# US 9,433,355 B2 · Photoacoustic imaging apparatus and photoacoustic imaging method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,433,355 B2 - Document ID: US9433355B2 - Status: Granted - Kind: B2 - Application number: 13/634,741 - Filed: 2011-04-19 - Published: 2013-01-03 - Granted: 2016-09-06 - Earliest claimed: 2010-04-28 - Assignees: Canon Kabushiki Kaisha - Applicants: Takuro Miyasato - Inventors: Takuro Miyasato - Web page: https://patentgrep.com/patent/US9433355B2 ## CPC - A61B 5/0095: {by applying light and detecting acoustic waves, i.e. photoacoustic measurements} - A61B 5/0091: {for mammography} - A61B 5/4312: {Breast evaluation or disorder diagnosis (optical mammography A61B5/0091)} - A61B 5/708: {Breast positioning means} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A photoacoustic imaging apparatus includes holding members configured to hold a subject, an acoustic wave conversion unit configured to receive an acoustic wave generated by irradiating the subject, which is held by the holding members, with light from a light source and convert the acoustic wave into an electric signal, a processing unit configured to generate image data from the electric signal, and an imaging unit configured to capture an optical pattern generated on a light diffusion member by emitting the light to the light diffusion member arranged on a surface of a side where the subject is irradiated with the light in the holding members where the holding members contact the subject in holding the subject, wherein the processing unit calculates light absorption coefficient distribution in the subject based on the optical pattern captured by the imaging unit and the electric signal acquired by the acoustic wave conversion unit. ## Claims ### Claim 1 A photoacoustic imaging apparatus comprising: a light source configured to emit first light and second light; a light diffusion member; a light amount measurement unit configured to measure a light amount of a part of the first light emitted from the light source; an acoustic wave conversion unit configured to receive an acoustic wave generated by irradiating a subject with the first light and convert the acoustic wave into an electric signal; a processing unit configured to generate image data based on the electric signal; and an imaging unit configured to capture an optical pattern of the second light on the light diffusion member, the optical pattern being generated by irradiating the light diffusion member with the second light, wherein the first light is light emitted by the light source to irradiate the subject, and the second light is light emitted by the light source to irradiate the diffusion member without irradiating the subject, wherein the processing unit is configured to calculate relative light irradiation density distribution of the second light based on the optical pattern of the second light captured by the imaging unit, wherein the processing unit is configured to calculate light irradiation density distribution of the first light based on the relative light irradiation density distribution of the second light calculated by the processing unit and the light amount of the part of the first light measured by the light amount measurement unit, wherein the processing unit is configured to calculate light amount distribution of the first light in the subject based on the light irradiation density distribution of the first light calculated by the processing unit, and wherein the processing unit is configured to generate image data of a light absorption coefficient distribution in the subject based on the light amount distribution of the first light in the subject and the electric signal. ### Claim 2 (depends on 1) The photoacoustic imaging apparatus according to claim 1, wherein the processing unit is configured to control the light source so that a maximum value of the light irradiation density distribution of the first light is less than or equal to a maximum permissible exposure amount for the subject. ### Claim 3 (depends on 1) The photoacoustic imaging apparatus according to claim 1, wherein the light source is a laser generator. ### Claim 4 (depends on 1) The photoacoustic imaging apparatus according to claim 1, further comprising a holding members configured to hold the subject by contacting the subject, wherein the light diffusion member is arranged on the holding member. ### Claim 5 (depends on 1) The photoacoustic imaging apparatus according to claim 1, further comprising: an optical system configured to lead light from the light source to the subject and to the light diffusion member. ### Claim 6 (depends on 1) The photoacoustic imaging apparatus according to claim 1, wherein the light diffusion member is configured to be removed from the photoacoustic imaging apparatus. ### Claim 7 (depends on 1) The photoacoustic imaging apparatus according to claim 1, wherein the light amount measurement unit includes one of an optical sensor, a thermal sensor, and a pyroelectric sensor. ### Claim 8 (depends on 1) The photoacoustic imaging apparatus according to claim 1, wherein the imaging unit includes plural elements configured to detect light. ### Claim 9 (depends on 1) The photoacoustic imaging apparatus according to claim 1, wherein a thickness of the light diffusion member is from 0.1 mm to 1.0 mm. ### Claim 10 A photoacoustic imaging method comprising: irradiating a subject with first light; measuring a light amount of a part of the first light; converting an acoustic wave generated by the irradiating the subject with the first light into an electric signal; irradiating a light diffusion member with second light, wherein the first light is light emitted by a light source to irradiate the subject, and the second light is light emitted by the light source to irradiate the diffusion member without irradiating the subject; capturing an optical pattern of the second light generated on the light diffusion member; calculating relative light irradiation density distribution of the second light based on the optical pattern of the second light; calculating light irradiation density distribution of the first light based on the relative light irradiation density distribution of the second light and the light amount of a part of the first light, calculating light amount distribution of the first light in the subject based on the light irradiation density distribution of the first light, and generating light image data of absorption coefficient distribution in the subject based on the light amount distribution of the first light in the subject and the electric signal. ### Claim 11 (depends on 10) The photoacoustic imaging method according to claim 10, further comprising determining whether a maximum value of the light irradiation density distribution of the first light is less than or equal to a maximum permissible exposure amount for the subject. ### Claim 12 (depends on 11) The photoacoustic imaging method according to claim 11, further comprising controlling the light source that emits the first light so that the maximum value of the light irradiation density distribution of the first light becomes less than or equal to the maximum permissible exposure amount if the maximum value of the light irradiation density distribution of the first light is not less than the maximum permissible exposure amount for the subject. ### Claim 13 (depends on 10) The photoacoustic imaging method according to claim 10, further comprising controlling a light source that emits the first light so that a maximum value of the light irradiation density distribution of the first light is less than or equal to a maximum permissible exposure amount for the subject.