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.

scholarly journals High dose-rate brachytherapy treatment delivery: Report of the AAPM Radiation Therapy Committee Task Group No. 59

1998 ◽  
Vol 25 (4) ◽  
pp. 375-403 ◽  
Author(s):  
H. Dale Kubo ◽  
Glenn P. Glasgow ◽  
Timothy D. Pethel ◽  
Bruce R. Thomadsen ◽  
Jeffrey F. Williamson
Keyword(s):  
Radiation Therapy ◽  
Dose Rate ◽  
High Dose Rate ◽  
Task Group ◽  
High Dose ◽  
High Dose Rate Brachytherapy ◽  
Treatment Delivery

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.

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