scholarly journals Quantification of an External Motion Surrogate for Quality Assurance in Lung Cancer Radiation Therapy

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Jens Wölfelschneider ◽  
Tobias Brandt ◽  
Sebastian Lettmaier ◽  
Rainer Fietkau ◽  
Christoph Bert
Keyword(s):  
Quality Assurance ◽  
Radiation Therapy ◽  
Global Minimum ◽  
Tumor Volume ◽  
Lung Tumor ◽  
Free Breathing ◽  
Breath Hold ◽  
Target Volumes ◽  
Posterior Direction ◽  
The Stability

The purpose of this work was to validate the stability of the end exhale position in deep expiration breath hold (DEBH) technique for quality assurance in stereotactic lung tumor radiation therapy. Furthermore, a motion analysis was performed for 20 patients to evaluate breathing periods and baseline drifts based on an external surrogate. This trajectory was detected using stereo infrared (IR) cameras and reflective body markers. The respiratory waveform showed large interpatient differences in the end exhale position during irradiation up to 18.8 mm compared to the global minimum. This position depends significantly on the tumor volume. Also the baseline drifts, which occur mostly in posterior direction, are affected by the tumor size. Breathing periods, which depend mostly on the patient age, were in a range between 2.4 s and 7.0 s. Fifteen out of 20 patients, who showed a reproducible end exhale position with a deviation of less than 5 mm, might benefit from DEBH due to smaller planning target volumes (PTV) compared to free breathing irradiation and hence sparing of healthy tissue. Patients with larger uncertainties should be treated with more complex motion compensation techniques.

scholarly journals Recent advances in Surface Guided Radiation Therapy

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
P. Freislederer ◽  
M. Kügele ◽  
M. Öllers ◽  
A. Swinnen ◽  
T.-O. Sauer ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Radiation Therapy ◽  
Imaging Technique ◽  
Patient Treatment ◽  
Quality Assurance Program ◽  
Breath Hold ◽  
Breast Irradiation ◽  
Clinical Practices ◽  
Motion Management ◽  
Wide Range

Abstract The growing acceptance and recognition of Surface Guided Radiation Therapy (SGRT) as a promising imaging technique has supported its recent spread in a large number of radiation oncology facilities. Although this technology is not new, many aspects of it have only recently been exploited. This review focuses on the latest SGRT developments, both in the field of general clinical applications and special techniques. SGRT has a wide range of applications, including patient positioning with real-time feedback, patient monitoring throughout the treatment fraction, and motion management (as beam-gating in free-breathing or deep-inspiration breath-hold). Special radiotherapy modalities such as accelerated partial breast irradiation, particle radiotherapy, and pediatrics are the most recent SGRT developments. The fact that SGRT is nowadays used at various body sites has resulted in the need to adapt SGRT workflows to each body site. Current SGRT applications range from traditional breast irradiation, to thoracic, abdominal, or pelvic tumor sites, and include intracranial localizations. Following the latest SGRT applications and their specifications/requirements, a stricter quality assurance program needs to be ensured. Recent publications highlight the need to adapt quality assurance to the radiotherapy equipment type, SGRT technology, anatomic treatment sites, and clinical workflows, which results in a complex and extensive set of tests. Moreover, this review gives an outlook on the leading research trends. In particular, the potential to use deformable surfaces as motion surrogates, to use SGRT to detect anatomical variations along the treatment course, and to help in the establishment of personalized patient treatment (optimized margins and motion management strategies) are increasingly important research topics. SGRT is also emerging in the field of patient safety and integrates measures to reduce common radiotherapeutic risk events (e.g. facial and treatment accessories recognition). This review covers the latest clinical practices of SGRT and provides an outlook on potential applications of this imaging technique. It is intended to provide guidance for new users during the implementation, while triggering experienced users to further explore SGRT applications.

Fraction-specific post-treatment quality assurance for active breath-hold radiation therapy

2019 ◽  
Vol 18 (03) ◽  
pp. 262-270
Author(s):  
Rajesh Thiyagarajan ◽  
Arunai Nambiraj ◽  
Durai Manigandan ◽  
Tamilseivan Singaravelu ◽  
Rajesh Selvaraj ◽  
...  
Keyword(s):  
Quality Assurance ◽  
Radiation Therapy ◽  
Intensity Modulated Radiation Therapy ◽  
Post Treatment ◽  
Patient Comfort ◽  
Treatment Quality ◽  
Patient Specific ◽  
Breath Hold ◽  
Therapist Communication ◽  
Dosimetric System

AbstractPurposeThe purpose of this study is to evaluate variation in the treatment hold pattern and quantify its dosimetric impact in breath-hold radiotherapy, using fraction-specific post-treatment quality assurance.Material and MethodsA patient with lung mets treated using intensity-modulated radiation therapy (IMRT) with active breath coordinator (ABC) was recruited for the study. Treatment beam hold conditions were recorded for all the 25 fractions. The linearity and reproducibility of the dosimetric system were measured. Variation in the dose output of unmodulated open beam with beam hold was studied. Patient-specific quality assurance (PSQA) was performed with and without beam hold, and the results were compared to quantify the dosimetric impact of beam hold.ResultsThere was a considerable amount of variation observed in the number of beam hold for the given field and the monitor unit at which the beam held. Linearity and reproducibility of the dosimetric system were found within the acceptable limits. The average difference over the 25 measurements was 0·044% (0·557 to −0·318%) with standard deviation of 0·248.ConclusionPatient comfort with the ABC system and responsiveness to the therapist communication help to maintain consistent breathing pattern, in turn consistent treatment delivery pattern. However, the magnitude of dosimetric error is much less than the acceptable limits recommended by IROC. The dosimetric error induced by the beam hold is over and above the dose difference observed in conventional PSQA.

scholarly journals Dosimetric comparison of deep inspiration breath hold and free breathing technique in stereotactic body radiotherapy for localized lung tumor using Flattening Filter Free beam

2018 ◽  
Vol 24 (1) ◽  
pp. 15-24 ◽  
Author(s):  
Karthick Raj Mani ◽  
Md. Anisuzzaman Bhuiyan ◽  
Md. Mahbub Alam ◽  
Sharif Ahmed ◽  
Mostafa Aziz Sumon ◽  
...  
Keyword(s):  
Lung Tumor ◽  
Free Breathing ◽  
Target Volume ◽  
Breath Hold ◽  
Deep Inspiration ◽  
Deep Inspiration Breath Hold ◽  
Ipsilateral Lung ◽  
Flattening Filter Free ◽  
Flattening Filter ◽  
The Mean

Abstract Aim: To compare the dosimetric advantage of stereotactic body radiotherapy (SBRT) for localized lung tumor between deep inspiration breath hold technique and free breathing technique. Materials and methods: We retrospectively included ten previously treated lung tumor patients in this dosimetric study. All the ten patients underwent CT simulation using 4D-CT free breathing (FB) and deep inspiration breath hold (DIBH) techniques. Plans were created using three coplanar full modulated arc using 6 MV flattening filter free (FFF) bream with a dose rate of 1400 MU/min. Same dose constraints for the target and the critical structures for a particular patient were used during the plan optimization process in DIBH and FB datasets. We intend to deliver 50 Gy in 5 fractions for all the patients. For standardization, all the plans were normalized at target mean of the planning target volume (PTV). Doses to the critical structures and targets were recorded from the dose volume histogram for evaluation. Results: The mean right and left lung volumes were inflated by 1.55 and 1.60 times in DIBH scans compared to the FB scans. The mean internal target volume (ITV) increased in the FB datasets by 1.45 times compared to the DIBH data sets. The mean dose followed by standard deviation (x̄ ± σx̄) of ipsilateral lung for DIBH-SBRT and FB-SBRT plans were 7.48 ± 3.57 (Gy) and 10.23 ± 4.58 (Gy) respectively, with a mean reduction of 36.84% in DIBH-SBRT plans. Ipsilateral lung were reduced to 36.84% in DIBH plans compared to FB plans. Conclusion: Significant dose reduction in ipsilateral lung due to the lung inflation and target motion restriction in DIBH-SBRT plans were observed compare to FB-SBRT. DIBH-SBRT plans demonstrate superior dose reduction to the normal tissues and other critical structures.

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