Markerless 3D tumor tracking during single-fraction free-breathing 10MV flattening-filter-free stereotactic lung radiotherapy

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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Flattening filter free (FFF) rapid arc for single fraction SBRT of the lung reduces treatment time and is dosimetrically equivalent to flattening filter VMAT

Physica Medica ◽

10.1016/j.ejmp.2016.01.011 ◽

2016 ◽

Vol 32 ◽

pp. 2-3

Author(s):

S. Barbiero ◽

F. Matteucci ◽

D. Fedele ◽

M. Avanzo

Keyword(s):

Treatment Time ◽

Single Fraction ◽

Flattening Filter Free ◽

Flattening Filter

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Single-fraction flattening filter–free volumetric modulated arc therapy for lung cancer: Dosimetric results and comparison with flattened beams technique

Medical Dosimetry ◽

10.1016/j.meddos.2016.09.002 ◽

2016 ◽

Vol 41 (4) ◽

pp. 334-338 ◽

Cited By ~ 6

Author(s):

Sara Barbiero ◽

Alexandra Rink ◽

Fabrizio Matteucci ◽

David Fedele ◽

Fabiola Paiar ◽

...

Keyword(s):

Lung Cancer ◽

Volumetric Modulated Arc Therapy ◽

Single Fraction ◽

Flattening Filter Free ◽

Arc Therapy ◽

Flattening Filter

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Dosimetric comparison of flattened and flattening filter-free beams for liver stereotactic body irradiation in deep inspiration breath hold, and free breathing conditions

Journal of Radiotherapy in Practice ◽

10.1017/s146039691800064x ◽

2019 ◽

Vol 18 (02) ◽

pp. 169-174

Author(s):

N. Munirathinam ◽

P. N. Pawaskar

Keyword(s):

Free Breathing ◽

Target Volume ◽

Conformity Index ◽

Breath Hold ◽

Deep Inspiration ◽

Deep Inspiration Breath Hold ◽

Flattening Filter Free ◽

Treatment Plans ◽

Flattening Filter ◽

Prescription Dose

AbstractAimThe aim of this study is to evaluate the influence of flattened and flattening filter-free (FFF) beam 6 MV photon beam for liver stereotactic body radiation therapy by using volumetric modulated arc therapy (VMAT) technique in deep inspiration breath hold (DIBH) and free breathing condition.Materials and methodsEight liver metastasis patients (one to three metastasis lesions) were simulated in breath hold and free breathing condition. VMAT-based treatment plans were created for a prescription dose of 50 Gy in 10 fractions, using a 230° coplaner arc and 60° non-coplanar arc for both DIBH and free breathing study set. Treatment plans were evaluated for planning target volume (PTV) dose coverage, conformity and hot spots. Parallel and serial organs at risk were compared for average and maximum dose, respectively. Dose spillages were evaluated for different isodose volumes from 5 to 80%.ResultMean D 98% (dose received by 98% target volume) for FFF in DIBH, flattened beam in DIBH, FFF in free breathing and flatten beam in free breathing dataset were 48·9, 47·81, 48·5 and 48·3 Gy, respectively. D 98% was not statistically different between FFF and flatten beam (p = 0·34 and 0·69 for DIBH and free breathing condition). PTV V 105% (volume receiving 105% dose) for the same set were 3·76, 0·25, 1·2 and 0·4%, respectively. Mean heterogeneity index for all study sets and beam models varies between 1·05 and 1·07. Paddik conformity index using unflattened and flattened beam in DIBH at 98% prescription dose were 0·91 and 0·79, respectively. Maximum variation of isodose volume was observed for I-5%, which was ranging between 2288·8 and 2427·2 cm3. Increase in isodose value shows a diminishing difference in isodose volumes between different techniques. DIBH yields a significant reduction in the chest wall dose compared with free breathing condition. Average monitor units for FFF beam in DIBH, flattened beam in DIBH, FFF beam in free breathing CT dataset and flattened beam in free breathing CT dataset were 1318·6 ± 265·1, 1940·3 ± 287·6, 1343·3 ± 238·1 and 2192·5 ± 252·6 MU.ConclusionDIBH and FFF is a good combination to reduce the treatment time and to achieve better tumour conformity. No other dosimetric gain was observed for FFF in either DIBH or free breathing condition.

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Dosimetric superiority of flattening filter free beams for single-fraction stereotactic radiosurgery in single brain metastasis

Oncotarget ◽

10.18632/oncotarget.13085 ◽

2016 ◽

Vol 8 (21) ◽

pp. 35272-35279 ◽

Cited By ~ 5

Author(s):

Youqun Lai ◽

Shanyu Chen ◽

Changdong Xu ◽

Liwan Shi ◽

Lirong Fu ◽

...

Keyword(s):

Brain Metastasis ◽

Stereotactic Radiosurgery ◽

Single Fraction ◽

Flattening Filter Free ◽

Single Brain Metastasis ◽

Flattening Filter

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Flattening filter free Stereotactic radiosurgery for brain metastases using dynamic conformal arcs: 6 MV or 10 MV?

Journal of Radiotherapy in Practice ◽

10.1017/s1460396920001247 ◽

2021 ◽

pp. 1-7

Author(s):

Glenn Whitten ◽

Ursula Daly ◽

Candice D. McCallum ◽

Jackie Harney ◽

David Conkey ◽

...

Keyword(s):

Brain Metastases ◽

Stereotactic Radiosurgery ◽

Treatment Time ◽

High Dose ◽

Normal Brain ◽

Plan Quality ◽

Single Fraction ◽

Flattening Filter Free ◽

Intracranial Lesions ◽

Flattening Filter

Abstract Introduction: Stereotactic radiosurgery (SRS) has proven itself as an effective tool in the treatment of intracranial lesions. Image-guided high dose single fraction treatments have the potential to deliver ablative doses to tumours; however, treatment times can be long. Flattening filter free (FFF) beams are available on most modern linacs and offer a higher dose rate compared to conventional flattened beams which should reduce treatment times. This study aimed to compare 6 MV FFF and 10 MV FFF to a 6 MV flattened beam for single fraction dynamic conformal arc SRS for a Varian Truebeam linac. Materials and methods: In total, 21 individual clinical treatment plans for 21 brain metastases treated with 6 MV were retrospectively replanned using both 6 MV FFF and 10 MV FFF. Plan quality and efficiency metrics were evaluated by analysing dose coverage, dose conformity, dose gradients, dose to normal brain, beam-on-time (BOT), treatment time and monitor units. Results: FFF resulted in a significant reduction in median BOT for both 6 MV FFF (57·9%; p < 0·001) and 10 MV FFF (76·3%; p < 0·001) which led to reductions in treatment times of 16·8 and 21·5% respectively. However, 6 MV FFF showed superior normal brain dose sparing (p < 0·001) and dose gradient (p < 0·001) compared to 10 MV FFF. No differences were observed for conformity. Conclusion: 6 MV FFF offers a significant reduction in average treatment time compared to 6 MV (3·7 minutes; p = 0·002) while maintaining plan quality.

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