A proton therapy system comprising: an accelerator configured to generate a proton beam with an initial energy, wherein said initial energy is within a range between 220 MeV and 230 MeV; and a gantry assembly coupled to said accelerator, wherein a gantry length of said gantry assembly is less than 8m and wherein said gantry assembly is configured to rotate 360°, said gantry assembly comprising: only two dipole magnets (201, 202) consisting in a first dipole magnet and a downstream second dipole magnet, wherein said second dipole magnet is operable to bend said proton beam in a bend radius of approximately 1.5m, and wherein an outer radius of a cross section of said second dipole magnet is approximately 0.36m; five quadrupole magnets, wherein only three (213, 214, 215) of said five quadrupole magnets are disposed between said first dipole magnet and said second dipole magnet; and a scanning nozzle, wherein said scanning nozzle is configured to irradiate said proton beam to an object located proximate to an iso-center of said proton therapy system and wherein said scanning nozzle comprises a pencil beam scanning nozzle disposed downstream of said second dipole magnet; wherein a source-to-axis distance, SAD, of said gantry assembly corresponds to a distance from said scanning nozzle to said iso-center, and wherein said proton therapy system is configured to deliver said proton beam with a beam spot at said iso-center being less than sigma 4 mm and with said SAD being less than or equal to 1.9 m. an accelerator configured to generate a proton beam with an initial energy, wherein said initial energy is within a range between 220 MeV and 230 MeV; and a gantry assembly coupled to said accelerator, wherein a gantry length of said gantry assembly is less than 8m and wherein said gantry assembly is configured to rotate 360°, said gantry assembly comprising: only two dipole magnets (201, 202) consisting in a first dipole magnet and a downstream second dipole magnet, wherein said second dipole magnet is operable to bend said proton beam in a bend radius of approximately 1.5m, and wherein an outer radius of a cross section of said second dipole magnet is approximately 0.36m; five quadrupole magnets, wherein only three (213, 214, 215) of said five quadrupole magnets are disposed between said first dipole magnet and said second dipole magnet; and a scanning nozzle, wherein said scanning nozzle is configured to irradiate said proton beam to an object located proximate to an iso-center of said proton therapy system and wherein said scanning nozzle comprises a pencil beam scanning nozzle disposed downstream of said second dipole magnet; wherein a source-to-axis distance, SAD, of said gantry assembly corresponds to a distance from said scanning nozzle to said iso-center, and wherein said proton therapy system is configured to deliver said proton beam with a beam spot at said iso-center being less than sigma 4 mm and with said SAD being less than or equal to 1.9 m. only two dipole magnets (201, 202) consisting in a first dipole magnet and a downstream second dipole magnet, wherein said second dipole magnet is operable to bend said proton beam in a bend radius of approximately 1.5m, and wherein an outer radius of a cross section of said second dipole magnet is approximately 0.36m; five quadrupole magnets, wherein only three (213, 214, 215) of said five quadrupole magnets are disposed between said first dipole magnet and said second dipole magnet; and a scanning nozzle, wherein said scanning nozzle is configured to irradiate said proton beam to an object located proximate to an iso-center of said proton therapy system and wherein said scanning nozzle comprises a pencil beam scanning nozzle disposed downstream of said second dipole magnet; wherein a source-to-axis distance, SAD, of said gantry assembly corresponds to a distance from said scanning nozzle to said iso-center, and wherein said proton therapy system is configured to deliver said proton beam with a beam spot at said iso-center being less than sigma 4 mm and with said SAD being less than or equal to 1.9 m.