Patent Number: 
Section: claims

1. A shielding for reducing the amount of radiation passing through the shielding, the shielding comprising a first part and a second part, the first part configured to be withdrawn from the second part and said first and second parts comprising abutments which face each other, at least one pair of facing abutments of said first and second parts has a transverse section, the section comprising a curvilinearly shaped portion which nests into an opposite curvilinear portion. 2. The shielding according to claim 1, wherein said portion extends along at least 60% of said section. 3. The shielding according to claim 1 or 2, wherein the radius of curvature of the curvilinear shape of said portion is constant. 4. The shielding according to claim 1, wherein at least said portion shows a value of the radius of curvature different from zero. 5. The shielding according to claim 1, comprising a shell that can be filled with radiation absorbing material. 6. The shielding according to claim 5, wherein said shell comprises an outer region that can be filled with a high Z compound and an inner region that can be filled with a low Z compound. 7. The shielding according to claim 6, wherein said high Z compound comprises lead or iron. 8. The shielding according to claim 6, wherein said low Z compound comprises a polyethylene or paraffin compound. 9. The shielding according to claim 1, the shielding configured to shield radiation produced by a radiation source and wherein said shielding is provided at an outer side of said source. 10. The shielding according to claim 9, wherein said radiation source is a cyclotron. 11. The shielding according to claim 10, wherein said cyclotron comprises a target and an additional high Z material shield in front of said target. 12. The shielding according to claim 1, further comprising wheels configured to displace said first part and/or said second part. 13. The shielding according to claim 12, further comprising a lifting mechanism for said wheels. 14. The shielding according to claim 12, wherein said first part is a lid or a door configured to fit in an opening of said second part. 15. The shielding according to claim 1, wherein said second part is a container configured to limit the exit of radiation from a radiation source in the container. 16. The shielding according to claim 1, wherein said curvilinear portion extends along at least 70% of said section. 17. A method for reducing the amount of radiation passing through a shielding, the method comprising the steps of:providing a shielding comprising a first part and a second part, said first part and said second part comprising abutments andshaping corresponding abutments of the first and second parts curvilinearly along a major portion of a transverse section of said abutments.