Methods for asymmetrical irradiation of a body cavity
The disclosure describes devices and methods for asymmetrical irradiation at a body cavity or site, such as after removal of tissue, e.g. biopsy or cancer. One device includes a lumen which is off-set or off-settable from a longitudinal axis to increase the intensity of radiation received from a radiation source by a first tissue portion surrounding the body cavity and to reduce or minimize radiation received by a second tissue portion (e.g. healthy tissue) surrounding the body cavity.
1. A method of delivering radiation therapy to tissue around at least a portion of a cavity formed by tissue removal in a patient's breast, comprising:
a) providing a brachytherapy device, comprising:
i. an elongated shaft having a distal shaft portion with a central longitudinal axis,
ii. three radiation source guides which have lumens configured to receive a radiation source therein, which are at least in part spaced away from a central longitudinal axis, said spaced away parts being uniformly distributed about the central longitudinal axis and
iii. an expandable member which has a contracted configuration and an expanded configuration and which is disposed about the three radiation source guides;
b. providing a single radiation source;
c. inserting the brachtherapy device into the patient with the expandable member in the contracted configuration until the distal shaft portion is disposed in the body cavity formed in the patient's breast;
d. expanding the expandable member within the body cavity to the expanded configuration;
e. inserting the single radiation source into the inner lumen of a first of the three radiation source guides, advancing the single radiation source to a first position within the lumen of the first radiation source guide spaced from the central longitudinal axis, holding the single radiation source at the first position for a first preselected time period and then withdrawing the single radiation source from the inner lumen of the first guide after the first preselected time period; and
f. inserting the single radiation source into the inner lumen of a second of the three radiation source guides and advancing the single radiation source to a second position within the lumen of the second radiation source guide, holding the single radiation source at the second position for a second preselected time period and withdrawing the single radiation source from the inner lumen of the second guide after the second preselected time period.
2. The method of claim 1 wherein the single radiation source is inserted into the inner lumen of a third of the three radiation source guides and is advanced to a third position within the lumen of the third radiation source guide, holding the single radiation source at the third position for a third preselected time period and withdrawing the single radiation source from the inner lumen of the third guide after the third preselected time period.
3. The method of claim 1 wherein the brachytherapy device has guide which is concentric with the central longitudinal axis and has a lumen configured to receive the single radiation source therein and the single radiation source is inserted into the lumen of the concentric guide and advanced to a position therein, held at that position for a preselected time period and then withdrawn from the lumen of the concentric guide after the preselected time period.
4. The method of claim 1 wherein the expandable member is expanded so as to be spaced away from the three radiation source guides.
5. The method of claim 4 wherein the expandable member is a balloon.