Faculty Collaboration Database

Interfractional variations in patient setup and anatomic change assessed by daily computed tomography. Int J Radiat Oncol Biol Phys 2007 Jun 01;68(2):581-91

Date

03/03/2007

Pubmed ID

17331669

DOI

10.1016/j.ijrobp.2006.12.024

Scopus ID

2-s2.0-34247893798 (requires institutional sign-in at Scopus site)   108 Citations

Abstract

PURPOSE: To analyze the interfractional variations in patient setup and anatomic changes at seven anatomic sites observed in image-guided radiotherapy.

METHODS AND MATERIALS: A total of 152 patients treated at seven anatomic sites using a Hi-Art helical tomotherapy system were analyzed. Daily tomotherapy megavoltage computed tomography images acquired before each treatment were fused to the planning kilovoltage computed tomography images to determine the daily setup errors and organ motions and deformations. The setup errors were corrected before treatment and were used, along with the organ motions, to determine the clinical target volume/planning target volume margins. The organ motions and deformations for 3 representative patient cases (pancreas, uterus, and soft-tissue sarcoma) and for 14 kidneys of 7 patients are presented.

RESULTS: Interfractional setup errors in the skull, brain, and head and neck are significantly smaller than those in the chest, abdomen, pelvis, and extremities. These site-specific relationships are statistically significant. The margins required to account for these setup errors range from 3 to 8 mm for the seven sites. The margin to account for both setup errors and organ motions for kidney is 16 mm. Substantial interfractional anatomic changes were observed. For example, the pancreas moved up to +/-20 mm and volumes of the uterus and sarcoma varied <or=30% and 100%, respectively.

CONCLUSION: The interfractional variations in patient setup and in shapes, sizes, and positions of both targets and normal structures are site specific and may be used to determine the site-specific margins. The data presented in this work dealing with seven anatomic sites may be useful in developing adaptive radiotherapy.

Author List

Li XA, Qi XS, Pitterle M, Kalakota K, Mueller K, Erickson BA, Wang D, Schultz CJ, Firat SY, Wilson JF

Authors

Beth A. Erickson MD Professor in the Radiation Oncology department at Medical College of Wisconsin
Selim Firat MD Professor in the Radiation Oncology department at Medical College of Wisconsin
Christopher J. Schultz MD Chair, Professor in the Radiation Oncology department at Medical College of Wisconsin

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

Brain Neoplasms
Extremities
Female
Head and Neck Neoplasms
Humans
Male
Movement
Neoplasms
Pancreatic Neoplasms
Pelvic Neoplasms
Radiotherapy, Intensity-Modulated
Scalp
Skin Neoplasms
Stomach Neoplasms
Thoracic Neoplasms
Tomography, Spiral Computed
Uterine Neoplasms