A dose-volume analysis of radiation therapy for T1N0 invasive breast cancer treated by local excision and partial breast irradiation by low-dose rate interstitial implant

Abstract

case were generated with two-, three-, and four-fields. Intensity modulated tangential or near tangential 6MV beams were used to minimize low dose scatter to normal tissue, especially lungs. Target coverage and normal tissue dose were compared using dose volume histograms. Results:The extent of interfraction variation is depicted in the composite of all images for a representative patient seen in figure on left. From the composite, the maximum chest wall and breast variation can be measured to be up to 2 cm. The intrafractional movement is depicted in the composite of all images seen in figure on right. The maximum chest wall and breast movement can be measured to be up to 1 cm. The diaphragm motion reached up to 1.5 cm. The 3 and 4 field IMRT plans demonstrated excellent dose distribution with the elimination of multiple fields and junctions, and kept lung dose-volume parameters below our published institutional limits only when internal mammary nodes were not included as a target. Conclusions:The magnitude of interfractional setup error was significantly greater than the intrafractional variation. The magnitude of intrafractional motion was much less than we expected. Interfraction variation indicates a need for improved patient positioning, either with better immobilization or image guided patient setup technology. Intrafraction movement (primarily breathing motion) must also be taken into account in the implementation of IMRT in the treatment of breast cancer patients. IMRT allows elimination of junctions and fewer fields to be used to treat breast cancer.

Accelerated partial breast irradiation using interstitial high dose rate 192iridium brachytherapy: Early Australian experience and review of the literature

“…A joint randomized trial by the NSABP (B‐39) and the RTOG (0413) has recently begun comparing interstitial and EBRT partial volume techniques. Table 2 31–40, 47, 54, 58–60 summarizes current APBI brachytherapy outcomes in over 880 women. Median follow up, however, is short with only three of nine HDRB and two of seven low dose rate studies having a minimum follow up of 5 years.…”

Virtual Planning of Multicatheter Brachytherapy Implants for Accelerated Partial Breast Irradiation

“…Results of this Accelerated Partial Breast Irradiation (APBI) have been very promising [7][8][9][10][11][12][13][14][15]. Traditionally, APBI has been delivered using interstitial radioactive implants (brachytherapy).…”