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Khanna N, Klyushnenkova E, Gaynor A, Dark M, Melamed J, Bennett M, Deepak J. Integrating a Systematic, Comprehensive E-Cigarette and Vaping Assessment Tool into the Electronic Health Record. J Am Board Fam Med 2023; 36:405-413. [PMID: 37290827 DOI: 10.3122/jabfm.2022.220410r1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/08/2023] [Accepted: 02/13/2023] [Indexed: 06/10/2023] Open
Abstract
BACKGROUND Recently, the use of electronic cigarettes increased sharply, leading to increased e-cigarette, or Vaping Product Use-Associated Lung Injury (EVALI), and other acute pulmonary conditions. There is an urgent need for clinical information about e-cigarette users to identify factors that contribute to EVALI. We developed an e-cigarette/vaping assessment tool (EVAT) that was integrated into the Electronic Health Record (EHR) of a large state-wide medical system and initiated a system-wide dissemination and education to support its use. METHODS EVAT documented current vaping status, history, and e-cigarette content (nicotine, cannabinoids, and/or flavoring). Educational materials and presentations were developed via a comprehensive literature review. EVAT utilization in the EHR was assessed quarterly. Patients' demographic data and clinical site name were also collected. RESULTS The EVAT was built, validated, and integrated with the EHR in July 2020. Live and virtual seminars were conducted for prescribing providers and clinical staff. Asynchronous training was offered using podcasts, e-mails, and Epic tip sheets. Participants were informed about vaping harm and EVALI and instructed on the use of EVAT. As of December 31, 2022, EVAT was used 988,181 times, with 376,559 unique patients evaluated. Overall, 1,063 hospital units and affiliated ambulatory clinics used EVAT, including 64 Primary Care, 95 Pediatrics, and 874 Specialty sites. CONCLUSIONS EVAT was successfully implemented. Continued outreach efforts are needed to further increase its usage. Education materials should be enhanced to help providers to reach youth and vulnerable populations and connect patients to the tobacco treatment resources.
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Affiliation(s)
- Niharika Khanna
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
| | - Elena Klyushnenkova
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
| | - Adam Gaynor
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
| | - Michael Dark
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
| | - Julia Melamed
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
| | - Melanie Bennett
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
| | - Janaki Deepak
- From the Department of Family and Community Medicine, University of Maryland, Baltimore, (NK, EK, AG, MD); Department of Internal Medicine, Department of Pulmonology and Critical Care, University of Maryland, Baltimore (JM, JD); Department of Psychiatry, University of Maryland, Baltimore (MB)
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Dark M, Klyushnenkova E, Gaynor A, Kernan C, Khanna N. Tobacco Cessation Champions: Recognizing Physicians Who Ask, Advise, and Refer. Ann Fam Med 2022; 20:579. [PMID: 36443068 PMCID: PMC9705038 DOI: 10.1370/afm.2891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/02/2022] [Accepted: 08/09/2022] [Indexed: 12/14/2022] Open
Affiliation(s)
- Michael Dark
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Elena Klyushnenkova
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Adam Gaynor
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Colleen Kernan
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Niharika Khanna
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
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Hobbs KJ, Porter E, Wait C, Dark M, MacKay RJ. Magnetic resonance imaging of the normal equine pituitary gland. Vet Radiol Ultrasound 2022; 63:450-455. [PMID: 35188303 DOI: 10.1111/vru.13072] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/20/2021] [Accepted: 12/22/2021] [Indexed: 11/28/2022] Open
Abstract
Magnetic resonance imaging is increasingly available for evaluation of horses with suspected pituitary adenomas; however, published studies describing the MRI features of normal equine pituitary glands are currently lacking. This retrospective, descriptive, anatomic study describes the MRI appearance and size of presumed normal equine pituitary glands and assesses potential correlations between pituitary size, brain size, and patient weight. These findings serve as a reference for MRI evaluation of the equine pituitary gland. Inclusion criteria consisted of adult horses (2-15 years old), over 300 kg with no evidence of Pituitary pars intermedia dysfunction (PPID) and no pituitary abnormalities identified with MRI, yielding 27 horses. Histology was available on seven pituitary glands; all were considered normal by a board-certified anatomic pathologist. Imaging features of the glands were evaluated on T2-weighted and pre- and postcontrast T1-weighted images. Pituitary length, width, and height and brain height and width were measured by two authors on transverse and mid-sagittal plane postcontrast T1 weighted images. The mean ± SD pituitary gland width was 21.0 ± 2.4 mm, height: 10.4 ± 1.9 mm, and length: 24.5 ± 2.7 mm. There were no significant correlations using a Pearson's correlation coefficient between pituitary and brain measurements, pituitary measurement, and body weight, or between brain measurements and body weight. A statistical difference was not identified using an unpaired t-test (p > 0.05) in pituitary and brain measurements between necropsied and non-necropsied horses. Relative to the cerebral white matter, all pituitary glands were isointense to slightly hyperintense on T1-weighted images and isointense on T2-weighted images, with the exception of a focal T1-weighted hyperintensity that was present in the caudal aspect of the pituitary gland in 88% of horses. All pituitary glands were homogenously contrast enhancing. Pituitary dimensions did not correlate with either brain size or body weight in horses.
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Affiliation(s)
- Kallie J Hobbs
- Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida, USA
| | - Erin Porter
- Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida, USA
| | - Courtney Wait
- Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida, USA
| | - Michael Dark
- Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida, USA
| | - Robert J MacKay
- Large Animal Clinical Sciences, University of Florida College of Veterinary Medicine, Gainesville, Florida, USA
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Cascio MJ, Whitley EM, Sahay B, Cortes-Hinojosa G, Chang LJ, Cowart J, Salute M, Sayour E, Dark M, Sandoval Z, Mitchell DA, Milner RJ. Canine osteosarcoma checkpoint expression correlates with metastasis and T-cell infiltrate. Vet Immunol Immunopathol 2020; 232:110169. [PMID: 33387703 DOI: 10.1016/j.vetimm.2020.110169] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 08/28/2020] [Accepted: 12/09/2020] [Indexed: 01/21/2023]
Abstract
BACKGROUND Immune-targeted therapies are being successfully implemented into cancer clinical practice. In particular checkpoint inhibitors are employed to modulate the immune microenvironment of solid tumors. We sought to determine the expression of PD-L1, HVEM, and B7H3 in human and canine osteosarcoma, and correlate expression with clinical features and tumor infiltrating lymphocytes in naturally-occurring canine osteosarcoma. METHODS Flow cytometry was used to measure ligand surface expression of five human and three canine cell lines. Immunohistochemistry was utilized for expression of ligands and lymphocyte markers in thirty-seven treatment-naïve canine osteosarcoma patients. RESULTS All cell lines expressed all three ligands at variable levels in both species. Metastatic lesions were associated with higher expression of all three ligands in patient tumor samples. PD-L1 expression strongly correlated with B7H3 and HVEM expression, while HVEM and B7H3 were weakly correlated. Whereas peritumoral T-cell expression positively correlated with PD-L1 and HVEM tumor expression, the presence of T-cells intratumorally were rare. Furthermore, intratumor penetration by T-cells was greatest in metastatic lesions, despite log-fold increases in peritumoral T-cells. In summary, PD-L1, HVEM, and B7H3 are expressed in osteosarcoma, with metastatic disease lesions expressing higher levels. We show for the first time that these ligands expressed on osteosarcoma cells positively correlate with each other and the presence of peritumoral T cell infiltration. Furthermore, osteosarcoma appears to be an intratumoral immune desert with significant resistance to effector T cells. Multiple agents targeting checkpoints are in clinical practice, and may have immune modulating benefit in osteosarcoma.
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Affiliation(s)
- Matthew J Cascio
- Department of Pediatrics, College of Medicine, University of Florida, Pediatric Hematology/Oncology, University of Florida, 1600 SW Archer Rd, RMHD204, PO Box 100298, Gainesville, FL, 32610, United States.
| | - Elizabeth M Whitley
- Pathologist Pathogenesis, LLC PO Box 140164, Gainesville, FL, 32614, United States
| | - Bikash Sahay
- Department of Infectious Diseases and Pathology, College of Veterinary, Medicine, University of Florida, PO Box 100880, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, United States
| | - Galaxia Cortes-Hinojosa
- School of Veterinary Medicine, Pontifical Catholic University of Chile, Av. Vicuña Mackenna 4860, Macul-Santiago, 7820436, Chile
| | - Lung-Ji Chang
- Professor of Molecular Genetics and Microbiology, University of Florida, P.O. Box 100266, Gainesville, FL, 32610-0266, United States
| | - Jonathan Cowart
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100126, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, United States
| | - Marc Salute
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100126, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, United States
| | - Elias Sayour
- Department of Pediatrics, College of Medicine, University of Florida, Pediatric Hematology/Oncology, University of Florida, 1600 SW Archer Rd, RMHD204, PO Box 100298, Gainesville, FL, 32610, United States; Department of Neurosurgery, University of Florida, P.O. Box 100265, Gainesville, FL, 32610-0265, United States
| | - Michael Dark
- Department of Comparative, Diagnostic & Population Medicine, University of Florida, PO Box 100123, 2015 SW 16th Ave, Gainesville, FL, 32610-0123, United States
| | - Zachary Sandoval
- College of Public Health and Health Professions, University of Florida, 2015 SW 16th Ave, Gainesville, FL, 32608, United States
| | - Duane A Mitchell
- Department of Neurosurgery, University of Florida, P.O. Box 100265, Gainesville, FL, 32610-0265, United States
| | - Rowan J Milner
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, PO Box 100126, 2015 SW 16th Ave, Gainesville, FL, 32610-0126, United States
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Khanna N, Gritzer L, Klyushnenkova E, Montgomery R, Dark M, Shah S, Shaya F. Practice Transformation Analytics Dashboard for Clinician Engagement. Ann Fam Med 2019; 17:S73-S76. [PMID: 31405880 PMCID: PMC6827660 DOI: 10.1370/afm.2382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/21/2018] [Accepted: 01/31/2019] [Indexed: 01/08/2023] Open
Abstract
PURPOSE Practice transformation in primary care is a movement toward data-driven redesign of care, patient-centered care delivery, and practitioner activation. A critical requirement for achieving practice transformation is availability of tools to engage practices. METHODS A total of 48 practices with 109 practice sites participate in the Garden Practice Transformation Network in Maryland (GPTN-Maryland) to work together toward practice transformation and readiness for the Quality Payment Program implemented by the Centers for Medicare & Medicaid Services. Practice-specific data are collected in GPTN-Maryland by practices themselves and by practice transformation coaches, and are provided by the Centers for Medicare & Medicaid Services. These data are overwhelming to practices when presented piecemeal or together, a barrier to practices taking action to ensure progress on the transformation spectrum. The GPTN-Maryland team therefore created a practice transformation analytics dashboard as a tool to present data that are actionable in care redesign. RESULTS When practices reviewed their data provided by the Centers for Medicare & Medicaid Services using the dashboard, they were often seeing, for the first time, cost data on their patients, trends in their key performance indicator data, and their practice transformation phase. Overall, 72% of practices found the dashboard engaging, and 48% found the data as presented to be actionable. CONCLUSIONS The practice transformation analytics dashboard encourages practices to advance in practice transformation and improvement of patient care delivery. This tool engaged practices in discussions about data, care redesign, and costs of care, and about how to develop sustainable change within their practices. Research is needed to study the impact of the dashboard on costs and quality of care delivery.
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Affiliation(s)
- Niharika Khanna
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Lauren Gritzer
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Elena Klyushnenkova
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | | | - Michael Dark
- Department of Family and Community Medicine, University of Maryland School of Medicine, Baltimore, Maryland
| | - Savyasachi Shah
- University of Maryland School of Pharmacy, Baltimore, Maryland
| | - Fadia Shaya
- University of Maryland School of Pharmacy, Baltimore, Maryland
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Gritzer L, Davenport M, Dark M, Khanna N. Coaching Small Primary Care Practices to Use Patient Portals. Ann Fam Med 2019; 17:S83. [PMID: 31405883 PMCID: PMC6827674 DOI: 10.1370/afm.2381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/31/2018] [Accepted: 12/13/2018] [Indexed: 11/09/2022] Open
Affiliation(s)
- Lauren Gritzer
- University of Maryland School of Medicine, Baltimore, Maryland
| | | | - Michael Dark
- University of Maryland School of Medicine, Baltimore, Maryland
| | - Niharika Khanna
- University of Maryland School of Medicine, Baltimore, Maryland
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Zoll WM, Prakoso D, Dark M, Liu J, Stockdale-Walden H, Long MT. Histologic characterization of eosinophilic encephalitis in horses in Florida. J Vet Diagn Invest 2018. [PMID: 29528809 DOI: 10.1177/1040638718763877] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Eosinophils within the central nervous system are abnormal and are usually associated with fungal or parasitic infections in horses. Causative agents include Halicephalobus gingivalis, Sarcocystis neurona, and Neospora hughesi. Confirmation of these organisms via specific testing is typically not performed, and final diagnoses are often presumptive. With molecular technology, many of these organisms can now be confirmed. This is important for emerging and zoonotic pathogens, including Angiostrongylus cantonensis, an emerging parasite of interest in the southeastern United States. We retrospectively analyzed eosinophilic encephalitides in Floridian horses for H. gingivalis, S. neurona, and A. cantonensis, applied descriptors to equine eosinophilic encephalitides, and determined if a relationship existed between these descriptions and specific etiologic agents. In a database search for horses with eosinophilic and other encephalitides submitted to the University of Florida, College of Veterinary Medicine, Anatomic Pathology Service, we identified 27 horses with encephalitis, and performed DNA isolation and rtPCR on formalin-fixed, paraffin-embedded blocks from these cases. Real-time PCR identified 6 horses positive for S. neurona and 4 horses positive for H. gingivalis; all horses were negative for A. cantonensis. All 25 control horses were negative for H. gingivalis, S. neurona, and A. cantonensis. Pattern analysis and eosinophil enumeration were not useful in differentiating among causes of eosinophilic encephalitides in horses in our study.
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Affiliation(s)
- Whitney M Zoll
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine (Zoll, Prakoso, Dark, Liu, Stockdale-Walden, Long), University of Florida, Gainesville, FL.,Emerging Pathogens Institute (Dark), University of Florida, Gainesville, FL
| | - Dhani Prakoso
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine (Zoll, Prakoso, Dark, Liu, Stockdale-Walden, Long), University of Florida, Gainesville, FL.,Emerging Pathogens Institute (Dark), University of Florida, Gainesville, FL
| | - Michael Dark
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine (Zoll, Prakoso, Dark, Liu, Stockdale-Walden, Long), University of Florida, Gainesville, FL.,Emerging Pathogens Institute (Dark), University of Florida, Gainesville, FL
| | - Junjie Liu
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine (Zoll, Prakoso, Dark, Liu, Stockdale-Walden, Long), University of Florida, Gainesville, FL.,Emerging Pathogens Institute (Dark), University of Florida, Gainesville, FL
| | - Heather Stockdale-Walden
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine (Zoll, Prakoso, Dark, Liu, Stockdale-Walden, Long), University of Florida, Gainesville, FL.,Emerging Pathogens Institute (Dark), University of Florida, Gainesville, FL
| | - Maureen T Long
- Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine (Zoll, Prakoso, Dark, Liu, Stockdale-Walden, Long), University of Florida, Gainesville, FL.,Emerging Pathogens Institute (Dark), University of Florida, Gainesville, FL
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Schaffer JL, Dark M, Itzkan I, Albagli D, Perelman L, von Rosenberg C, Feld MS. Mechanisms of meniscal tissue ablation by short pulse laser irradiation. Clin Orthop Relat Res 1995:30-6. [PMID: 7641455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A new experimental technique was developed to study short-pulsed laser ablation of biologic tissues (human meniscus and bovine tibial bone), water, and acrylic. The experimental technique was based on interferometric monitoring of the motion of the tissue surface to measure its laser-induced expansion after irradiation. The thermoelastic expansion of these materials after laser irradiation under subablation threshold was examined to determine its role in the initiation of ablation. The experimentally observed surface expansion of cortical bone and acrylic was in agreement with theoretical predictions. The movement of meniscal tissue was similar to that shown by water. The latter 2 materials showed additional features consistent with the growth and collapse of cavitation bubbles. The exact role of cavitation in the irradiation of meniscal tissue by laser light remains unknown, but may represent a clinically important mode of tissue ablation and postirradiation trauma.
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Affiliation(s)
- J L Schaffer
- Laboratory for the Study of Skeletal Disorders and Rehabilitation, Children's Hospital, Boston, MA, USA
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Albagli D, Dark M, Perelman LT, von Rosenberg C, Itzkan I, Feld MS. Photomechanical basis of laser ablation of biological tissue. Opt Lett 1994; 19:1684-1686. [PMID: 19855621 DOI: 10.1364/ol.19.001684] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The photomechanical model of laser ablation of biological tissue asserts that ablation is initiated when the laser-induced tensile stress exceeds the ultimate tensile strength of the target. We show that, unlike the one-dimensional thermoelastic model of laser-induced stress generation that has appeared in the literature, the full three-dimensional solution predicts the development of significant tensile stresses on the surface of the target, precisely where ablation is observed to occur. An interferometric technique has been developed to measure the time-dependent thermoelastic expansion, and the results for subthreshold laser fluences are in precise agreement with the predictions of the three-dimensional model.
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Albagli D, Dark M, von Rosenberg C, Perelman L, Itzkan I, Feld MS. Laser-induced thermoelastic deformation: a three-dimensional solution and its application to the ablation of biological tissue. Med Phys 1994; 21:1323-31. [PMID: 7799877 DOI: 10.1118/1.597202] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Under certain conditions, laser light incident on a target material can induce an explosive removal of some material, a process called laser ablation. The photomechanical model of laser ablation asserts that this process is initiated when the laser-induced stresses exceed the strength of the material in question. Although one-dimensional calculations have shown that short pulsed lasers can create significant transient tensile stresses in target materials, the stresses last for only a few nanoseconds and the spatial location of the peak stresses is not consistent with experimental observations of material failure in biological tissues. Using the theory of elasticity, analytical expressions have been derived for the thermoelastic stresses and deformations in an axially symmetric three-dimensional solid body caused by the absorption of laser light. The full three-dimensional solution includes three stresses, radial, circumferential and shear, which are necessarily absent in the simple one-dimensional solution. These stresses have long-lived components that exist for eight orders of magnitude longer in time than the acoustic transients, an important point when the details of dynamic fracture are considered. Many important qualitative features are revealed including the spatial location of the peak stresses, which is more consistent with experimental observations of failure.
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Affiliation(s)
- D Albagli
- Laser Biomedical Research Center, George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge 02139
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Albagli D, Banish B, Dark M, Janes GS, von Rosenberg C, Perelman L, Itzkan I, Feld MS. Interferometric surface monitoring of biological tissue to study inertially confined ablation. Lasers Surg Med 1994; 14:374-85. [PMID: 8078387 DOI: 10.1002/lsm.1900140410] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
We present results from the application of laser interferometry to the study of short-pulsed laser ablation of biological tissue. The mechanical response of tissue to laser-induced stress is examined under subthreshold conditions to determine its role in initiating the ablation process. A theoretical model is developed to relate this surface displacement to the pressure within the tissue and the mechanical properties of the tissue. In the experiment, a 7.5 ns pulse of 355 nm light was used to irradiate bovine shank bone, human meniscus, and an aqueous dye solution. Interferometric monitoring of the tissue surface was used to determine its motion after laser irradiation. The surface movement of bone was qualitatively consistent with the theoretical predictions of the model. The movement of meniscus and an aqueous dye solution showed additional features that are consistent with the growth and collapse of cavitation bubbles.
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Affiliation(s)
- D Albagli
- Laser Biomedical Research Center, George R. Harrison Spectroscopy Laboratory, Massachusetts Institute of Technology, Cambridge 02139
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Itzkan I, Albagli D, Banish BJ, Dark M, von Rosenberg C, Perelman LT, Janes GS, Feld MS. Pressure generation during inertially confined laser ablation of biological tissue. ACTA ACUST UNITED AC 1993. [DOI: 10.1063/1.44847] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Dark M, Marsh S, Cosgrove G. Mental handicap. Fears unfounded. Nurs Mirror 1985; 161:37-9. [PMID: 3850592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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