Brachytherapy device having seed tubes with individually-settable tissue spacings

1. A brachytherapy device comprising a plurality of rods, each configured to move between a straightened position and a bowed position, the plurality of rods configured to collectively form a shaft while each rod is in the straightened position and to collectively form at least one cage while at least some of the rods are in the bowed position, at least some of the rods having lumens that are configured to receive and hold radioactive material, wherein some of the rods are configured to form a first cylinder while in the straightened position and the other rods are configured to form a second cylinder while in the straightened position that surrounds the first cylinder, whereby the plurality of rods are further configured such that at least a substantial portion of each rod in the second cylinder lies between two rods within the first cylinder while in the straightened position.

2. The brachytherapy device of claim 1 further comprising a rotatable mechanism configured to move the second cylinder between the straightened position and the bowed position.

3. A brachytherapy device comprising a plurality of rods, each configured to move between a straightened position and a bowed position, the plurality of rods configured to collectively form a shaft while each rod is in the straightened position and to collectively form at least one cage while at least some of the rods are in the bowed position, at least some of the rods having lumens that are configured to receive and hold radioactive material, wherein each rod has opposing longitudinal flanges, each of which is configured to overlap with a longitudinal flange of a neighboring rod while in the straightened position.

4. The brachytherapy device of claim 3 further comprising a rotatable mechanism configured to move some of the rods between the straightened position and the bowed position.

5. A brachytherapy device comprising:

a first and a second set of rods, at least some of the rods having lumens that are configured to receive and hold radioactive material;

a group expansion mechanism associated with the first set of rods and configure to collectively move the first set of rods in unison, each between a straightened position and a bowed position, the first set of rods configured to collectively form a shaft while each of the first set of rods is in the straightened position and to collectively form a cage while each of the first set of rods is in the bowed position; and

a rod bowing mechanism associated with each of the second set of rods and configured to individually move each of the second set of rods between a straightened and a bowed position, the second set of rods configured to collectively form a shaft while each of the second set of rods is in the straightened position.

6. The brachytherapy device of claim 5 wherein the group expansion mechanism includes a rotatable mechanism configured to move the first set of rods in unison between the straightened position and the bowed position.

7. A brachytherapy device comprising:

a plurality of rods configured to move between a straightened position and a bowed position, the rods configured to collectively form a shaft while each of the rods is in the straightened position, at least some of the rods having lumens configured to receive and hold radioactive material; and

a plurality of actuators, each associate with one of the rods and configured to cause the rod with which it is associated to move from the straightened position to the bowed position in incremental steps, each of the incremental steps being delineated by a ratchet mechanism.