Document Detail


Adaptive planning using megavoltage fan-beam CT for radiation therapy with testicular shielding.
MedLine Citation:
PMID:  21925866     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
This study highlights the use of adaptive planning to accommodate testicular shielding in helical tomotherapy for malignancies of the proximal thigh. Two cases of young men with large soft tissue sarcomas of the proximal thigh are presented. After multidisciplinary evaluation, preoperative radiation therapy was recommended. Both patients were referred for sperm banking and lead shields were used to minimize testicular dose during radiation therapy. To minimize imaging artifacts, kilovoltage CT (kVCT) treatment planning was conducted without shielding. Generous hypothetical contours were generated on each "planning scan" to estimate the location of the lead shield and generate a directionally blocked helical tomotherapy plan. To ensure the accuracy of each plan, megavoltage fan-beam CT (MVCT) scans were obtained at the first treatment and adaptive planning was performed to account for lead shield placement. Two important regions of interest in these cases were femurs and femoral heads. During adaptive planning for the first patient, it was observed that the virtual lead shield contour on kVCT planning images was significantly larger than the actual lead shield used for treatment. However, for the second patient, it was noted that the size of the virtual lead shield contoured on the kVCT image was significantly smaller than the actual shield size. Thus, new adaptive plans based on MVCT images were generated and used for treatment. The planning target volume was underdosed up to 2% and had higher maximum doses without adaptive planning. In conclusion, the treatment of the upper thigh, particularly in young men, presents several clinical challenges, including preservation of gonadal function. In such circumstances, adaptive planning using MVCT can ensure accurate dose delivery even in the presence of high-density testicular shields.
Authors:
Poonam Yadav; Kevin Kozak; Ranjini Tolakanahalli; V Ramasubramanian; Bhudatt R Paliwal; James S Welsh; Yi Rong
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Publication Detail:
Type:  Case Reports; Journal Article     Date:  2011-09-16
Journal Detail:
Title:  Medical dosimetry : official journal of the American Association of Medical Dosimetrists     Volume:  37     ISSN:  1873-4022     ISO Abbreviation:  Med Dosim     Publication Date:  2012  
Date Detail:
Created Date:  2012-05-07     Completed Date:  2012-09-11     Revised Date:  2013-06-27    
Medline Journal Info:
Nlm Unique ID:  8908862     Medline TA:  Med Dosim     Country:  United States    
Other Details:
Languages:  eng     Pagination:  157-62     Citation Subset:  IM    
Copyright Information:
Published by Elsevier Inc.
Affiliation:
Department of Human Oncology, University of Wisconsin, Madison, Madison, WI, USA.
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MeSH Terms
Descriptor/Qualifier:
Humans
Lead
Male
Nerve Sheath Neoplasms / radiotherapy
Radiation Injuries / prevention & control*
Radiotherapy Planning, Computer-Assisted*
Sarcoma / radiotherapy
Testicular Diseases / prevention & control*
Thigh
Tomography, X-Ray Computed
Young Adult
Grant Support
ID/Acronym/Agency:
UL1 RR025011-04/RR/NCRR NIH HHS; UL1 RR025011-05/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
7439-92-1/Lead
Comments/Corrections

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