Radiation shields for brachytherapy
A shield assembly for an intensity modulated brachytherapy (IMBT) system, has: a tubular applicator engageable to a rotating mechanism of the IMBT system, the tubular applicator having a peripheral wall enclosing an internal cavity extending longitudinally along a central axis; a radiation shield extending axially along the central axis and received within the internal cavity, the radiation shield made of an MRI-compatible and radiation attenuating material; and a radionuclide-receiving passage within the internal cavity of the tubular applicator, the radionuclide-receiving passage extending axially and being radially offset from the central axis.
1. A shield assembly for an intensity modulated brachytherapy (IMBT) system, comprising:
a tubular applicator engageable to a rotating mechanism of the IMBT system, the tubular applicator having a peripheral wall enclosing an internal cavity extending longitudinally along a central axis;
a radiation shield extending axially along the central axis and received within the internal cavity, the radiation shield made of an MRI-compatible and radiation attenuating material, the radiation shield including radiation shield sections interconnected to one another and pivotable one relative to the other about axes transverse to the central axis, the radiation shield sections are interconnected to one another by joints, the joints permitting rotation about the axes and preventing the radiation shield sections from translating one relative to the other along the central axis, a joint of the joints including:
a ball protruding axially from an axial end face of one of the radiation shield sections and a rounded cavity extending from an axial end face of an adjacent one of the radiation shield sections, the ball received within the rounded cavity, or
a tab protruding from an axial end face of one of the radiation shield sections and a recess extending from the axial end face of an adjacent one of the radiation shield sections, the tab pivotably received within the recess, the tab locked within the recess via a pin extending through a first aperture defined through the tab and through a second aperture defined through the adjacent one of the radiation shield sections; and
a radionuclide-receiving passage within the internal cavity of the tubular applicator, the radionuclide-receiving passage extending axially and being radially offset from the central axis.
2. The shield assembly of claim 1 , wherein the central axis is free of intersection with the radionuclide-receiving passage.
3. The shield assembly of claim 1 , wherein the radionuclide-receiving passage is a groove defined by the radiation shield and extending axially along the central axis, the groove extending radially from an outer face of the radiation shield toward the central axis.
4. The shield assembly of claim 1 , wherein the radionuclide-receiving passage is defined between a cylindrical outer face of the radiation shield and the peripheral wall.
5. The shield assembly of claim 1 , wherein the radionuclide-receiving passage is a bore extending through the radiation shield.
6. The shield assembly of claim 5 , wherein the radiation shield defines apertures extending from an outer surface of the radiation shield to the bore, the apertures axially spaced-apart from one another along the central axis and being circumferentially aligned with one another.
7. The shield assembly of claim 5 , wherein a ratio of a distance (D3) between a center of the bore and a center of the radiation shield to an internal diameter (D8) of the tubular applicator ranges from 0.06 to 0.2.
8. The shield assembly of claim 7 , wherein a ratio of a diameter (D7) of the bore to a the internal diameter (D8) of the tubular applicator ranges from 0.09 to 0.3, wherein a ratio of a distance (d 3 ) taken along the central axis between two adjacent ones of the apertures to the internal diameter of the tubular applicator ranges from 0.6 to 2, and wherein a ratio of a diameter (D4) of the apertures to the internal diameter (D8) of the tubular applicator ranges from 0.06 to 0.2.
9. An intensity modulated brachytherapy (IMBT) system, comprising a rotating system and a shield assembly drivingly engaged to the rotating system for rotating the shield assembly about a central axis thereof, the shield assembly having: a tubular applicator including a peripheral wall enclosing an internal cavity extending axially along the central axis; a radiation shield within the internal cavity and extending axially along the central axis, the radiation shield made of an MRI-compatible and radiation attenuating material; and a radionuclide-receiving passage within the internal cavity of the tubular applicator, the radionuclide-receiving passage being eccentric relative to the internal cavity of the tubular applicator, the radiation shield defining apertures extending from an outer surface of the radiation shield to the radionuclide-receiving passage, the apertures axially spaced-apart from one another along the central axis and being circumferentially aligned with one another, the apertures located at a single circumferential position relative to the central axis, the radiation shield devoid of apertures outside the single circumferential position, wherein the radiation shield includes: radiation shield sections interconnected to one another and pivotable one relative to the other about an axis normal to the central axis; and a monolithic body defining a flexible section, the flexible section including a plurality of slits, each of the slits extending from an outer face of the monolithic body toward the central axis, the slits ending at a core, discs defined between the slits and being axially spaced apart from one another to allow bending of the core.
10. The IMBT system of claim 9 , wherein the peripheral wall defines a slit pattern.
11. The IMBT system of claim 10 , wherein slits of the slit pattern have a jigsaw shape or a helicoid shape.
12. The IMBT system of claim 9 , wherein the radiation shield sections are interconnected to one another by a joint.
13. The IMBT system of claim 12 , wherein the joint includes a ball protruding axially from an axial end face of one of the radiation shield sections and a rounded cavity extending from an axial end face of an adjacent one of the radiation shield sections, the ball received within the rounded cavity.
14. The IMBT system of claim 12 , wherein the joint includes a tab protruding from an axial end face of one of the radiation shield sections and a recess extending from the axial end face of an adjacent one of the radiation shield sections, the tab pivotably received within the recess, the tab locked within the recess via a pin extending through a first aperture defined through the tab and through a second aperture defined through the adjacent one of the radiation shield sections.
15. The IMBT system of claim 9 , wherein the radiation shield sections are connected to one another via flexible rods extending through registering apertures defined by the radiation shield sections.
16. A shield assembly for an intensity modulated brachytherapy (IMBT) system, comprising:
a tubular applicator engageable to a rotating mechanism of the IMBT system, the tubular applicator having a peripheral wall enclosing an internal cavity extending longitudinally along a central axis;
a radiation shield extending axially along the central axis and received within the internal cavity, the radiation shield made of an MRI-compatible and radiation attenuating material, the radiation shield including shield sections interconnected to one another via a core, the core being flexible, the shield sections pivotable one relative to the other about axes transverse to the central axis via flexion of the core; and
a radionuclide-receiving passage within the internal cavity of the tubular applicator, the radionuclide-receiving passage extending axially and being radially offset from the central axis.
17. The shield assembly of claim 16 , wherein the core and the shield sections are parts of a monolithic body of the radiation shield, the shield sections interspaced between slits, each of the slits extending from an outer face of the monolithic body toward the central axis, the slits ending at the core, the shield sections being discs defined between the slits and being axially spaced apart from one another to allow bending of the core.
18. The shield assembly of claim 16 , wherein the core is defined by a flexible rod extending through registering apertures defined by the shield sections.