.
  3. I.Saknite, S.Kwun, K.Zhang, A.Hood, F.Chen, L.Kangas, P.Kortteisto, A.Kukkonen, J.Spigulis, E.R.Tkaczyk, “Hyperspectral imaging to accurately segment skin erythema and hyperpigmentation in cutaneous chronic graft-versus-host disease,” J.Biophot. e202300009 (2023). DOI: 10.1002/jbio.202300009.
  4. I.Oshina, J.Spigulis, I.Kuzmina, L.Dambite, A.Berzina, “Three-dimensional representation of triple spectral line imaging data as an option for noncontact skin diagnostics”, J.Biomed.Opt. 27(9), 095005 (2022). doi: 10.1117/1.JBO.27.9.095005.
  5. I.Kuzmina, I.Oshina, L.Dambite, V.Lukinsone, A.Maslobojeva, A.Berzina, J.Spigulis, “Skin chromophore mapping by smartphone RGB camera under spectral band and spectral line illumination”, J.Biomed.Opt. 27(2), 026004 (2022). doi: 10.1117/1.JBO.27.2.026004.
  6. T.Fisher,…, I.Oshina,…, J.Spigulis, et.al, “Profiling and imaging of forensic evidence – a pan-European forensic round robin study part 1: Document forgery”, Science & Justice 62(4), p. 433-447 (2022). https://doi.org/10.1016/j.scijus.2022.06.001.

8.     I.Oshina, J.Spigulis, “Beer-Lambert law for optical tissue diagnostics: current state of the art and the main limitations”, J.Biomed.Opt. 26(10), 100901 (2021). https://doi.org/10.1117/1.JBO.26.10.100901.

9.     J.Spigulis, V.Lukinsone, I.Oshina, E.Kviesis-Kipge, M.Tamosiunas, A.Lihachev, "Riga Group’s recent results on laser applications for skin diagnostics", J.Phys.: Conf. Ser. 1859, 012033 (2021); https://iopscience.iop.org/article/10.1088/1742-6596/1859/1/012033.

10. J.Spigulis, Z.Rupenheits, U.Rubins, M.Mileiko, I.Oshina, “Spectral line reflectance and fluorescence imaging device for skin diagnostics”, Appl. Sci. 10, 7472 (2020); https://www.mdpi.com/2076-3417/10/21/7472..

  1. V.Lukinsone, A.Maslobojeva, U.Rubins,  M.Kuzminskis, M.Osis, J.Spigulis, “Remitted photon path lengths in human skin:  in-vivo measurement data”, Biomed.Opt.Expr. 11(5), 2866-2873 (2020). https://doi.org/10.1364/BOE.388349.
  2. “Biophotonics—Riga 2020”, SPIE Proceedings, vol.11585 (2020). Editor: Janis Spigulis. 

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11585.toc.

  1. M.Tamošiūnas, E.V.Plorina, M.Lange, A.Derjabo, I.Kuzmina, D.Bļizņuks, J.Spigulis, “Autofluorescence imaging for recurrence detection in skin cancer post-operative scars”, J.Biophoton. 13(3),  e201900162 (2020).  https://doi.org/10.1002/jbio.201900162 .
  2. M.Osis, V.Lukinsone, J.Latvels, I.Kuzmina, U.Rubins, J.Spigulis, “Skin remittance kinetics at the spectral range 550-790 nm”, Quant.Electr., 49(1), 2–5 (2019).
  3. B.Cugmas, E.Šturc, J.Spigulis, "Photoplethysmography in dogs and cats: a selection of alternative measurement sites for pet monitor", Physiol.Measurment, 40(1), 01NT02 (2019).

16. J.Spigulis, “Multispectral, fluorescent and photoplethysmographic imaging for remote skin assessment” – in: Optical Methods in Sensing and Imaging for Medical and Biological Applications, Ed. D.Indjin, Ž.Cveič, M.Jedrzejewska-Szsczerska (2019). ISBN 978-3-03897-371-3, mdpi.com/books/pdfview/book/1107.

  1. A.Lihachev, l.Lihacova, E.V.Plorina, M.Lange, A.Derjabo, J.Spigulis, Differentiation of seborrheic keratosis from basal cell carcinoma, nevi and melanoma by RGB autofluorescence imaging, Biomed.Opt. Express, 9(4),1852-1858 (2018).
  2. J.Spigulis, Multispectral, fluorescent and photoplethysmographic imaging for remote skin assessment, Sensors, 17, 1165 (2017).
  3. J.Spigulis, I.Oshina, A.Berzina, A.Bykov, Smartphone snapshot mapping of skin chromophores under triple-wavelength laser illumination, J.Biomed.Opt., 22(9), 091508 (2017).
  4. “Biophotonics—Riga 2017”, SPIE Proceedings, vol.10592 (2018). Editor: Janis Spigulis. 

https://spie.org/Publications/Proceedings/Volume/10592.

  1. I.Saknite, A.Zavorins, I.Zablocka, J.Kisis, J.Spigulis, Comparison of a near-infrared reflectance spectroscopy system and skin conductance measurements for in vivo estimation of skin hydration: a clinical study, J.Biomed.Photon.Engin., 3(1), 010310 (2017).
  2. J.Spigulis. “In vivo skin imaging prototypes “made in Latvia””, Front. Optoelectron., 1–12,  https://doi.org/10.1007/s12200-017-0717-5 (2017).
  3. I.Saknite, A.Zavorins, D.Jakovels, J.Spigulis, J.Kisis. Comparison of single-spot technique and RGB imaging for erythema index estimation. Physiol.Meas., 37(3), 333-346 (2016).
  4. J.Spigulis, I.Oshina. Snapshot RGB mapping of skin melanin and hemoglobin. J.Biomed. Opt, 20(5), 050503 (2015).
  5. A.Lihachev, A.Derjabo, I.Ferulova, M.Lange, I.Lihacova, J.Spigulis. Autofluorescence imaging of Basal Cell Carcinoma by smartphone RGB camera. J.Biomed.Opt., 20(12), 120502 (2015).
  6. I.Kuzmina, M.Lacis, J.Spigulis, A.Berzina, L.Valaine. Study of smartphone suitability for mapping of skin chromophores. J.Biomed.Opt., 20(9), 090503, 2015.
  7. I.Ferulova, A.Lihachev, J.Spigulis. Photobleaching effects on in-vivo skin autofluorescence lifetime. J.Biomed.Opt., 20(5), 051031 (2015).
  8. Lihachev, I. Ferulova, K. Vasiljeva, J. Spigulis. Investigation of in-vivo skin autofluorescence lifetimes under long-term cw optical excitation. Quant.Electr., 44 (8), 770-773 (2014).
  9. “Eighth International Conference on Advanced Optical Materials and Devices (AOMD-8)”, SPIE Proceedings, vol.9421 (2014). Editor: Janis Spigulis. 

https://spie.org/Publications/Proceedings/Volume/9421

  1. J.Spigulis, U.Rubins, E.Kviesis-Kipge, O.Rubenis. SkImager: a concept device for in-vivo skin assessment by multimodal imaging. Proc.Est.Acad.Sci., 63(3), 213-220 (2014).
  2. A.Silapetere, I.Saknite, J.Spigulis. Development and experimental study of phantoms for mapping skin chromophores. Latv.J.Phys.Techn. Sci., 51 (3), 58-66 (2014).
  3. U.Rubins, J.Zaharans, I.Lihacova, J.Spigulis. Multispectral video-microscope modified for skin diagnostics. Latv.J.Phys.Techn.Sci., 51(5), 65-70 (2014).
  4. D.Jakovels, I.Kuzmina, A.Berzina, L.Valeine, J.Spigulis. Noncontact monitoring of vascular lesion phototherapy efficiency by RGB multispectral imaging. J.Biomed.Opt., v.18, No.12,126019 (2013).
  5. “Biophotonics—Riga 2013”, SPIE Proceedings, vol. 9032 (2013). Editors: Janis Spigulis and Ilona Kuzmina. https://spie.org/Publications/Proceedings/Volume/9032.
  6. I.Diebele, I.Kuzmina, A.Lihachev, J.Spigulis, J.Kapostinsh, A.Derjabo, L.Valaine. Clinical evaluation of melanomas and common nevi by spectral imaging, Biomed.Opt.Express,v.3, No.3, pp. 467-472, 2012.
  7. J.Spigulis. Biophotonic technologies for noninvasive assessment of skin condition and blood microcirculation. Latv.J.Phys.Techn.Sci., v.49, No.5, pp.63-80 (2012).
  8. A.Bekina, I.Diebele, U.Rubins, J.Zaharans, A.Derjabo, J.Spigulis. Multispectral assessment of skin malformations by modified video-microscope. Latv.J.Phys.Techn.Sci., v.49, No.5, pp.4-8 (2012).
  9. D.Jakovels, J.Spigulis. RGB imaging device for mapping and monitoring of hemoglobin distribution in skin. Lith. J.Phys., v.52, No.1, pp. 50-54 (2012).
  10. L.Asare, E.Kviesis-Kipge, M.Ozols, J.Spigulis, R.Erts. Multi-spectral Optoelectronic Device for Skin Microcirculation Analysis. Lith. J.Phys., v.52, No.1, pp. 59-62 (2012).
  11. I.Ferulova, A.Rieba, J.Lesins, A.Berzina, A.Lihachev, J.Spigulis. Portable device for skin autofluorescence photobleaching measurements. Lith. J.Phys., v.52, No.1, pp. 55-58 (2012).
  12. I.Kuzmina, I. Diebele, D. Jakovels, J.Spigulis, L..Valeine, J. Kapostinsh. Towards noncontact skin melanoma selection by multispectral imaging analysis, J. Biomed. Opt., v.16, No.6, 060502 (2011).
  13. I.Kuzmina, I.Diebele, J.Spigulis, L.Valeine, A.Kempele, A.Abelite. Contact and contactless diffuse reflectance spectroscopy: potential for recovery monitoring of vascular lesions after intense pulsed light treatment, J. Biomed. Opt., v. 16, No.4, 040505 (2011).
  14. Saknite, D. Jakovels, J. Spigulis. Distant determination of bilirubin distribution in skin by multi-spectral imaging. Latv.J.Phys.Tech.Sci., No.2, p.50-55 (2011).
  15. Lihachev, J. Lesins, D. Jakovels, J. Spigulis. Low power cw-laser signatures on human skin, Quant. Electr., v. 40, No.12, 1077-1080 (2010).
  16. D. Jakovels and J. Spigulis, 2-D mapping of skin chromophores in the spectral range 500-700 nm, J. Biophoton. v.3, No. 3, pp. 125–129 (2010).
  17. R. Erts, E. Kviesis-Kipge, J. Zaharans, E. Zaharans, J. Spigulis. Wireless photoplethysmography finger sensor probe, IEEE Explore, 10.1109/BEC.2010.5630194, p. 283-284 (2010).
  18. Spigulis, A. Lihachev, and R. Erts, Imaging of laser-excited tissue autofluorescence bleaching rates, Appl. Opt., v. 48, No. 10, pp. D163-D168 (2009).
  19. “14th Nordic-Baltic Conference on Biomedical Engineering and Medical Physics”,  IFMBE Proceedings, vol. 20, Springer (2008), Edittors: Alexey Katashev, Yuri Dekhtyar and Janis Spigulis. 

https://www.springer.com/gp/book/9783540693666#aboutBook

  1. Gailite, J. Spigulis, A. Lihachev. Multilaser photoplethysmography technique. Las. Med. Sci., v. 23, pp. 189-193 (2008).
  2. “Sixth International Conference on Advanced Optical Materials and Devices (AOMD-6)” (2008), SPIE Proceedings vol. 7142, Editors: Janis Spigulis, Andris Krumins, Donats Millers, Andris Sternberg, Inta Muzikante, Andris Ozols, Maris Ozolins. 

https://spie.org/Publications/Proceedings/Volume/7142

  1. J. Spigulis, L. Gailite, A. Lihachev, R. Erts. Simultaneous recording of skin blood pulsations at different vascular depths by multi-wavelength photoplethysmography, Appl. Opt., v. 46, No. 10, pp. 1754-1759 (2007).
  2. Lihachev, J. Spigulis. Skin autofluorescence fading at 405/532 nm laser excitation. IEEE Xplore, 10.1109/NO, pp. 63-65 (2007).
  3. Soto Thompson, T. Johansson, N. Bendsoe, A. Derjabo, J. Kapostinsh, S. Palsson, U. Stenram, S. Andesson-Engels, J. Spigulis, S. Svanberg, K. Svanberg. Photodynamic therapy of nodural Basal Cell Carcinoma with multi-fibre contact light delivery, J. Envir. Path., Toxic. Onc., v. 25, p. 411-424 (2006).
  4. Lihachev, J. Spigulis. Skin autofluorescence: intensity fading at 405 nm and 532 nm laser excitation. Latv. J. Phys. Techn. Sci., No. 2(II), pp. 116-120 (2006).
  5. J. Spigulis. Optical non-invasive monitoring of skin blood pulsations. Appl. Opt., v. 44, No. 10, pp. 1850-1857 (2005).
  6. R. Erts, J. Spigulis, I. Kukulis, M. Ozols. Bilateral photoplethysmography studies of the leg arterial stenosis. Physiol. Meas., v. 26, pp. 865-874 (2005).
  7. J. Spigulis. Side-emitting optical fibers brighten our world in new ways. Opt. Photon. News, pp. 34-39, Oct. (2005).
  8. "Advanced Optical Devices, Technologies, and Medical Applications", SPIE Proceedings vol. 5123 (2003), Editors: J. Spigulis, J. Teteris, M. Ozolinsh, A. Lusis,  https://www.spiedigitallibrary.org/conference-proceedings-of-spie/5123.toc
  9. Apine, J. Spigulis, P. A. Oberg,  Microcirculation in masseteric muscles at permanent muscular facial pain in krandiomandibular dysfunction, Med. Biol. Eng. Comput., v. 37, p. 327, 1999.
  10. Y. Dektyar, J. Spigulis, et al. Joint Baltic Biomedical Engineering and Physics courses. – Med. Biol. Eng. Comput., v. 37, Suppl. 1, p. 144-145, 1999.
  11. G. Venckus, J. Spigulis. Frequency filtering effects on the single period photoplethysmography signals. Med. Biol. Eng. Comput., v. 37, Suppl. 1, pp. 218-219 (1999).
  12. J. Spigulis, J. Lazdins, D. Pfafrods, M. Stafeckis. Side-emitting optical fibers for clinical applications. Med. Biol. Eng. Comput., v.34, Suppl.1, Pt. 1. p. 285-286 (1996).
  13. "Optical Inorganic Dielectric Materials and Devices", SPIE Proceedings vol. 2967 (1997), Editors: A. Krumins, D. K. Milllers, A. Sternberg, J. Spigulis. 

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/2967.toc

  1. J. Spigulis. Compact dielectric reflective elements. 1. Half-sphere concentrators of radially emitted light. Appl. Opt., v. 33, No. 25, p. 5970 – 5974 (1994).
  2. J. Spigulis, J. Lazdins. Compact dielectric reflective elements. 2. Multichannel filter of closely spaced spectral bands. Appl. Opt., v. 33, No. 28, p. 6638-6641 (1994).
  3. J. Spigulis, A. Rieba, M. Vitols. Detector of the optical fiber faults. PTE, Moscow (Instrum. & Experim. Techn., Plenum Publ., USA), No 6, p. 184 (1989).
  4. J. Spigulis. Radio-frequency electrodeless tubes as optical temperature sensors.  PTE, Moscow (Instrum. & Experim. Techn., Plenum Publ., USA), No.3, p. 209 (1983).
  5. A.Briuhovetski, J. Spigulis, R. Orlov. Calibrator of pulsed radiation. PTE, Moscow (Instrum. & Experim. Techniques, Plenum Publ., USA), No 1, p. 225 – 226 (1983).
  6. A.Bulishev, V.Malkin, N.Preobrazhensky, J.Spigulis. Kinetics of excitation transfer in mixtures of metal vapors and molecular gases. Opt. Spectrosc. (USSR), v.46, No. 6, p. 639 (1979).

 

Papers in Conference Proceedings (internationally cited)

 

  1. J.Spigulis, U.Rubins, E.Kviesis-Kipge, I.Saknite, I.Oshina, E.Vasilisina, A.K.Krievina, “Diagnostic spectral imaging of skin and nasal mucosa by RGB laser-based prototype devices”, Proc.SPIE 13009, 130090C (2024). https://doi.org/10.1117/12.3018710.

2.     I.Oshina,  J.Spigulis, "3D-representation of skin malformations using spectral line imaging and modified Beer-Lambert law", Proc. SPIE 12665, 126650T (2023). https://doi.org/10.1117/12.2687959.

3.     J.Spigulis, E.Kviesis-Kipge, U.Rubins, I.Oshina, M.Mileiko, “RGB laser-illuminated spectral imaging: applications in dermatology and endoscopy”, Proc.IFMBE, v.89, pp. 138-144 (2023). https://doi.org/10.1007/978-3-031-37132-5_18.

4.     I.Oshina, J.Spigulis, “Potential of the Beer–Lambert law for skin chromophore mapping from diffuse reflectance images”, Optics InfoBase Conference Papers: ECBO 2021,  ETu2A.27 (2021). https://www.osapublishing.org/viewmedia.cfm?uri=ECBO-2021-ETu2A.27.

5.     M.Bürmen, P.Naglič, J.Spigulis, “Comparison of in-vivo measured optical path length distribution of backscattered light in human skin and time-resolved Monte Carlo simulations”, Optics InfoBase Conference Papers: ECBO 2021, ETu2A.15 (2021). https://www.osapublishing.org/abstract.cfm?uri=ECBO-2021-ETu2A.15.

6.     M.Bürmen, P.Naglič, J.Spigulis, “Comparison of in-vivo measured optical path length distribution of backscattered light in human skin and time-resolved Monte Carlo simulations”, Optics InfoBase Conference Papers: ECBO 2021, ETu2A.15 (2021). https://www.osapublishing.org/abstract.cfm?uri=ECBO-2021-ETu2A.15.; Proc. SPIE 11920, 119201V (2021). doi:10.1117/12.2615424.

7.     J.Spigulis, V.Lukinsone, I.Oshina, E.Kviesis-Kipge, M.Tamosiunas, A.Lihachev, "Riga Group’s recent results on laser applications for skin diagnostics", J.Phys.: Conf. Ser. 1859, 012033 (2021). https://iopscience.iop.org/article/10.1088/1742-6596/1859/1/012033.

8.     J.Spigulis, V.Lukinsone, U.Rubins, A.Maslobojeva, M.Kuzminskis, “Skin-remitted photon path lengths: Experimental study”, in Biomedical Optics 2020, OSA Technical Digest, paper JW3A.1 (2020). https://www.osapublishing.org/abstract.cfm?URI=Microscopy-2020-JW3A.1

9.     J.Spigulis, I.Kuzmina, I.Lihacova, V.Lukinsone, B.Cugmas, A.Grabovskis, E.Kviesis-Kipge, A.Lihachev,  “Biophotonics research in Riga: recent projects and results”, Proc.SPIE 11585, 1158502 (2020).

10. B.Cugmas, D.Viškere, E.Štruc, J.Spigulis, "Selection of erythema index and image sampling method for the objective erythema estimation in dogs with atopic dermatitis", Proc. SPIE 11585, 115850E (2020); https://doi.org/10.1117/12.2581997.

11. E.Borisova, T.Genova, V.Mircheva, P.Troyanova, I.Bratchenko, L.Bratchenko,Y.Khristoforova, V.Zakharov, I.Lihacova, A.Lihachev, J.Spigulis, "Multispectral fluorescence detection of pigmented cutaneous tumours", Proc. SPIE 11585, 1158504  (2020); https://doi.org/10.1117/12.2581967.

12. J.Spigulis, I.Kuzmina, V.Lukinsone, M.Tamošiūnas, I.Oshina, L.Ozolina, A.Maslobojeva, M.Kuzminskis, D.Ivanov, E.Borisova, “Towards combined multispectral, FLIM and Raman imaging for skin diagnostics”, Proc.SPIE 11232, 112320N-1 (2020).

13. J.Spigulis, Z.Rupenheits, M.Matulenko, I.Oshina,U.Rubins, “A snapshot multi-wavelengths imaging device for in-vivo skin diagnostics”, Proc.SPIE 11232, 112320I-1 (2020).

14. Z.Marcinkevics, D.Briljonoks, H.Kronberga, J.Spigulis, “LED-bed therapy of cardiovascular disorders: a volunteer study”, Proc.SPIE 11221, 112210R (2020).

15. I.Kuzmina, V.Lukinsone, U.Rubins, I.Osina, L.Dambite, A.Maslobojeva, J.Spigulis, “Agar-based phantoms for skin diagnostic imaging”, Proc. SPIE 11363, 113630F (2020). doi: 10.1117/12.2555674.

16. 10.V. Lukinsone, I. Kuzmina, M. Tamosiunas, A. Maslobojeva,M. Kuzminskis, U. Rubins, J. Spigulis, “Remitted photon path length in human skin, skin phantoms and cell cultures”, Proc. SPIE 11363, 1136320 (2020). doi: 10.1117/12.2555822.

17. 11.E.Borisova, D.Ivanov, B.Kolev, T.Genova, V.Mircheva, S.Ilyov, L.Zaharieva,  I.Lihachova, A.Lihachovs, J.Spigulis, P.Troyanova, "Autofluorescence spectroscopy of cutaneous neoplasia under ultraviolet, visible and near infrared excitation", Proc. SPIE 11363, 113630Z (2020); https://doi.org/10.1117/12.2555982.

18. 12.J.Spigulis, I.Oshina, M.Matulenko, “Laser illumination designs for snapshot multi-spectral-line imaging” , IEEE Xplore, https://ieeexplore.ieee.org/document/8872998 (2019).

19. J.Spigulis, I.Oshina, P.Potapovs, K. Lauberts, “Snapshot multi-spectral-line imaging for applications in dermatology and forensics”, Proc.SPIE, 10881, 1088139 (2019).

20. V. Lukinsone, M. Osis, J. Latvels, I. Kuzmina, U. Rubins, N. Zorina, A.Maslobojeva, J. Spigulis, "Towards direct measurements of remitted photon path lengths in skin: kinetic studies in the range 520-800 nm", Proc. SPIE 11075, 1107505 (2019).

21. V.Lukinsone, R.Veilande, E.V.Plorina, I.Kuzmina, D.Bliznuks, K.Boločko, A.Derjabo, I.Lihacova, J.Spigulis, “Multispectral and autofluorescence RGB imaging for skin cancer diagnostics”, Proc.SPIE 11065, 110650A (2019).

22. M.Lange, N.Kiss, L.Fesus, E.V. Plorina, A.Derjabo, J.Spigulis, “Non-invasive LED-based screening solution for skin cancer“, Proc.SPIE 11073, 11073-17 (2019).

23. A.Sdobnov, A.Bykov, A.Popov, I.Lihacova, A.Lihachev, J.Spigulis, I.Meglinski, “Combined multi-wavelength laser speckle contrast imaging and diffuse reflectance imaging for skin perfusion assessment”, Proc. SPIE 11075, 110751F (2019).

24. B.Cugmas, J.Spigulis, “Clinical evaluation of automated capillary refill time estimation in dogs and cats”, Proc.SPIE 10868, 10868-1N (2019).

25. B.Cugmas, J.Spigulis, “Biophotonics in veterinary medicine: the first steps toward clinical translation”, Proc.SPIE 10885, 10885-20 (2019).

26. I.Oshina, P.Potapovs, J.Spigulis, “Spectral imaging system for money counterfeit detection”, OSA Technical Digest, ITu3B.3, https://doi.org/10.1364/ISA.2019.ITu3B.3 (2019).

27. J.Spigulis, A.Lihachev, V.Lukinsone, M.Osis, I.Oshina, “Lasers for in-vivo skin diagnostics: some recent developments”, Proc. SPIE 11047, 1104703 (2019).

28. E.Borisova, A.Gisbrecht, T.Genova-Hristova, P.Troyanova, E.Pavlova, N.Penkov, I.Bratchenko, V.Zakharov, I.Lihachova, I.Kuzmina, J.Spigulis, "Multispectral autoflourescence detection of skin neoplasia using steady-state techniques," Proc. SPIE 11047, 1104704 (2019. ).

29. M.Lange, E.V.Plorina, A.Derjabo, I.ihacova, I.Osina, D.Bliznuks, J.Spigulis, “Evaluating the aging of the scars after cancer removal by using multispectral diagnostic device”, Biomedical Optics Congress 2018, OSA Technical Digest, JTh3A.7, https://doi.org/10.1364/TRANSLATIONAL.2018.JTh3A.7 (2018).

30. B.Cugmas, J.Spigulis, “Challenges in automated estimation of capillary refill time in dogs”, Proc.SPIE 10501, 1050117 (2018).

31. I.Oshina, J.Spigulis, U.Rubins, E.Kviesis-Kipge, K.Lauberts, “Express RGB mapping of three to five skin chromophores”, Proc. SPIE-OSA ,10413, 104130M-1 (2017).

32. M.R.Garcia, M.D.Stringasci, D.V.Magalhăes, J.Spigulis, V.S. Bagnato, S. Pratavieira, “Photoaging Evaluation by RGB Images Using a Smartphone for Photodynamic Therapy Assessment”, Proc.SPIE-OSA, 10411, 1041108-1 (2017).

33. I.Kuzmina, U.Rubins, I.Saknite, J.Spigulis. „Rosacea assessment by erythema index and principal component analysis segmentation maps”,  Proc.SPIE 10592, 10592 04 (2017).

34. A.Lihachev, l.Lihacova, J.Spigulis, T.Trebst, M.Wehner, “Monitoring soft tissue coagulation by optical spectroscopy”, Proc.SPIE 10592, 10592 0D (2017).

35. A.Zhelyazkova, I.Kuzmina, E.Borisova, N.Penkov, Ts.Genova, J.Spigulis, L.Avramov. Investigating different skin and gastrointestinal tract (GIT) pathologies ex vivo by autofluorescence spectroscopy and optical imaging, Proc. SPIE 10226, 1022615 (2017).

36. I.Saknite, A.Grabovskis, S.Kazune, U.Rubins, Z.Marcinkevics, K.Volceka, E.Kviesis-Kipge, J.Spigulis. Novel hybrid technology for early diagnosis of sepsis. Proc.SPIE 10057, 100570F (2017).

37. J. Spigulis, I. Oshina, Z. Rupenheits, "Smartphone single-snapshot mapping of skin chromophores," in Biomedical Optics 2016, OSA Technical Digest (online), JTu3A.46 (2016), https://www.osapublishing.org/abstract.cfm?uri=Cancer-2016-JTu3A.46.

38. U.Rubins, J.Spigulis, A.Miscuks. Photoplethysmography imaging algorithm for continuous monitoring of regional anesthesia. ESTIMedia'16 Proceedings of the 14th ACM/IEEE Symposium on Embedded Systems for Real-Time Multimedia, pp. 67-71 (2016).

39. D.Jakovels, I.Saknite, D.Bliznuks, J.Spigulis, R.Kadikis. Benign-atypical nevi discrimination using diffuse reflectance and fluorescence multispectral imaging system. BioPhotonics 2015 (Florence, IT), 7304026 (2015) – online.

40. D.Bliznuks, D.Jakovels, I.Saknite, J.Spigulis. Mobile platform for online processing of multimodal skin optical images: Using online Matlab server for processing remission, fluorescence and laser speckle images, obtained by using novel handheld device.  BioPhotonics 2015 (Florence, IT), 7304024 (2015) - online.

41. I.Saknite, J.Spigulis. Determination of in vivo skin moisture level by near-infrared reflectance spectroscopy. Proc.SPIE, 9332, 93320Y (2015).

42. J.Spigulis, I.Oshina. 3x3 technique for RGB snapshot mapping of skin chromophores. OSA Techn.Digests, Bio-Optics: Design and Application, online (2015).

43. J.Spigulis, L.Elste. Single-snapshot RGB multispectral imaging at fixed wavelengths: proof of concept. Proc.SPIE, 8937, 89370L (2014).

44. A.Lihachev, I.Ferulova,.J.Spigulis, D.Chorvat. Parallel measurements of in-vivo skin autofluorescence lifetimes and photobleaching rates. IFMBE Proc. 48, 78-81 (2014).

45. D.Jakovels, I.Saknite, G.Krievina, J.Zaharans, J.Spigulis. Mobile phone based laser speckle contrast imager for assessment of skin blood flow. Proc.SPIE 9421, 94210J (2014).

46. N.Lesina, J.Spigulis. Hands-on optics and photonics outreach in Riga. Proc. SPIE 9289, 92892I (2014).

47. D.Jakovels, I.Saknite, J.Spigulis. Implementation of laser speckle contrast analysis as connection kit for mobile phone for assessment of skin blood flow. Proc.SPIE, 9129, 91293I (2014).

48. L.Asare, E.Kviesis-Kipge, J.Spigulis. Clinical measurement analysus of multi-spectral photoplethysmography biosensors. Proc.SPIE, 9129, 912933 (2014).

49. I.Saknite, D.Jakovels, J.Spigulis. Diffuse reflectance and fluorescence multispectral imaging system for assessment of skin. Proc.SPIE, 9129, 91293H (2014).

50. U.Rubins, J.Spigulis, A.Miscuks. Application of color magnification technique for revealing skin microcircuration changes under regional anaesthetic input. Proc.SPIE, 9032, 903203 (2013).

51. A.Lihachev, D. Jakovels, I. Ferulova, J. Spigulis, M. Tamosiunas, S. Satkauskas, C. W. Lo, W. S. Chen. Fluorescence spectroscopy for estimation of anticancer drug sonodestruction in vitro . Proc. SPIE  9032, 90320D (2013).

52. D. Jakovels, A. Lihachev, J. Spigulis, S. Satkauskas, M. Tamosiunas, C. W. Lo, W. S. Chen.  Assessment of efficiencies of electroporation and sonoporation methods by using fluorescence RGB imaging method. Proc. SPIE  9032, 90320E (2013).

53. I.Saknite, E.Kviesis, J.Spigulis. Water detection in skin by dual-band photodiodes. .Proc. SPIE  9032, 90320O (2013).

54. I.Ferulova, A.Lihachev, J.Spigulis. Fluorescence lifetime spectroscopy: potential for in-vivo estimation of skin fluorophores changes after low power laser treatment. .Proc. SPIE  9032, 90320B (2013).

55. D.Jakovels, I.Lihacova, I.Kuzmina, J.Spigulis. Application of principal component analysis to multispectral imaging data for evaluation of pigmented skin lesions. Proc. SPIE  9032, 903204 (2013).

56. A.Bekina, V. Garancis, U. Rubins, J. Spigulis, L. Valeine, A. Berzina. Multimodal device for assessment of skin malformations . Proc. SPIE  9032, 903207 (2013).

57. A.Bekina, U.Rubins, I.Lihachova, J.Zaharans, J.Spigulis. Skin chromophore mapping by means of a modifified video-microscope for skin malformation diagnosis. Proc.SPIE, 8856, 88562G (2013).

58. L.Asare, J.Spigulis. Analysis of multispectral photoplethysmography biosensors. Proc.SPIE, 8801, 880106 (2013).

59. J.Spigulis, V.Garancis, U.Rubins, E.Zaharans, J.Zaharans, L.Elste, “A device for multimodal imaging of skin”, Proc. SPIE, v. 8574,  85740J  (2013).

60. D.Jakovels, U.Rubins, J.Spigulis. LASCA and PPG imaging for non-contact assessment of skin blood supply. Proc. SPIE, v.8668, 866849 (2013).

61. I.Lihacova, A.Derjabo, J.Spigulis. A multispectral imaging approach for diagnostics of skin pathologies. Proc. SPIE 8798, 87980X (2013).

62. D. Jakovels, I. Lihacova, I. Kuzmina, J. Spigulis. Evaluation of skin melanoma in spectral range 450-950 nm using principal component analysis. Proc. SPIE 8803, 88030C (2013).

63. U. Rubins, J. Spigulis, L. Valeine, A. Berzina. Semi-automatic detection of skin malformations by analysis of spectral images .Proc. SPIE  8798, 87980S (2013).

64. A.Bekina, U.Rubins, J.Zaharans, J.Spigulis. Skin chromophore mapping by modified video microscope. Proc. SPIE  8798, 87980T (2013).

65. I.Saknite, M.Lange, D.Jakovels, J.Spigulis. Determination of chromophore distribution in skin by spectral imaging Proc. SPIE,v.8474 , 84740K (2012).

66. D.Jakovels, I.Kuzmina, A.Berzina, J.Spigulis. RGB imaging system for monitoring of skin vascular malformation's laser therapy. Proc. SPIE 8427 (Photonics Europe, Brussels), 842737 (2012).

67. J.Spigulis, D.Jakovels, L.Elste. Towards single snapshot multispectral skin assessment. Proc. SPIE 8216, 82160L (2012).

68. I.Ferulova, J.Lesins, A.Lihachev, D.Jakovels, J.Spigulis, "Influence of low power CW laser irradiation on skin hemoglobin changes", Proc. SPIE 8427 (Photonics Europe, Brussels), 84273I (2012).

69. I.Diebele, A.Bekina, A.Derjabo, J.Kapostinsh, I.Kuzmina, J.Spigulis. Analysis of skin basalioma and melanoma by multispectral imaging. Proc. SPIE 8427 (Photonics Europe, Brussels), 842732 (2012).

70. L.Asare, M.Ozols, U.Rubins, O.Rubenis, J.Spigulis. Clinical measurements with multi-spectral photoplethysmography sensors. Proc. SPIE 8427 (Photonics Europe, Brussels), 842734 (2012).

71. U. Rubins, V. Upmalis, O. Rubenis, D. Jakovels, J. Spigulis. Real-time photoplethysmography imaging system. Proc. IFMBE, v. 34 (NBC-15, Aalborg, DK), 183-186 (2011).

72. I.Kuzmina, I. Diebele, L. Valeine, D. Jakovels, A. Kempele, J. Kapostinsh, J. Spigulis. Multi-spectral imaging analysis of pigmented and vascular skin lesions: results of a clinical trial.Proc. SPIE, v.7883 (BIOS’11, San Francisco, USA), 788312 (2011).

73. L. Asare, E.Kviesis–Kipge, A.Grabovskis, U.Rubins, R.Erts, J.Spigulis. Multi-spectral photoplethysmography biosensor. Proc. SPIE, v. 8073 (OOE, Praha, CZ), 80731Z (2011).

74. D. Jakovels, J. Spigulis, L. Rogule. RGB mapping of hemoglobin distribution in skin. Proc. SPIE, v. 8087 (ECBO, Munich, DE), 80872B (2011).

75. A.Lihachev , K. Rozniece, J. Lesins, J. Spigulis. Photobleaching measurements of pigmented and vascular skin lesions: results of a clinical trial. Proc. SPIE, v.8087 (ECBO, Munich, DE), 80872F (2011).

76. I.Diebele, I. Kuzmina, J. Kapostinsh, A. Derjabo, J. Spigulis Melanoma-nevus differentiation by multispectral imaging. Proc. SPIE, v. 8087 (ECBO, Munich, DE), 80872G (2011).

77. J. Lesinsh, A.Lihachev, R. Rudys, S. Bagdonas, J. Spigulis. Skin autofluorescence photobleaching and photo-memory. Proc. SPIE, v.8092 (ECBO, Munich, DE), 80920N (2011).

78. L. Asare, E. Kviesis-Kipge, U. Rubins, O. Rubenis, J. Spigulis. Multi-spectral photoplethysmography technique for parallel monitoring of pulse shapes at different tissue depths. Proc. SPIE, v. 8087 (ECBO, Munich, DE), 80872E (2011).

79. D. Jakovels, J. Spigulis. RGB imaging of laser-excited skin autofluorescence bleaching rates. Proc. SPIE, vol. 7376 (LALS, Oulu, FI), 737618 (2010).

80. I.Kuzmina, L. Asare, I. Diebele, D. Jakovels, A. Kempele, J. Spigulis. Multispectral imaging of pigmented and vascular cutaneous malformations: the influence of laser treatment.Proc. SPIE, vol. 7376 (LALS, Oulu, FI), 73760J (2010).

81. J. Spigulis, D. Jakovels, U. Rubins. Multi-spectral skin imaging by a consumer photo-camera. Proc. SPIE Vol. 7557 (BIOS 2010, San Francisco, USA), 75570M (2010).

82. D. Jakovels, J. Spigulis, I. Saknite. Multi-spectral mapping of in-vivo skin haemoglobin and melanin.  Proc. SPIE, Vol.7715 (Photonics Europe, Brussels, BE), 77152Z1-6 (2010).

83. E. Kviesis-Kipge, E. Čurkste, J. Spigulis, L. Eihvalde. Real-time analysis of skin capillary-refill processes using blue LED. Proc. SPIE, Vol.7715 (Photonics Europe, Brussels, BE), 7715231-5 (2010).

84. R. Erts, U. Rubins, and J. Spigulis, Monitoring of blood pulsation using non-contact technique, Proc. IFMBE 25/VII (11th World Congr. Med Phys. Biomed. Engin., Munich), Springer, pp. 754-756 (2009).

85. E. Kviesis-Kipge, E. Curkste, J. Spigulis and D. Gardovska. Optical studies of the capillary refill kinetics in fingertips, Proc. IFMBE, 25/VII (11th World Congr. Med Phys. Biomed. Engin., Munich), pp. 377-379 (2009).

86. J. Spigulis, R. Erts, V. Nikiforovs, E. Kviesis-Kipge. Wearable wireless photoplethysmography sensors. Proc. SPIE, vol. 6991 (Photonics Europe, Strasbourg, FR), 6991120, 2008.

87. J. Paturskis, V. Veliks, M. Ozols, I. Svikis, R. Erts, J. Spigulis. Photoplethysmography device for detection of changes in the vasomotor parameters of small laboratory animals. Proc. IFMBE, v. 20 (NBC-14, Riga, LV), pp. 386-389, 2008.

88. J. Spigulis, A. Lihachev, L. Gailite, R. Erts. Novel laser technologies for human skin in-vivo assessment. Proc. SPIE, Vol. 7022 (ALT’07 - Advanced Laser Technologies, Levi, FI),70220N, 2008.

89. J. Spigulis, L. Gailite, A. Lihachev. Contact probe pressure effects in skin multi-wavelength photoplethysmography. Proc. SPIE-OSA, v. 6628 (Diagnostic Optical Spectroscopy in Biomedicine IV, Munich, DE), 2007, pp. 66281F-1 – 66281F-8.

90. J. Spigulis. Biophotonics Master studies: teaching and training experience at University of Latvia. Proc. ETOP 2007 (ICO-OSA-SPIE Education and Training in Optics and Photonics, Ottawa, CA - CD-format), 2007. http://spie.org/etop/etop2007.html

91. J. Spigulis, L. Gailite, A. Lihachev. Multi-wavelength photoplethysmography for simultaneous recording of skin blood pulsations at different vascular depths. Proc. SPIE, vol. 6430 (BIOS’07, San Jose, USA), 2007, pp. 64301I-1 - 64301I-6.

92. I.Kuzmina, A. Lihachev, L. Gailite, J. Spigulis. Compact multi-functional skin spectrometry set-up. Proc. SPIE, vol. 6596 (Advanced Optical Materials, Technologies and Devices, Vilnius, LT), 2007, pp. 6596OT1-6596OT6.

93. J. Spigulis. Application prospects of silica core side-glowing optical fibers. Proc. SPIE v. 5952 (Optical Fibers II: Applications, Warsaw, PL), 2005, pp. 595203-1 – 595203-6.

94. R. Erts, J. Spigulis, M. Ozols. Optical systems for non-invasive cardiovascular biosensing. Proc. SPIE v. 5908 (Optical Information Systems, San Diego, CA), 2005, pp. 59080J-1 – J7.

95. R. Erts, I. Kukulis, J. Spigulis, L. Kere. Dual channel photoplethysmography studies of cardio-vascular response to the body position changes, Proc. SPIE v. 5859 (European Biomedical Optics Symposium EBIOS’05, Munich, DE), 2005, pp. 58591K-1 – K5.

96. J. Spigulis. Optical non-invasive monitoring of skin blood pulsations. Proc. SPIE (Avdanced Optical Materials and Devices – 4, Tartu, EE), 2005, pp. 1R1-1R11.

97. R. Erts, I. Kukulis, J. Spigulis. Photonic vascular diagnostics by four-channel photoplethysmography. Proc. SPIE (Avdanced Optical Materials and Devices – 4, Tartu, EE), 2005, pp. 1L1-1L9.

98. J. Spigulis, R. Erts, I. Kukulis, M. Ozols, K. Prieditis. Optical multi-channel sensing of skin blood pulsations. Proc. SPIE, Vol. 5459 (Optical Sensing, Photonics Europe, Strasbourg, FR), 2004, pp. 46-53.

99. J. Spigulis, R. Erts, M. Ozols. Optical multi-channel monitoring of skin blood pulsations for cardiovascular assessment. Proc. SPIE, Vol. 5318 (Advanced Biomedical and Clinical Diagnostic Systems, BIOS’04, San Jose, USA), 2004, pp. 133-139.

100.                 J. Spigulis, R. Erts, M. Ozols. A portable two-channel PPG cardiovascular sensor device. Proc. SPIE, Vol. 5138 (Photon Migration and Diffuse-Light Imaging, Munich, DE), 2003 pp. 65-71.

101.                 J. Spigulis, R. Erts, U. Rubins. Micro-circulation of skin blood: optical monitoring by advanced photoplethysmography techniques. – Proc. SPIE Vol. 5119 (Bioengineered and Bioinspired Systems, Maspalomas, ES), 2003, pp. 219-225.

102.                 M. Stagitis, J. Spigulis. Optical pressure sensor based on the side-emitting optical fibre. - Proc. SPIE Vol. 5123 (Advanced Optical Devices and Medical Applications, Riga, LV), 2003, pp. 33-38.

103.                 J. Spigulis, M. Ozols, R. Erts, K. Prieditis. A portable device for optical assessment of the cardiovascular condition. Proc. SPIE Vol. 5123 (Advanced Optical Devices and Medical Applications, Riga, LV), 2003, pp. 313-319.

104.                 J. Spigulis, I. Kukulis, E. Fridenberga, G. Venckus. Potential of advanced photoplethysmography sensing for non-invasive vascular diagnostics and early screening. Proc. SPIE, Vol. 4625 (Biomedical Optics Symposium BIOS ’02, San Jose, USA), 2002, p. 48-53.

105.                 J. Spigulis. Teaching of laser-medical topics: Latvian experience. Proc. SPIE., Vol. 4903 (Laser Florence 2001: A Window on the Laser Medicine World, Florence, IT), 2002, p. 197-201.

106.                 J. Spigulis, A. Pfafrods. Pressure sensitivity of the side-glowing optical fibres. Proc. SPIE Vol. 4318 (Smart Optical Inorganic Structures and Devices, ADOM-2, Vilnius, LT), 2001, p. 58-65.

107.                 J. Spigulis, G. Venckus, M. Ozols. Optical sensing for early cardio-vascular diagnostics. Proc. SPIE. Vol. 3911 (Biomedical Optics Symposium BIOS ‘2000, San Jose, USA), 2000, p. 27-31.

108.                 J. Spigulis. Master’s level education in Biomedical Optics: four-year experience at University of Latvia. Proc. SPIE Vol. 3831 (Education and Training in Optics and Photonics, Cancun, MX), 1999, p. 189-192.

109.                 J. Spigulis, U. Rubins. Photoplethysmographic sensor with smoothed output signals. Proc. SPIE  Vol, 3570 (Biomedical Optics Europe, Stockholm, SE), 1998, p. 195-199.

110.                 J. Spigulis. MSc course programme on Biomedical Optics. Proc. SPIE Vol. 3190, 1997 (Education and Training in Optics, Delft, NL), p. 342-345.

111.                 J. Spigulis, D. Pfafrods. Clinical potential of the side-glowing optical fibers. Proc. SPIE Vol. 2977 (Biomedical Optics Symposium BIOS ’97, San Jose, USA), 1997, p. 84-87.

112.                 J. Spigulis, D. Pfafrods, M. Stafeckis, W. Jelinska-Platace. The "glowing" optical fibre designs and parameters. Proc. SPIE Vol. 2967 (Advanced Optical Materials and Devices, Riga), 1997, p. 226-231. 

113.                 J. Spigulis, D. Pfafrods, M. Stafeckis. Optical fiber diffusive tip designs for medical laser-lightguide delivery systems. Proc. SPIE Vol. 2328, 1994 ("Biomedical Optics Europe '94", Lille, France), p. 69-75.

114.                 J. Spigulis, J. Lazdins, G. Barens. Fiberoptical intensity-ratio refractometer with digital display. Proc. SPIE Vol. 2068 (Optical Tools for Manufacturing and Advanced  Automation, Boston, USA), 1994, p. 308-312.

115.                       J. Spigulis. Compact illuminators, collimators and focusers with half-spherical input aperture. Proc. SPIE Vol. 2065 (Optical Tools for Manufacturing and Advanced  Automation, Boston, USA), 1994, p. 54–59.