TY - JOUR
T1 - Proton partial breast irradiation in the supine position
T2 - Treatment description and reproducibility of a multibeam technique
AU - Strom, Eric A.
AU - Amos, Richard A.
AU - Shaitelman, Simona F.
AU - Kerr, Matthew D.
AU - Hoffman, Karen E.
AU - Smith, Benjamin D.
AU - Tereffe, Welela
AU - Stauder, Michael C.
AU - Perkins, George H.
AU - Amin, Mayankumar D.
AU - Wang, Xiaochun
AU - Poenisch, Falk
AU - Ovalle, Valentina
AU - Buchholz, Thomas A.
AU - Babiera, Gildy
AU - Woodward, Wendy A.
N1 - Publisher Copyright:
© 2015 American Society for Radiation Oncology.
PY - 2015
Y1 - 2015
N2 - Purpose: Proton-accelerated partial breast irradiation (APBI) is early in its developmental phase without standardized treatment parameters. We report an approach to multibeam proton APBI using a universally available supine setup and deliberate beam arrangement strategy to limit the total area of skin receiving a full dose while being robust for interfraction variation. Methods and materials: Thirty-three American Society for Radiation Oncology consensus-suitable/cautionary APBI candidates were treated using a passively scattered proton beam between 2010 and 2014 to 34 Gy relative biological effectiveness in 10 fractions twice daily. All patients were immobilized in a Vac-Lok cradle, typically with the arm down, and adducted to mound the breast and facilitate multiple, optimal en face beams. Radiopaque wires were placed on the surgical scar and 3 markers separate from the scar were placed elsewhere on the breast. All markers were used for each setup and removed before treatment. Marker displacement, wire rotation, and wire displacement were recorded from 10 random patients (100 orthogonal films). A 15-mm expansion was made to the tumor bed to obtain a clinical target volume, and followed by a 5-mm skin contraction and exclusion of the chest wall. A radial planning target volume margin of 5 mm was used. Results: Across 100 pretreatment images, median displacement of 3 distinct skin set-up markers was 3, 4, and 3 mm. Displacement of the scar wire in the X and Y direction was 0 and 1 mm, respectively. Among 28 verification scans performed, only 1 resulted in adaptive planning because of the initial presence of an air pocket in the lumpectomy cavity that resolved spontaneously during treatment. Conclusions: APBI proton treatment using a supine approach was largely reproducible. Inter-fraction variation demonstrates 5-mm radial planning margins were adequate; however, outliers do occur and films should be reviewed critically and in real time. This technique is straightforward and could be used at any proton facility without the need for specialized equipment.
AB - Purpose: Proton-accelerated partial breast irradiation (APBI) is early in its developmental phase without standardized treatment parameters. We report an approach to multibeam proton APBI using a universally available supine setup and deliberate beam arrangement strategy to limit the total area of skin receiving a full dose while being robust for interfraction variation. Methods and materials: Thirty-three American Society for Radiation Oncology consensus-suitable/cautionary APBI candidates were treated using a passively scattered proton beam between 2010 and 2014 to 34 Gy relative biological effectiveness in 10 fractions twice daily. All patients were immobilized in a Vac-Lok cradle, typically with the arm down, and adducted to mound the breast and facilitate multiple, optimal en face beams. Radiopaque wires were placed on the surgical scar and 3 markers separate from the scar were placed elsewhere on the breast. All markers were used for each setup and removed before treatment. Marker displacement, wire rotation, and wire displacement were recorded from 10 random patients (100 orthogonal films). A 15-mm expansion was made to the tumor bed to obtain a clinical target volume, and followed by a 5-mm skin contraction and exclusion of the chest wall. A radial planning target volume margin of 5 mm was used. Results: Across 100 pretreatment images, median displacement of 3 distinct skin set-up markers was 3, 4, and 3 mm. Displacement of the scar wire in the X and Y direction was 0 and 1 mm, respectively. Among 28 verification scans performed, only 1 resulted in adaptive planning because of the initial presence of an air pocket in the lumpectomy cavity that resolved spontaneously during treatment. Conclusions: APBI proton treatment using a supine approach was largely reproducible. Inter-fraction variation demonstrates 5-mm radial planning margins were adequate; however, outliers do occur and films should be reviewed critically and in real time. This technique is straightforward and could be used at any proton facility without the need for specialized equipment.
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U2 - 10.1016/j.prro.2015.01.010
DO - 10.1016/j.prro.2015.01.010
M3 - Article
C2 - 25804105
AN - SCOPUS:84937163013
SN - 1879-8500
VL - 5
SP - e283-e290
JO - Practical radiation oncology
JF - Practical radiation oncology
IS - 4
ER -