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CT-guided interstitial implantation of gynecologic malignancies. Int J Radiat Oncol Biol Phys 1996 Oct 01;36(3):699-709

Date

10/01/1996

Pubmed ID

8948356

DOI

10.1016/s0360-3016(96)00373-2

Scopus ID

2-s2.0-0030271772   65 Citations

Abstract

PURPOSE: To establish the efficacy of computed tomography (CT)-based planning and analysis of transperineal implants.

METHODS AND MATERIALS: For patients with bulky disease or geometrically unfavorable anatomy, transperineal interstitial implantation of gynecologic tumors offers an alternative to standard intracavitary techniques. Control of dose rate and total dose distributions to produce a homogenous, low dose rate implant presents a challenge to the radiation oncologist in these complex implants, as does the relationship of these distributions to the patients's anatomy. We have used CT imaging following needle implantation, prior to source loading, in 25 patients (28 implants), as an aid in both the planning of the implant and the analysis of the dosimetry.

RESULTS: The spatial relationship between the needles and the normal anatomy can be clearly defined, despite the presence of some artifacts. Tumor volume is less clearly visualized but the adequacy of needle placement can be assessed and adjusted if necessary. Modifications of the planned source placement, based upon the location of specific needles and critical structures, can be made prior to loading the patient. Dose rate and total dose distributions are displayed with the appropriate anatomy on axial images and on reconstructed sagittal and coronal planes. Multiple points of dose specification for the rectum and the bladder are easily defined. Dose rate adjustment can be made by selectively changing the activity associated with a particular needle or needles. Multiple implants as well as external beam irradiation can also be integrated.

CONCLUSIONS: CT-based dosimetry has permitted intelligent planning decisions to be made prior to and during these implants. It has further allowed more accurate anatomically based dosimetric analysis, with visualization and control of dose rate and total dose distributions displayed together with the patient's anatomy. This more elaborate analysis should ultimately lead to a better understanding of the reasons for local control and complications and their relationships to dose rate, total dose, and volume.

Author List

Erickson B, Albano K, Gillin M

Authors

Katherine Albano Medical Physicist Sr in the Radiation Oncology department at Medical College of Wisconsin
Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of Wisconsin




MESH terms used to index this publication - Major topics in bold

Brachytherapy
Female
Genital Neoplasms, Female
Humans
Radiography, Interventional
Radiotherapy Dosage
Radiotherapy Planning, Computer-Assisted
Tomography, X-Ray Computed
jenkins-FCD Prod-482 91ad8a360b6da540234915ea01ff80e38bfdb40a