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Title: 'In Vivo' Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments

Abstract

In this prospective study, rectal dose was measured 'in vivo' using TLD-100 crystals (3x3x1 mm{sup 3}), and it has been compared to the prescribed dose. Measurements were performed in patients with cervical cancer classified in FIGO stages IB-IIIB and treated with high dose rate brachytherapy (HDR BT) at the Instituto Nacional de Cancerologia (INCan)

Authors:
; ;  [1]; ; ; ; ;  [2];  [3]
  1. Instituto de Fisica, UNAM, A.P. 20-364, Mexico 01000 D.F. (Mexico)
  2. Instituto Nacional de Cancerologia, Mexico 14000 D.F. (Mexico)
  3. Instituto de Ciencias Nucleares, UNAM, A.P. 70-543, Mexico 04510 D.F. (Mexico)
Publication Date:
OSTI Identifier:
21149256
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 1032; Journal Issue: 1; Conference: 10. Mexican symposium on medical physics, Mexico City (Mexico), 17-19 Mar 2008; Other Information: DOI: 10.1063/1.2979253; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
61 RADIATION PROTECTION AND DOSIMETRY; BIOLOGICAL RADIATION EFFECTS; BRACHYTHERAPY; CRYSTALS; DOSE RATES; DOSES; IN VIVO; NEOPLASMS; PATIENTS; RECTUM; THERMOLUMINESCENT DOSEMETERS; THERMOLUMINESCENT DOSIMETRY

Citation Formats

Gonzalez-Azcorra, S. A., Ruiz-Trejo, C., Buenfil, A. E., Mota-Garcia, A., Poitevin-Chacon, M. A., Santamaria-Torruco, B. J., Rodriguez-Ponce, M., Herrera-Martinez, F. P., and Gamboa de Buen, I. 'In Vivo' Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments. United States: N. p., 2008. Web. doi:10.1063/1.2979253.
Gonzalez-Azcorra, S. A., Ruiz-Trejo, C., Buenfil, A. E., Mota-Garcia, A., Poitevin-Chacon, M. A., Santamaria-Torruco, B. J., Rodriguez-Ponce, M., Herrera-Martinez, F. P., & Gamboa de Buen, I. 'In Vivo' Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments. United States. doi:10.1063/1.2979253.
Gonzalez-Azcorra, S. A., Ruiz-Trejo, C., Buenfil, A. E., Mota-Garcia, A., Poitevin-Chacon, M. A., Santamaria-Torruco, B. J., Rodriguez-Ponce, M., Herrera-Martinez, F. P., and Gamboa de Buen, I. Mon . "'In Vivo' Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments". United States. doi:10.1063/1.2979253.
@article{osti_21149256,
title = {'In Vivo' Dosimetry in High Dose Rate Brachytherapy for Cervical Cancer Treatments},
author = {Gonzalez-Azcorra, S. A. and Ruiz-Trejo, C. and Buenfil, A. E. and Mota-Garcia, A. and Poitevin-Chacon, M. A. and Santamaria-Torruco, B. J. and Rodriguez-Ponce, M. and Herrera-Martinez, F. P. and Gamboa de Buen, I.},
abstractNote = {In this prospective study, rectal dose was measured 'in vivo' using TLD-100 crystals (3x3x1 mm{sup 3}), and it has been compared to the prescribed dose. Measurements were performed in patients with cervical cancer classified in FIGO stages IB-IIIB and treated with high dose rate brachytherapy (HDR BT) at the Instituto Nacional de Cancerologia (INCan)},
doi = {10.1063/1.2979253},
journal = {AIP Conference Proceedings},
number = 1,
volume = 1032,
place = {United States},
year = {Mon Aug 11 00:00:00 EDT 2008},
month = {Mon Aug 11 00:00:00 EDT 2008}
}
  • The aim of this thesis project is to compare doses calculated from the treatment planning system using computed tomography images, with those measured 'in vivo' by using thermoluminescent dosimeters placed at different regions of the rectum and bladder of a patient during high-dose-rate intracavitary brachytherapy treatment of uterine cervical carcinoma. The experimental dosimeters characterisation and calibration have concluded and the protocol to carry out the 'in vivo' measurements has been established. In this work, the calibration curves of two types of thermoluminescent dosimeters (rods and chips) are presented, and the proposed protocol to measure the 'in vivo' dose is fullymore » described.« less
  • Purpose: To evaluate the predictive factors for rectal dose of the first fraction of high-dose-rate intracavitary brachytherapy (HDR-ICBT) in patients with cervical cancer. Methods and Materials: From March 1993 through February 2008, 946 patients undergoing pelvic irradiation and HDR-ICBT were analyzed. Examination under anesthesia (EUA) at the first implantation of the applicator was usually performed in the early period. Rectal point was determined radiographically according to the 38th Report of the International Commission of Radiation Units and Measurements (ICRU). The ICRU rectal dose (PRD) as a percentage of point A dose was calculated; multiple linear regression models were used tomore » predict PRD. Results: Factors influencing successful rectal dose calculation were EUA (p < 0.001) and absence of diabetes (p = 0.047). Age (p < 0.001), body weight (p = 0.002), diabetes (p = 0.020), and EUA (p < 0.001) were independent factors for the PRD. The predictive equation derived from the regression model was PRD (%) = 57.002 + 0.443 x age (years) - 0.257 x body weight (kg) + 6.028 x diabetes (no: 0; yes: 1) - 8.325 x EUA (no: 0; yes: 1) Conclusion: Rectal dose at the first fraction of HDR-ICBT is positively influenced by age and diabetes, and negatively correlated with EUA and body weight. A small fraction size at point A may be considered in patients with a potentially high rectal dose to reduce the biologically effective dose if the ICRU rectal dose has not been immediately obtained in the first fraction of HDR-ICBT.« 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 evaluate the improvement in plan quality when various combinations of 192Ir, 60Co, and 169Yb sources are used in combination with a novel direction modulated brachytherapy (DMBT) tandem applicator for high dose rate brachytherapy of cervical cancer. Methods: The proposed DMBT tandem applicator is designed for image-guided adaptive brachytherapy (IGABT), especially MRI, of cervical cancer. It has 6 peripheral holes of 1.3-mm width, grooved along a 5.4-mm diameter nonmagnetic tungsten alloy rod of density 18.0 g/cc, capable of generating directional dose profiles - leading to enhanced dose sculpting capacity through inverse planning. Monte Carlo simulations of the three HDRmore » sources individually inside the DMBT applicator were performed and imported into an in-house developed inverse optimization code. We then performed inverse planning with 14 cervical cancer patients enrolled in EMBRACE study. In all patients, 3D MRI-based planning was performed while utilizing 1) tandem-ring and needles attached-to-ring (7 patients) and 2) tandem-ring and needles both attached-to-ring and free-hand-loaded (7 patients), in accordance with the GEC-ESTRO recommendations. All plans were normalized to receive the same HRCTV D90 and DVH parameters were evaluated. Results: The DMBT tandem was used in all cases. Overall, the combined use of two sources (192Ir-60Co and 192Ir-169Yb, but not 60Co-169Yb) generally produced better quality plans than with the 192Ir source alone in terms of sparing OARs. For example, up to 3.5, 4.4, and 3.9% individual reductions in D2cc were observed for the bladder, rectum, and sigmoid, respectively, between 192Ir-60Co and 192Ir-only plans for patient cases in #1. While up to 5.5, 2.0, and 5.7% individual reductions were observed for patient cases in #2. Conclusion: We have demonstrated that, in addition to “directional modulation” of DMBT, use of multiple sources with sufficient differences in energy can be utilized to achieve additional improvement in plan quality for IGABT of cervical cancer.« less
  • Purpose: To determine the efficacy and toxicity of extended-field radiotherapy (RT) with concurrent platinum-based chemotherapy in patients with uterine cervical carcinoma and positive para-aortic nodes. Methods and Materials: We retrospectively reviewed the results for 33 women with Stage IB-IVB cervical cancer. Each patient had received 59.4 Gy, including a three-dimensional conformal boost to the para-aortic lymph nodes and 41.4-50.4 Gy of external beam radiotherapy to the pelvis. Each patient also underwent six or seven applications of high-dose-rate brachytherapy (median, 5 Gy to point A at each session). Results: The median follow-up period of surviving patients was 39 months. The mostmore » common acute toxicity was hematologic, observed in 23 women. Severe acute and late gastrointestinal toxicity was observed in 3 and 4 patients, respectively. More than three-quarters of patients showed a complete response, encompassing the primary mass, metastatic pelvic, and para-aortic lymph nodes. Of the 33 women, 15 had no evidence of disease, 6 had persistent disease, 4 developed in-field failures, and 6 developed distant failures. The 5-year overall and disease-free survival rate was 47% and 42%, respectively. Conclusion: Concurrent chemoradiotherapy with extended-field radiotherapy is feasible in women with uterine cervical carcinoma and positive para-aortic lymph nodes, with acceptable late morbidity and a high survival rate, although it was accompanied by substantial acute toxicity.« less