Comparison of traditional low-dose-rate to optimized and nonoptimized high-dose-rate tandem and ovoid dosimetry

被引:11
作者
Decker, WE [1 ]
Erickson, B [1 ]
Albano, K [1 ]
Gillin, M [1 ]
机构
[1] Med Coll Wisconsin, Dept Radiat Oncol, Milwaukee, WI 53226 USA
来源
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS | 2001年 / 50卷 / 02期
关键词
cervix cancer; brachytherapy; dosimetry; HDR;
D O I
10.1016/S0360-3016(01)01542-5
中图分类号
R73 [肿瘤学];
学科分类号
100214 ;
摘要
Purpose: Few dose specification guidelines exist when attempting to perform high-dose-rate (HDR) dosimetry. The purpose of this study was to model low-dose-rate (LDR) dosimetry, using parameters common in HDR dosimetry, to achieve the "pear-shape" dose distribution achieved with LDR tandem and ovoid applications. Methods and Materials: Radiographs of Fletcher-Suit LDR applicators and Nucletron "Fletcher-like" HDR applicators mere taken with the applicators in an idealized geometry. Traditional Fletcher loadings of 3M Cs-137 sources and the Theratronics Planning System were used for LDR dosimetry. HDR dosimetry was performed using the Nucletron Microselectron HDR UPS V11.22 with an Ir-192 source. Dose optimization points were initially located along a line 2 cm lateral to the tandem, beginning at the tandem tip at 0.5-cm intervals, ending at the sail, and optimized to 100% of the point A dose. A single dose optimization point was also placed laterally from the center of each ovoid equal to the radius of the ovoid (ovoid surface dose). For purposes of comparison, dose was also calculated for points A and B, and a point located 1 cm superior to the tandem tip in the plane of the tandem, (point F). Four- and 6-cm tandem lengths and 2.0-, 2.5-, and 3.0-cm ovoid diameters were used for this study. Based on initial findings, dose optimization schemes were developed to best approximate LDR dosimetry. Finally, radiographs were obtained of HDR applications in two patients. These radiographs were used to compare the optimization schemes with "nonoptimized" treatment plans. Results: Calculated doses for points A and B were similar for LDR, optimized HDR, and nonoptimized HDR. The optimization scheme that used tapered dose points at the tandem tip and optimized a single ovoid surface point on each ovoid to 170% of point A resulted in a good approximation of LDR dosimetry. Nonoptimized HDR resulted in higher doses at point F, the bladder, and at points lateral to the tandem tip than both the optimized plan or the LDR plan. Conclusion: Optimized HDR allows specification of dose to points of interest, can approximate LDR dosimetry, and appears superior to nonoptimized HDR treatment planning, at least at the tandem tip. An optimization scheme is presented that approximates LDR dosimetry. (C) 2001 Elsevier Science Inc.
引用
收藏
页码:561 / 567
页数:7
相关论文
共 13 条
[1]   Carcinoma of the intact uterine cervix treated with radiotherapy alone: A French cooperative study: Update and multivariate analysis of prognostics factors [J].
Barillot, I ;
Horiot, JC ;
Pigneux, J ;
Schraub, S ;
Pourquier, H ;
Daly, N ;
Bolla, M ;
Rozan, R .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1997, 38 (05) :969-978
[2]  
ELBARADIE MM, 1998, J BRACHYTHER INT, V14, P97
[3]  
ERICKSON B, 1997, J BRACHYTHER INT, V13, P179
[4]   OPTIMIZATION OF HIGH DOSE-RATE CERVIX BRACHYTHERAPY .1. DOSE DISTRIBUTION [J].
HOUDEK, PV ;
SCHWADE, JG ;
ABITBOL, AA ;
PISCIOTTA, V ;
WU, XD ;
SERAGO, CF ;
MARKOE, AM ;
LEWIN, AA ;
AVERETTE, HE ;
SEVIN, BU ;
BRANDON, AH ;
FIEDLER, JA ;
COHEN, AM ;
FAYAD, F .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1991, 21 (06) :1621-1625
[5]  
*ICRU, 1985, 38 ICRU, V38, P1
[6]   GEOMETRY ADOPTED BY MANCHESTER RADIUM APPLICATORS AND SELECTRON AFTERLOADING APPLICATORS IN INTRACAVITARY TREATMENT FOR CARCINOMA CERVIX UTERI [J].
JONES, DA ;
NOTLEY, HM ;
HUNTER, RD .
BRITISH JOURNAL OF RADIOLOGY, 1987, 60 (713) :481-485
[7]   Over 20 years of progress in radiation oncology: Cervical cancer [J].
Lanciano, R ;
Thomas, G ;
Eifel, PJ .
SEMINARS IN RADIATION ONCOLOGY, 1997, 7 (02) :121-126
[8]   IMPACT OF OPTIMIZED TREATMENT PLANNING FOR TANDEM AND RING, AND TANDEM AND OVOIDS, USING HIGH-DOSE-RATE BRACHYTHERAPY FOR CERVICAL-CANCER [J].
NOYES, WR ;
PETERS, NE ;
THOMADSEN, BR ;
FOWLER, JF ;
BUCHLER, DA ;
STITT, JA ;
KINSELLA, TJ .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1995, 31 (01) :79-86
[9]   Tumor size, irradiation dose, and long-term outcome of carcinoma of uterine cervix [J].
Perez, CA ;
Grigsby, PW ;
Chao, KSC ;
Mutch, DG ;
Lockett, MA .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1998, 41 (02) :307-317
[10]   Literature analysis of high dose rate brachytherapy fractionation schedules in the treatment of cervical cancer: Is there an optimal fractionation schedule? [J].
Petereit, DG ;
Pearcey, R .
INTERNATIONAL JOURNAL OF RADIATION ONCOLOGY BIOLOGY PHYSICS, 1999, 43 (02) :359-366