Fractionated high-dose-rate brachytherapy in primary carcinoma of the nasopharynx.

1998 ◽  
Vol 16 (6) ◽  
pp. 2213-2220 ◽  
Author(s):  
P C Levendag ◽  
P I Schmitz ◽  
P P Jansen ◽  
W M Eijkenboom ◽  
A G Visser ◽  
...  
Keyword(s):  
Dose Rate ◽  
Treatment Time ◽  
Univariate Analysis ◽  
High Dose Rate ◽  
Local Failure ◽  
Dose Effect ◽  
High Dose ◽  
Outpatient Basis ◽  
Overall Treatment Time ◽  
Prognostic Group

PURPOSE A growing body of data suggests that local control in nasopharyngeal cancer (NPC) is related to the radiation dose administered. We conducted a single-institution study of high-dose radiotherapy (RT), which incorporated high-dose-rate (HDR) brachytherapy (BT). These results were analyzed together with data obtained from controls who did not receive BT. PATIENTS AND METHODS The BT group comprised 42 consecutive patients of whom 29 patients were staged according to the tumor, node, metastasis system as T1 through 3, 13 patients were T4, and 34 patients were N+ disease. BT was administered on an outpatient basis by means of a specially designed flexible nasopharyngeal applicator, and the dose distributions were optimized. Treatment for T1 through 3 tumors comprised 60 Gy of external-beam radiotherapy (ERT) followed by six fractions of 3 Gy BT (two fractions per day). Patients with parapharyngeal tumor extension and/or T4 tumors received 70 Gy ERT and four fractions of 3 Gy BT. The no-BT group consisted of all patients treated from 1965 to 1991 (n = 109), of whom 82 patients had stages T1 through 3, 27 patients had T4, and 80 patients had N+ disease. Multivariate Cox proportional hazards analyses were performed by using the end points time to local failure (TTLF), time to distant failure (TTDF), disease-free survival (DFS), cause-specific survival (CSS), and the prognostic factors age, tumor stage, node stage, and grade. Because the overall treatment time varied substantially in the no-BT group, the dependence of local failure (LF) on the physical dose as well as the biologic effective dose (BED) corrected for the overall treatment time (OTT) (BEDcor10) was studied. RESULTS The BT group had a superior 3-year local relapse-free rate (86% v 60%; univariate analysis, P = .004). Multivariate analysis showed hazards ratios for BT versus no-BT of 0.24 for TTLF (P = .003), 0.35 for TTDF (P = .038), 0.31 for DFS (P < .001), and 0.44 for CSS (P = .01). The best prognostic group consisted of patients with T1 through 3, N0 through 2b tumors treated with BT who attained a 5-year TTLF of 94% and CSS of 91%. In contrast, the worst prognostic group, i.e., 5-year TTLF of 47% and CSS of 24%, was composed of patients with T4 and/or N2c through 3 tumors who did not receive BT. CONCLUSION High doses of radiation (73 to 95 Gy) can be administered to patients with NPC with minimal morbidity by means of optimized HDR-BT. The use of a BT boost proved to be of significant benefit, particularly in patients with T1 through 3, N0 through 2b disease. The steep dose-effect relationship seen for the physical dose and the BEDcor10 indicates that the results are dose related. The analysis has identified a poor prognostic group in whom treatment intensification with chemotherapy (CHT) is indicated.

High dose rate brachytherapy with surface applicators: Treatment for nonmelanomatous skin cancer

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 15543-15543 ◽  
Author(s):  
J. Musmacher ◽  
M. Ghaly ◽  
K. Satchwill
Keyword(s):  
Dose Rate ◽  
Dose Distribution ◽  
Treatment Time ◽  
High Dose Rate ◽  
High Dose ◽  
Outpatient Basis ◽  
Hdr Brachytherapy ◽  
X Rays ◽  
High Dose Rate Brachytherapy ◽  
Lateral Canthus

15543 Background: To assess the use of HDR surface applicators as an alternative radiotherapy modality to external radiation (electrons or low-energy x-rays) for the treatment of skin lesions of the head and neck. Skin carcinomas require efficient and accurate delivery of HDR Brachytherapy, which can be precisely reproduced on an outpatient basis. Methods: Patients were treated to various sites, which included lesions of the face and scalp. Thermoplastic casts were fitted with Leipzig Surface Applicators and custom molded to the patient to treat squamous or basal cell carcinomas ≤ 2 cm in diameter. A custom surface mold applicator (Freiburg Flap) was used for lesions up to 4 cm. Planning target volume included the tumor plus a 5 mm margin. Biweekly photographs of the treatment volume were taken for documentation and monitoring of radiation reactions. Treatment was delivered by HDR Brachytherapy (Ir-192), 5 Gy per fraction, twice per week for four weeks to a 5 mm depth. TLD’s were placed at the center of the treated volume under the applicator and at critical structures (i.e. lateral canthus of the ipsilateral eye, auditory canal or gingivolabial sulcus) twice during the course of treatment. Results: Patients’ setup and reproducibility were accurate and treatment time was short which added great convenience for the patients. With the HDR surface applicators, dose distribution was uniform in the surface of the skin and at 5 mm depth in the whole area of the applicator. Differences between the areas of maximum and minimum dose at this depth did not reach values higher than 5% of the prescribed dose. At the edges of the applicators, the dose gradient was sharp, with the detected dose at 5 mm from the applicator being negligible. An exudative radiation reaction was noted in some patients, which reversed with appropriate therapy. Conclusion: High Dose Rate Brachytherapy offers a highly effective treatment of skin carcinomas. Surface applicators, used in conjunction with HDR brachytherapy equipment, make a uniform dose distribution and sharp dose gradient at the edge of the treatment field. Surface applicators are easy and safe to use, and they fit very accurately for each fraction. These applicators have the ability to become the standard treatment for skin carcinomas in the near future. No significant financial relationships to disclose.

Overall Interval Brachytherapy Treatment Time In High Dose Rate Brachytherapy (HDRBT) For Endometrial Carcinoma (EC)

2011 ◽  
Vol 81 (2) ◽  
pp. S477 ◽  
Author(s):  
A. Rovirosa ◽  
C. Ascaso ◽  
I. Valduvieco ◽  
B. Carlos ◽  
A. Herreros ◽  
...  
Keyword(s):  
Endometrial Carcinoma ◽  
Dose Rate ◽  
Treatment Time ◽  
High Dose Rate ◽  
High Dose ◽  
High Dose Rate Brachytherapy

scholarly journals The Dosimetric and Temporal Effects of Respiratory-Gated, High-Dose-Rate Radiation Therapy in Patients With Lung Cancer

2018 ◽  
Vol 18 ◽  
pp. 153303381881607 ◽  
Author(s):  
Ouided Rouabhi ◽  
Brandie Gross ◽  
John Bayouth ◽  
Junyi Xia
Keyword(s):  
Lung Cancer ◽  
Radiation Therapy ◽  
Dose Rate ◽  
Treatment Time ◽  
High Dose Rate ◽  
High Dose ◽  
Lung Dose ◽  
Treatment Delivery ◽  
Treatment Plans ◽  
Mean Lung Dose

Purpose: To evaluate the dosimetric and temporal effects of high-dose-rate respiratory-gated radiation therapy in patients with lung cancer. Methods: Treatment plans from 5 patients with lung cancer (3 nongated and 2 gated at 80EX-80IN) were retrospectively evaluated. Prescription dose for these patients varied from 8 to 18 Gy/fraction with 3 to 5 treatment fractions. Using the same treatment planning criteria, 4 new treatment plans, corresponding to 4 gating windows (20EX-20IN, 40EX-40IN, 60EX-60IN, and 80EX-80IN), were generated for each patient. Mean tumor dose, mean lung dose, and lung V20 were used to assess the dosimetric effects. A MATLAB algorithm was developed to compute treatment time. Results: Mean lung dose and lung V20 were on average reduced between −16.1% to −6.0% and −20.0% to −7.2%, respectively, for gated plans when compared to the corresponding nongated plans, and between −5.8% to −4.2% and −7.0% to −5.4%, respectively, for plans with smaller gating windows when compared to the corresponding plans gated at 80EX-80IN. Treatment delivery times of gated plans using high-dose rate were reduced on average between −19.7% (−0.10 min/100 MU) and −27.2% (−0.13 min/100 MU) for original nongated plans and −15.6% (−0.15 min/100 MU) and −20.3% (−0.19 min/100 MU) for original 80EX-80IN-gated plans. Conclusion: Respiratory-gated radiation therapy in patients with lung cancer can reduce lung dose while maintaining tumor dose. Because treatment delivery during gated therapy is discontinuous, total treatment time may be prolonged. However, this increase in treatment time can be offset by increasing the dose delivery rate. Estimation of treatment time may be helpful in selecting patients for respiratory gating and choosing appropriate gating windows.

The Variability of Applicator Position among High Dose Rate Intracavitary Brachytherapy Applications in Cervical Cancer Patients Treated with Ring & Tandem Applicators

2007 ◽  
Vol 93 (5) ◽  
pp. 432-438 ◽  
Author(s):  
Cuneyt Ebruli ◽  
Ayşe Nur Demiral ◽  
Riza Çetingöz ◽  
Ferhat Eyiler ◽  
Münir Kinay
Keyword(s):  
Cervical Cancer ◽  
Standard Deviation ◽  
Dose Rate ◽  
Univariate Analysis ◽  
Locally Advanced ◽  
High Dose Rate ◽  
Intracavitary Brachytherapy ◽  
High Dose ◽  
Advanced Cervical Cancer ◽  
Locally Advanced Cervical Cancer

Objective To evaluate the interindividual and intraindividual applicator position variability in high dose rate ring and tandem intracavitary brachytherapy applications in locally advanced cervical cancer. Patients and Methods Eight patients with locally advanced cervical cancer formed the study population. They had been treated in Dokuz Eylül University Department of Radiation Oncology between the years 2000 and 2005 with high dose rate intracavitary brachytherapy using ring and tandem applicators. The 3-dimensional geometric variation of the applicator center in craniocaudal, mediolateral and anteroposterior directions was determined on the basis of bony reference points in 24 pairs of orthogonal films obtained in the conventional simulator. Then the following evaluations were performed: 1) the applicator position variability in all applications (interindividual variability), 2) the intraindividual applicator position variability relative to the first application, 3) the intraindividual applicator position variability relative to the average of three applications. Among the potential factors that might influence the reproducibility of ring and tandem applications, age, stage, the period between external radiotherapy and brachytherapy were evaluated by univariate analysis. Results Standard deviation of interindividual applicator variability was 3.83 mm in craniocaudal, 0.39 mm in mediolateral and 2.86 mm in anteroposterior directions. The standard deviation of intraindividual variability relative to the first application was 1.91 mm in craniocaudal, 0.4 mm in mediolateral, and 4.26 mm in anteroposterior directions. The standard deviation of intraindividual variability relative to the average of three applications was 0.95 mm in craniocaudal, 1.86 mm in mediolateral, and 1.24 mm in anteroposterior directions. According to univariate analysis, no factor influenced applicator position variability. Conclusions In order to extract definitive conclusions about factors that affect positional reproducibility of ring and tandem applicators, studies are needed that include larger numbers of patients.

Template-based high dose rate endobronchial brachytherapy for palliation of previously irradiated obstructive lung lesions.

2016 ◽  
Vol 34 (26_suppl) ◽  
pp. 174-174
Author(s):  
Brian A Hrycushko ◽  
Hsienchang Chiu ◽  
Michael Ryan Folkert
Keyword(s):  
Lung Cancer ◽  
Airway Obstruction ◽  
Dose Rate ◽  
Treatment Planning ◽  
Treatment Time ◽  
High Dose Rate ◽  
Planning System ◽  
External Beam Radiation ◽  
High Dose ◽  
Prescription Dose

174 Background: Local progression after external beam radiation therapy (RT) for lung cancer may result in clinical compromise from bleeding and/or airway obstruction, and additional RT may be precluded by radiation tolerance. High-dose-rate (HDR) endobronchial brachytherapy (EBT) is an effective salvage treatment for airway obstruction and/or bleeding, but requires significant time and resources; planning and treatment are performed bronchoscopically under anesthesia. We sought to reduce procedure and anesthesia time for EBT through template-based planning. Methods: EBT templates were created using the Brachyvision version 11.0.47 treatment planning system for the Varisource iX Ir-192 afterloader. Plans were optimized for dose uniformity at distance from the source following planning criteria of published works. Nine endobronchial centering tube templates were created for treatment lengths from 2-10 cm (1cm intervals) prescribed to 0.5cm distance from the applicator surface. Results: Standard EBT treatment requires a median of 47 minutes (range 44-49 minutes); 5 minutes for applicator placement and fluoroscopic confirmation, 15-17 minutes for plan design and optimization, 20 minutes for quality assurance and plan check, 2-5 minutes for radiation delivery, and 2 minutes for room clearance and applicator removal. Pre-planned templates were evaluated for plan quality, and achieved >90% of the prescription dose for the entire treatment length at the respective treatment depth. Changes to the prescription dose could be achieved through dwell time scaling. Changes to the prescription depth require re-optimization of the plan with the current templates as a base. Use of template-based planning was expected to reduce overall treatment time by 8-9 minutes (16-20% reduction in overall procedure time, 50-56% reduction in treatment planning time); median observed treatment time was 35 minutes (range 32-38 minutes). Conclusions: Template-based HDR EBT treatment plans were developed for the palliative lung cancer program at our institution. Implementation of template-based plans resulted in reduced procedure and operative time, and are now our standard technique.

A method to check treatment time calculations in Ir-192 high-dose-rate volume implants

1995 ◽  
Vol 22 (9) ◽  
pp. 1499-1500 ◽  
Author(s):  
Jack L. M. Venselaar ◽  
Herman W. J. Bierhuizen ◽  
Rien Klop
Keyword(s):  
Dose Rate ◽  
Treatment Time ◽  
High Dose Rate ◽  
High Dose
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