Seed applicator for use in radiation therapy

An applicator for implanting seeds at spaced locations in a patient's body, comprising:

• a base member adapted to be positioned, during use of the applicator, generally stationary with respect to a surface of the patient's body;
• a needle slidably mounted with respect to the base member and insertable into the patient's body, the needle including a bore extending therethrough;
• a seed magazine for dispensing seeds into the bore of the needle;
• a stylet extendable through the needle bore adapted to force seeds in the bore into the patient's body;
• and
• adjusting means for releasably fixing the needle in at least two sets of variably spaced positions relative to the base member in order to enable seeds to be implanted at variably spaced locations in the patient's body, wherein the adjusting means comprise a barrel attached to the needle, the barrel including at least two series of spaced indentations, the indentations in one series being generally equally spaced by a first distance and the indentations in another series being generally equally spaced by a second distance different than the first distance, the adjusting means also comprising a ball plunger movably mounted in the base member, the ball plunger being successively engageable with the indentations as the barrel is moved with respect to the base member to releasably fix the needle relative to the base member in the variably spaced positions.