skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: In vivo isocenter dose in two hip prosthesis patients

Abstract

Hip prostheses may cause irradiation dose inhomogeneities in conventional four-field target volumes to the pelvis. Two patients, with bilateral and unilateral prostheses, were subjected to thermoluminescent dosimetry measurements in the prostatic urethra during 24 MV photon portal exposures. The results suggested a 13% decrease in absorbed dose only for conventional four-field beam geometry with bilateral prostheses, as compared to oblique four-field beam geometry or unilateral prosthesis. This supports the suggestion that beam technique modifications may be warranted for patients with hip prostheses.

Authors:
; ; ; ;  [1]
  1. (Department of Radiology, University of Colorado, Denver (USA))
Publication Date:
OSTI Identifier:
5397026
Resource Type:
Journal Article
Resource Relation:
Journal Name: International Journal of Radiation Oncology, Biology and Physics; (United States); Journal Volume: 20:6; Journal Issue: 6
Country of Publication:
United States
Language:
English
Subject:
62 RADIOLOGY AND NUCLEAR MEDICINE; NEOPLASMS; RADIOTHERAPY; PELVIS; PROSTHESES; RADIATION DOSES; DATA COVARIANCES; ALLOYS; PATIENTS; THERMOLUMINESCENT DOSIMETRY; BODY; BODY AREAS; DISEASES; DOSES; DOSIMETRY; MEDICAL SUPPLIES; MEDICINE; NUCLEAR MEDICINE; RADIOLOGY; THERAPY; 550603* - Medicine- External Radiation in Therapy- (1980-)

Citation Formats

Burleson, W.D., Stutzman, C.D., Stitt, J.A., Karlsson, U.L., and Mian, T.A. In vivo isocenter dose in two hip prosthesis patients. United States: N. p., 1991. Web. doi:10.1016/0360-3016(91)90248-3.
Burleson, W.D., Stutzman, C.D., Stitt, J.A., Karlsson, U.L., & Mian, T.A. In vivo isocenter dose in two hip prosthesis patients. United States. doi:10.1016/0360-3016(91)90248-3.
Burleson, W.D., Stutzman, C.D., Stitt, J.A., Karlsson, U.L., and Mian, T.A. 1991. "In vivo isocenter dose in two hip prosthesis patients". United States. doi:10.1016/0360-3016(91)90248-3.
@article{osti_5397026,
title = {In vivo isocenter dose in two hip prosthesis patients},
author = {Burleson, W.D. and Stutzman, C.D. and Stitt, J.A. and Karlsson, U.L. and Mian, T.A.},
abstractNote = {Hip prostheses may cause irradiation dose inhomogeneities in conventional four-field target volumes to the pelvis. Two patients, with bilateral and unilateral prostheses, were subjected to thermoluminescent dosimetry measurements in the prostatic urethra during 24 MV photon portal exposures. The results suggested a 13% decrease in absorbed dose only for conventional four-field beam geometry with bilateral prostheses, as compared to oblique four-field beam geometry or unilateral prosthesis. This supports the suggestion that beam technique modifications may be warranted for patients with hip prostheses.},
doi = {10.1016/0360-3016(91)90248-3},
journal = {International Journal of Radiation Oncology, Biology and Physics; (United States)},
number = 6,
volume = 20:6,
place = {United States},
year = 1991,
month = 6
}
  • Purpose: Metal artifact reduction (MAR) software in computed tomography (CT) was previously evaluated with phantoms demonstrating the algorithm is capable of reducing metal artifacts without affecting the overall image quality. The goal of this study is to determine the dosimetric impact when calculating with CT datasets reconstructed with and without MAR software. Methods: Twelve head and neck cancer patients with dental fillings and four pelvic cancer patients with hip prosthesis were scanned with a GE Optima RT 580 CT scanner. Images were reconstructed with and without the MAR software. 6MV IMRT and VMAT plans were calculated with AAA on themore » MAR dataset until all constraints met our clinic’s guidelines. Contours from the MAR dataset were copied to the non-MAR dataset. Next, dose calculation on the non-MAR dataset was performed using the same field arrangements and fluence as the MAR plan. Conformality index, D99% and V100% to PTV were compared between MAR and non-MAR plans. Results: Differences between MAR and non-MAR plans were evaluated. For head and neck plans, the largest variations in conformality index, D99% and V100% were −3.8%, −0.9% and −2.1% respectively whereas for pelvic plans, the biggest discrepancies were −32.7%, −0.4% and -33.5% respectively. The dosimetric impact from hip prosthesis is greater because it produces more artifacts compared to dental fillings. Coverage to PTV can increase or decrease depending on the artifacts since dark streaks reduce the HU whereas bright streaks increase the HU. In the majority of the cases, PTV dose in the non-MAR plans is higher than MAR plans. Conclusion: With the presence of metals, MAR algorithm can allow more accurate delineation of targets and OARs. Dose difference between MAR and non-MAR plans depends on the proximity of the organ to the high density material, the streaking artifacts and the beam arrangements of the plan.« less
  • To investigate the doses received by the hippocampus and normal brain tissue during a course of stereotactic radiation therapy using a single isocenter (SI)–based or multiple isocenter (MI)–based treatment planning in patients with less than 4 brain metastases. In total, 10 patients with magnetic resonance imaging (MRI) demonstrating 2-3 brain metastases were included in this retrospective study, and 2 sets of stereotactic intensity-modulated radiation therapy (IMRT) treatment plans (SI vs MI) were generated. The hippocampus was contoured on SPGR sequences, and doses received by the hippocampus and the brain were calculated and compared between the 2 treatment techniques. A totalmore » of 23 lesions in 10 patients were evaluated. The median tumor volume, the right hippocampus volume, and the left hippocampus volume were 3.15, 3.24, and 2.63 mL, respectively. In comparing the 2 treatment plans, there was no difference in the planning target volume (PTV) coverage except in the tail for the dose-volume histogram (DVH) curve. The only statistically significant dosimetric parameter was the V{sub 100}. All of the other measured dosimetric parameters including the V{sub 95}, V{sub 99}, and D{sub 100} were not significantly different between the 2 treatment planning techniques. None of the dosimetric parameters evaluated for the hippocampus revealed any statistically significant difference between the MI and SI plans. The total brain doses were slightly higher in the SI plans, especially in the lower dose region, although this difference was not statistically different. The use of SI-based treatment plan resulted in a 35% reduction in beam-on time. The use of SI treatments for patients with up to 3 brain metastases produces similar PTV coverage and similar normal tissue doses to the hippocampus and the brain when compared with MI plans. SI treatment planning should be considered in patients with multiple brain metastases undergoing stereotactic treatment.« less
  • Purpose: The largest in vivo dosimetry study for interstitial brachytherapy yet examined was performed using new radiophotoluminescence glass dosimeters (RPLGDs). Based on the results, a dose prescription technique achieving high reproducibility and eliminating large hyperdose sleeves was studied. Methods and materials: For 61 head-and-neck cancer patients who underwent high-dose-rate interstitial brachytherapy, new RPLGDs were used for an in vivo study. The Paris System was used for implant. An arbitrary isodose surface was selected for dose prescription. Locations of 83 dosimeters were categorized as on target (n = 52) or on nontarget organ (n = 31) and were also scaled accordingmore » to % basal dose isodose surface (% BDIS). Compatibility (measured dose/calculated dose) was analyzed according to location. The hyperdose sleeve was assessed in terms of prescription surface expressed in % BDIS. Results: The spread of compatibilities was larger for on nontarget organ (1.06 {+-} 0.32) than for on target (0.87 {+-} 0.17, p = 0.01). Within on target RPLGDs, compatibility on < 95% BDIS (0.95 {+-} 0.10) was better than on {>=}95% BDIS (0.84 {+-} 0.18, p = 0.02). The number of patients with diameter of hyperdose sleeve {>=}10 mm was increased with a dose prescription to < 77% BDIS (p = 0.046). For nontarget organs, the maximal positive deviation was 84% of the calculated dose. Conclusions: Dose prescription is recommended to >77% and < 95% BDIS for reproducibility and elimination of excessive hyperdose sleeve. For organs at risk, radioprotection should be considered even when calculated dose seems sufficiently low. Further development of planning software is necessary to prevent overestimation.« less
  • Purpose: To perform the largest in vivo dosimetry study for interstitial brachytherapy yet to be undertaken using a new radiophotoluminescence glass dosimeter (RPLGD) in patients with pelvic malignancy and to study the limits of contemporary planning software based on the results. Patients and Methods: Sixty-six patients with pelvic malignancy were treated with high-dose-rate interstitial brachytherapy, including prostate (n = 26), gynecological (n = 35), and miscellaneous (n = 5). Doses for a total of 1004 points were measured by RPLGDs and calculated with planning software in the following locations: rectum (n = 549), urethra (n = 415), vagina (n =more » 25), and perineum (n = 15). Compatibility (measured dose/calculated dose) was analyzed according to dosimeter location. Results: The compatibility for all dosimeters was 0.98 {+-} 0.23, stratified by location: rectum, 0.99 {+-} 0.20; urethra, 0.96 {+-} 0.26; vagina, 0.91 {+-} 0.08; and perineum, 1.25 {+-} 0.32. Conclusions: Deviations between measured and calculated doses for the rectum and urethra were greater than 20%, which is attributable to the independent movements of these organs and the applicators. Missing corrections for inhomogeneity are responsible for the 9% negative shift near the vaginal cylinder (specific gravity = 1.24), whereas neglect of transit dose contributes to the 25% positive shift in the perineal dose. Dose deviation of >20% for nontarget organs should be taken into account in the planning process. Further development of planning software and a real-time dosimetry system are necessary to use the current findings and to achieve adaptive dose delivery.« less