TY - JOUR
T1 - Dosimetric properties of a novel brachytherapy balloon applicator for the treatment of malignant brain-tumor resection-cavity margins
AU - Dempsey, James F.
AU - Williams, Jeffery A.
AU - Stubbs, James B.
AU - Patrick, Timothy J.
AU - Williamson, Jeffrey F.
N1 - Funding Information:
Acknowledgment—This study was supported by a research grant from Proxima Therapeutics Inc. (Formerly Oncocath Inc.).
PY - 1998/9/1
Y1 - 1998/9/1
N2 - Purpose: This paper characterizes the dosimetric properties of a novel balloon brachytherapy applicator for the treatment of the tissue surrounding the resection cavity of a malignant brain tumor. Methods and Materials: The applicator consists of an inflatable silicone balloon reservoir attached to a positionable catheter that is intraoperatively implanted into the resection cavity and postoperatively filled with a liquid radionuclide solution. A simple dosimetric model, valid in homogeneous media and based on results from Monte Carlo photon-transport simulations, was used to determined the dosimetric characteristics of spherical geometry balloons filled with photon- emitting radionuclide solutions. Fractional depth-dose (FDD) profiles, along with activity densities, and total activities needed to achieve specified does rates were studied as a function of photon energy and source-containment geometry. Dose-volume histograms (DVHs) were calculated to compare idealized balloon-applicator treatments to conventional 125I seed volume implants. Results: For achievable activity densities and total activities, classical low dose rate (LDR) treatments of residual disease at distances of up to 1 cm from the resection cavity wall are possible with balloon applicators having radii between 0.5 cm and 2.5 cm. The dose penetration of these applicators increases approximately linearly with balloon radius. The FDD profile can be made significantly more or less penetrating by combining selection of radionuclide with source-geometry manipulation. Comparisons with 125I seed-implant DVHs show that the applicator can provide a more conformal therapy with no target tissue underdosing, less target tissue overdosing, and no healthy tissue 'host spots;' however, more healthy tissue volume receives a dose of the prescribed dosage or less. Conclusions: This device, when filled with 125I solution, is suitable for classical LDR treatments and may be preferable to 125I interstitial-seed implants in several respects. Manipulation of the dosimetric properties of the device can improve its characteristics for brain tumor treatment and may make it suitable for boosting the lumpectomy margins in conservative breast cancer treatment.
AB - Purpose: This paper characterizes the dosimetric properties of a novel balloon brachytherapy applicator for the treatment of the tissue surrounding the resection cavity of a malignant brain tumor. Methods and Materials: The applicator consists of an inflatable silicone balloon reservoir attached to a positionable catheter that is intraoperatively implanted into the resection cavity and postoperatively filled with a liquid radionuclide solution. A simple dosimetric model, valid in homogeneous media and based on results from Monte Carlo photon-transport simulations, was used to determined the dosimetric characteristics of spherical geometry balloons filled with photon- emitting radionuclide solutions. Fractional depth-dose (FDD) profiles, along with activity densities, and total activities needed to achieve specified does rates were studied as a function of photon energy and source-containment geometry. Dose-volume histograms (DVHs) were calculated to compare idealized balloon-applicator treatments to conventional 125I seed volume implants. Results: For achievable activity densities and total activities, classical low dose rate (LDR) treatments of residual disease at distances of up to 1 cm from the resection cavity wall are possible with balloon applicators having radii between 0.5 cm and 2.5 cm. The dose penetration of these applicators increases approximately linearly with balloon radius. The FDD profile can be made significantly more or less penetrating by combining selection of radionuclide with source-geometry manipulation. Comparisons with 125I seed-implant DVHs show that the applicator can provide a more conformal therapy with no target tissue underdosing, less target tissue overdosing, and no healthy tissue 'host spots;' however, more healthy tissue volume receives a dose of the prescribed dosage or less. Conclusions: This device, when filled with 125I solution, is suitable for classical LDR treatments and may be preferable to 125I interstitial-seed implants in several respects. Manipulation of the dosimetric properties of the device can improve its characteristics for brain tumor treatment and may make it suitable for boosting the lumpectomy margins in conservative breast cancer treatment.
KW - Brain neoplasm
KW - Dosimetry
KW - Glioma
KW - I
KW - Intracavitary brachytherapy
KW - Radioactive fluid
KW - Radiotherapy
UR - http://www.scopus.com/inward/record.url?scp=0032170647&partnerID=8YFLogxK
U2 - 10.1016/S0360-3016(98)00215-6
DO - 10.1016/S0360-3016(98)00215-6
M3 - Article
C2 - 9788425
AN - SCOPUS:0032170647
SN - 0360-3016
VL - 42
SP - 421
EP - 429
JO - International Journal of Radiation Oncology Biology Physics
JF - International Journal of Radiation Oncology Biology Physics
IS - 2
ER -