A multifunction gamma radiation detector comprising: - a supporting rod; - a detection head coupled or integrated with a first end of said supporting rod and comprising a plurality of detection elements (21a, 21b, 21c) which are separate from each other for simultaneously detecting gamma radiation, each detection element (21a, 21b, 21c) comprising at least one scintillation crystal and a corresponding first electronic conversion circuitry for receiving an optical signal from the crystal and converting it into an electrical signal, each of said detection elements (21a, 21b, 21c) being suitable to screen the gamma radiation striking said detection element (21a, 21b, 21c) with a external angle and a predetermined solid angle (α, β, γ); - a handgrip connected or connectable to a second end of the supporting rod and which can be gripped manually by an operator for directing said detector; - a second electronic circuitry for converting and/or treating the signals, preferably positioned inside the handgrip, connected to said first electronic conversion device for processing the electrical signal generated by the first electronic conversion circuitry; said detection head further comprises at least one optical detection device configured to acquire a sequence of optical signals emitted by a suitably energised body tissue, said detection elements (21a, 21b, 21c) are angularly distributed on the detection head about said at least one optical detection device and characterized in that said plurality of detection elements (21a, 21b, 21c) detect gamma radiation directed along respective directions different to each other, and in that each of said detection elements (21a, 21b, 21c) is associated with a respective collimator made of a material with a high atomic number, and in that said detection elements (21a, 21B, 21c) define respective solid detection angles (α, β, γ) shaped and/or oriented in such a way as to define between them a blind zone outside the solid detection angles (α, β, γ), said blind zone having a length having a minimum value that is approximately equal to 5 mm and a maximum value that is approximately equal to 50 mm. - a supporting rod; - a detection head coupled or integrated with a first end of said supporting rod and comprising a plurality of detection elements (21a, 21b, 21c) which are separate from each other for simultaneously detecting gamma radiation, each detection element (21a, 21b, 21c) comprising at least one scintillation crystal and a corresponding first electronic conversion circuitry for receiving an optical signal from the crystal and converting it into an electrical signal, each of said detection elements (21a, 21b, 21c) being suitable to screen the gamma radiation striking said detection element (21a, 21b, 21c) with a external angle and a predetermined solid angle (α, β, γ); - a handgrip connected or connectable to a second end of the supporting rod and which can be gripped manually by an operator for directing said detector; - a second electronic circuitry for converting and/or treating the signals, preferably positioned inside the handgrip, connected to said first electronic conversion device for processing the electrical signal generated by the first electronic conversion circuitry; said detection head further comprises at least one optical detection device configured to acquire a sequence of optical signals emitted by a suitably energised body tissue, said detection elements (21a, 21b, 21c) are angularly distributed on the detection head about said at least one optical detection device and characterized in that said plurality of detection elements (21a, 21b, 21c) detect gamma radiation directed along respective directions different to each other, and in that each of said detection elements (21a, 21b, 21c) is associated with a respective collimator made of a material with a high atomic number, and in that said detection elements (21a, 21B, 21c) define respective solid detection angles (α, β, γ) shaped and/or oriented in such a way as to define between them a blind zone outside the solid detection angles (α, β, γ), said blind zone having a length having a minimum value that is approximately equal to 5 mm and a maximum value that is approximately equal to 50 mm.