Implant with fiducial markers

1. An implant assembly comprising:

a first implant comprising:

a first body made of a flexible and non-bioresorbable hydrogel material, the first body having a first shape; and

a first marker located at least partially within the first body, the first marker made of a radiopaque material, and the first body and the first marker implantable in a body cavity to mark the cavity in a radiographic image of the cavity; and

a second implant comprising:

a second body made of the flexible and non-bioresorbable hydrogel material, the second body having a second shape; and

a second marker located at least partially within the second body, the second marker made of a radiopaque material, and the second body and the second marker implantable in the body cavity to mark the cavity in a radiographic image of the cavity,

wherein the first shape and the second shape are the same shape or are different shapes,

wherein the first shape and the second shape are the same size or are different sizes,

wherein the first body and the second body have geometric shapes of spheres and wherein the first body defines a first diameter and the second body defines a second diameter, and

wherein the second diameter is smaller than the first diameter.

2. The implant assembly of claim 1 , wherein the second diameter is less than half of the first diameter.

3. The implant assembly of claim 1 , wherein the first implant and the second implant are positionable to fill the cavity when the cavity has an irregular shape.

4. The implant assembly of claim 1 , wherein a modulus of elasticity of the hydrogel of the first body and the second body is between 0.5 and 25 kilopascals.

5. An implant assembly comprising:

an implant comprising one or more selectable implant bodies, the implant comprising:

an implant body made of a flexible and non-bioresorbable hydrogel; and

a marker located within the implant body, the marker made of a radiopaque material, the implant body bearing the marker being implantable in a breast cavity to mark the cavity in a radiographic image of the cavity; and

an introducer comprising an elongate tube insertable into a body cavity and operable to receive the implant body therethrough to guide the implant body into the body cavity;

wherein the implant comprises a plurality of implant bodies selectable from the plurality of implant bodies, wherein a first quantity of the plurality of implant bodies define a first diameter and wherein a second quantity of the implant bodies define a second diameter that is smaller than the first diameter.

6. The implant assembly of claim 5 , further comprising:

a stylet insertable into the introducer and operable to engage the implant to position the implant body within the body cavity.

7. The implant assembly of claim 6 , wherein the stylet has a length that is longer than a length of the introducer.

8. The implant of claim 5 , further comprising:

a dehydrated hydrogel layer located on and connected to an exterior surface of the implant body, the dehydrated hydrogel layer to expand within the body cavity following implantation thereof.

9. An implant assembly comprising:

a first implant comprising:

a first body made of a flexible and non-bioresorbable hydrogel material, the first body having a first shape, and the first body defining a first diameter; and

a first marker located at least partially within the first body, the first marker made of a radiopaque material, and the first body and the first marker implantable in a body cavity to mark the cavity in a radiographic image of the cavity; and

a second implant comprising:

a second body made of the flexible and non-bioresorbable hydrogel material, the second body having a second shape, the first body and the second body having geometric shapes of spheres, and the second body defining a second diameter that is smaller than the first diameter; and

a second marker located at least partially within the second body, the second marker made of a radiopaque material, and the second body and the second marker implantable in the body cavity to mark the cavity in a radiographic image of the cavity.

10. The implant assembly of claim 9 , wherein the second diameter is less than half of the first diameter.

11. The implant assembly of claim 9 , wherein the first implant and the second implant are positionable to fill the cavity when the cavity has an irregular shape.

12. The implant assembly of claim 9 , wherein a modulus of elasticity of the hydrogel of the first body and the second body is between 0.5 and 25 kilopascals.