Purpose: Currently, CT has been widely used for HDR planning as MRI is not widely available for tumor imaging. Conventional pear-shaped isodose distribution may not be discarded completely because of possible microscopic diseases into parametrium/uterus. For patients with small uterus, organs at risk (OARs) can fall inside 100% conventional pear-shaped isodose-line. This study compares two pear-shaped based dose optimization methods for OARs sparing.
Methods: Seven cervical cancer patients with small uterus were evaluated using 2 methods. For Method A, with conventional dwell-time loading, point A lateral distance was reduced until all OARs' D2cc were within the dose limits. For Method B, a reference target volume was generated using conventional pear-shaped 100% isodose- surface. While isodose-line near the point A was adjusted for OARs sparing, isodose-line surrounding ovoids were optimized to match the reference target volume. For equivalent OAR sparing, 100% isodose-line width (lateral dimension) at 1 cm inferior to point A (-1 cm) and at across centers of ovoids (ovoid) were compared between the 2 methods.
Results: OARs fall inside conventional 100% isodose-line in all cases. Median position of hot spots was 0.2 cm (range -;1.2 to 2.9 cm) superior to point A. Using Method A, point A lateral distance was adjusted to 1.4-1.7 cm for OARs sparing. Median width of 100% isodose-line was 5.82 cm at ovoid level, and 4.50 cm at -1 cm level. At ovoid level, median width of 100% isodose-line was reduced by 9(8-13)% for Method A, and was unchanged for Method B. At -1 cm level, median width of 100% isodose-line was reduced by 19(2- 33)% for Method A, and 11(0-15)% for Method B.
Conclusions: for patients with small uterus, OARs are often fall inside 100% pear-s haped isodose-line near point A level. OARs can be spared without dramatically compromise treatment volume coverage around cervix using Method B.
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http://dx.doi.org/10.1118/1.4735522 | DOI Listing |
Pract Radiat Oncol
January 2025
Department of Radiation Oncology, University of Pittsburgh Medical Center Hillman Cancer Center, Williamsport, Pennsylvania.
World J Clin Cases
June 2024
Neurosurgery Unit, Head-Neck and NeuroScience Department, University Hospital of Udine, Udine 33100, Italy.
Background: Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach.
Aim: To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG).
Neurosurgery
August 2024
Department of Neurosurgery, Stanford University School of Medicine, Stanford , California , USA.
Background And Objectives: Ependymoma is commonly classified as World Health Organization grade 2 with the anaplastic variant categorized as grade 3. Incomplete resection or anaplastic features can result in unfavorable outcomes. Stereotactic radiosurgery (SRS) provides a minimally invasive approach for recurrent ependymomas.
View Article and Find Full Text PDFBiomed Phys Eng Express
May 2024
South Carolina Oncology Associates, Columbia, SC 29210, United States of America.
The aim of this study is to determine the planar dose distribution of irregularly-shaped electron beams at their maximum dose depth () using the modied lateral build-up ratio (LBR) and curve-fitting methods.Circular and irregular cutouts were created using Cerrobend alloy for a 14 × 14 cmapplicator. Percentage depth dose (PDD) at the standard source-surface-distance (SSD = 100 cm) and point dose at different SSD were measured for each cutout.
View Article and Find Full Text PDFBackground Stereotactic radiosurgery is a well-established treatment option for the management of various benign and malignant brain tumors. It can be delivered with several treatment platforms, usually requiring shielded radiation vaults to meet regulatory safety requirements. Recent technical advances have led to the first self-shielding platform enabling the delivery of gyroscopic radiosurgery (GRS).
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