Aim
We introduce and characterize a dual-modality PA and FL imaging platform using in vivo and phantom experiments. Approach: The imaging platform's detection limits were characterized through phantom studies that determined the PA spatial resolution, PA sensitivity, optical spatial resolution, and FL sensitivity.
Conclusions
The combined PA and FL imaging system has been characterized and has demonstrated its ability to image mice in vivo, proving its suitability for biomedical imaging research applications.
Results
The system characterization yielded a PA spatial resolution of 173±17μm173±17μm<math><mrow><mn>173</mn> <mo>±</mo> <mn>17</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the transverse plane and 640±120μm640±120μm<math><mrow><mn>640</mn> <mo>±</mo> <mn>120</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the longitudinal axis, a PA sensitivity detection limit not less than that of a sample with absorption coefficient μa=0.258cm−1μa=0.258cm-1<math> <mrow> <msub><mrow><mi>μ</mi></mrow> <mrow><mi>a</mi></mrow> </msub> <mo>=</mo> <mn>0.258</mn> <mtext> </mtext> <msup><mrow><mi>cm</mi></mrow> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> </mrow> </math> , an optical spatial resolution of 70μm70μm<math><mrow><mn>70</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the vertical axis and 112μm112μm<math><mrow><mn>112</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the horizontal axis, and a FL sensitivity detection limit not <0.9μM<0.9μM<math><mrow><mo><</mo> <mn>0.9</mn> <mtext> </mtext> <mi>μ</mi> <mi>M</mi></mrow> </math> concentration of IR-800. The scanned animals displayed in three-dimensional renders showed high-resolution anatomical detail of organs. Conclusions: The combined PA and FL imaging system has been characterized and has demonstrated its ability to image mice in vivo, proving its suitability for biomedical imaging research applications.
Significance
To effectively study preclinical animal models, medical imaging technology must be developed with a high enough resolution and sensitivity to perform anatomical, functional, and molecular assessments. Photoacoustic (PA) tomography provides high resolution and specificity, and fluorescence (FL) molecular tomography provides high sensitivity; the combination of these imaging modes will enable a wide range of research applications to be studied in small animals. Aim: We introduce and characterize a dual-modality PA and FL imaging platform using in vivo and phantom experiments. Approach: The imaging platform's detection limits were characterized through phantom studies that determined the PA spatial resolution, PA sensitivity, optical spatial resolution, and FL sensitivity. Results: The system characterization yielded a PA spatial resolution of 173±17μm173±17μm<math><mrow><mn>173</mn> <mo>±</mo> <mn>17</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the transverse plane and 640±120μm640±120μm<math><mrow><mn>640</mn> <mo>±</mo> <mn>120</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the longitudinal axis, a PA sensitivity detection limit not less than that of a sample with absorption coefficient μa=0.258cm−1μa=0.258cm-1<math> <mrow> <msub><mrow><mi>μ</mi></mrow> <mrow><mi>a</mi></mrow> </msub> <mo>=</mo> <mn>0.258</mn> <mtext> </mtext> <msup><mrow><mi>cm</mi></mrow> <mrow><mo>-</mo> <mn>1</mn></mrow> </msup> </mrow> </math> , an optical spatial resolution of 70μm70μm<math><mrow><mn>70</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the vertical axis and 112μm112μm<math><mrow><mn>112</mn> <mtext> </mtext> <mi>μ</mi> <mi>m</mi></mrow> </math> in the horizontal axis, and a FL sensitivity detection limit not <0.9μM<0.9μM<math><mrow><mo><</mo> <mn>0.9</mn> <mtext> </mtext> <mi>μ</mi> <mi>M</mi></mrow> </math> concentration of IR-800. The scanned animals displayed in three-dimensional renders showed high-resolution anatomical detail of organs. Conclusions: The combined PA and FL imaging system has been characterized and has demonstrated its ability to image mice in vivo, proving its suitability for biomedical imaging research applications.