A camera (10;50) comprising: a sensor module which includes an imaging sensor and which is arranged to, on exposure to radiation, measure radiation data for visualizing a state of distribution of radioactive substances; a cooling device; an electrical apparatus (20;51) which is a heat generation part and which is different from the sensor module and which is configured to control the imaging sensor such that the radiation data is measured; and wherein the cooling device includes a heat conducting member which is in thermal contact with the sensor module, a radiator (14-1,14-2) which has a plurality of fins and which is arranged to radiate heat which is generated when the sensor module is cooled; and a fan (15-1,15-2) which is arranged to generate a flow of a first fluid for cooling the radiator (14-1,14-2); characterized in that the camera further comprises: a case (3;55) inside of which the sensor module, the cooling device, and the electrical apparatus (20;51) are disposed; and wherein the case (3;55) has an air intake opening (21-1,21-2) formed in a back surface and the camera (10;50) further includes a partition plate (35,36;52,53) configured to form with the case (3;55) a first passage (41;65) through which the first fluid can flow, a second passage (43;63,64) through which a second fluid for cooling the electrical apparatus (20;51) can flow, and a merging part (44;66,67) which is arranged to suck the second fluid from the second passage (43;63,64) into the first passage (41;65) by means of the flow of the first fluid; and wherein the fan (15-1,15-2) is disposed between the air intake opening (21-1,21-2) and the radiator (14-1,14-2) and wherein the radiator (14-1,14-2) is disposed between the fan (15-1,15-2) and the heat conducting member such that the fan (15-1,15-2) in operation suctions air from the outside of the case (3;55) through the air intake opening (21-1,21-2) and sends the air to the fins of the radiator (14-1,14-2). a sensor module which includes an imaging sensor and which is arranged to, on exposure to radiation, measure radiation data for visualizing a state of distribution of radioactive substances; a cooling device; an electrical apparatus (20;51) which is a heat generation part and which is different from the sensor module and which is configured to control the imaging sensor such that the radiation data is measured; and wherein the cooling device includes a heat conducting member which is in thermal contact with the sensor module, a radiator (14-1,14-2) which has a plurality of fins and which is arranged to radiate heat which is generated when the sensor module is cooled; and a fan (15-1,15-2) which is arranged to generate a flow of a first fluid for cooling the radiator (14-1,14-2); characterized in that the camera further comprises: a case (3;55) inside of which the sensor module, the cooling device, and the electrical apparatus (20;51) are disposed; and wherein the case (3;55) has an air intake opening (21-1,21-2) formed in a back surface and the camera (10;50) further includes a partition plate (35,36;52,53) configured to form with the case (3;55) a first passage (41;65) through which the first fluid can flow, a second passage (43;63,64) through which a second fluid for cooling the electrical apparatus (20;51) can flow, and a merging part (44;66,67) which is arranged to suck the second fluid from the second passage (43;63,64) into the first passage (41;65) by means of the flow of the first fluid; and a case (3;55) inside of which the sensor module, the cooling device, and the electrical apparatus (20;51) are disposed; and wherein the case (3;55) has an air intake opening (21-1,21-2) formed in a back surface and the camera (10;50) further includes a partition plate (35,36;52,53) configured to form with the case (3;55) a first passage (41;65) through which the first fluid can flow, a second passage (43;63,64) through which a second fluid for cooling the electrical apparatus (20;51) can flow, and a merging part (44;66,67) which is arranged to suck the second fluid from the second passage (43;63,64) into the first passage (41;65) by means of the flow of the first fluid; and wherein the fan (15-1,15-2) is disposed between the air intake opening (21-1,21-2) and the radiator (14-1,14-2) and wherein the radiator (14-1,14-2) is disposed between the fan (15-1,15-2) and the heat conducting member such that the fan (15-1,15-2) in operation suctions air from the outside of the case (3;55) through the air intake opening (21-1,21-2) and sends the air to the fins of the radiator (14-1,14-2).