scholarly journals Lung Stereotactic Body Radiotherapy (SBRT) Using Spot-Scanning Proton Arc (SPArc) Therapy: A Feasibility Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Gang Liu ◽  
Lewei Zhao ◽  
An Qin ◽  
Inga Grills ◽  
Rohan Deraniyagala ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Stereotactic Body Radiotherapy ◽  
Normal Tissue ◽  
Lung Tumor ◽  
Internal Target Volume ◽  
Normal Tissue Sparing ◽  
Spot Scanning ◽  
Interplay Effect ◽  
Tissue Sparing ◽  
Motion Amplitude

PurposeWe developed a 4D interplay effect model to quantitatively evaluate breathing-induced interplay effects and assess the feasibility of utilizing spot-scanning proton arc (SPArc) therapy for hypo-fractionated lung stereotactic body radiotherapy (SBRT). The model was then validated by retrospective application to clinical cases.Materials and MethodsA digital lung 4DCT phantoms was used to mimic targets in diameter of 3cm with breathing motion amplitudes: 5, 10, 15, and 20 mm, respectively. Two planning groups based on robust optimization were generated: (1) Two-field Intensity Modulated Proton Therapy (IMPT) plans and (2) SPArc plans via a partial arc. 5,000 cGy relative biological effectiveness (RBE) was prescribed to the internal target volume (ITV) in five fractions. To quantitatively assess the breathing induced interplay effect, the 4D dynamic dose was calculated by synchronizing the breathing pattern with the simulated proton machine delivery sequence, including IMPT, Volumetric repainting (IMPTvolumetric), iso-layered repainting (IMPTlayer) and SPArc. Ten lung patients’ 4DCT previously treated with VMAT SBRT, were used to validate the digital lung tumor model. Normal tissue complicated probability (NTCP) of chestwall toxicity was calculated.ResultTarget dose were degraded as the tumor motion amplitude increased. The 4D interplay effect phantom model indicated that motion mitigation effectiveness using SPArc was about five times of IMPTvolumetric or IMPTlayer using maximum MU/spot as 0.5 MU at 20 mm motion amplitude. The retrospective study showed that SPArc has an advantage in normal tissue sparing. The probability of chestwall’s toxicity were significantly improved from 40.2 ± 29.0% (VMAT) (p = 0.01) and 16.3 ± 12.0% (IMPT) (p = 0.01) to 10.1 ± 5.4% (SPArc). SPArc could play a significant role in the interplay effect mitigation with breathing-induced motion more than 20 mm, where the target D99 of 4D dynamic dose for patient #10 was improved from 4,514 ± 138 cGy [RBE] (IMPT) vs. 4,755 ± 129 cGy [RBE] (SPArc) (p = 0.01).ConclusionSPArc effectively mitigated the interplay effect for proton lung SBRT compared to IMPT with repainting and was associated with normal tissue sparing. This technology may make delivery of proton SBRT more technically feasible and less complex with fewer concerns over underdosing the target compared to other proton therapy techniques.

PD-0347 EXTENDED PENUMBRA REDUCTION FOR NORMAL TISSUE SPARING IN PROTON THERAPY OF INTRACRANIAL TUMOR

2012 ◽  
Vol 103 ◽  
pp. S139 ◽  
Author(s):  
M. Bubula ◽  
U. Jelen ◽  
F. Ammazzalorso ◽  
U. Weber ◽  
K. Zink ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Normal Tissue ◽  
Intracranial Tumor ◽  
Normal Tissue Sparing ◽  
Tissue Sparing

scholarly journals The normal tissue sparing obtained with simultaneous treatment of pelvic lymph nodes and bladder using intensity-modulated radiotherapy

2009 ◽  
Vol 48 (2) ◽  
pp. 238-244 ◽  
Author(s):  
Jimmi Søndergaard ◽  
Morten Høyer ◽  
Jørgen B. Petersen ◽  
Pauliina Wright ◽  
Cai Grau ◽  
...  
Keyword(s):  
Lymph Nodes ◽  
Normal Tissue ◽  
Intensity Modulated Radiotherapy ◽  
Simultaneous Treatment ◽  
Pelvic Lymph Nodes ◽  
Intensity Modulated ◽  
Normal Tissue Sparing ◽  
Tissue Sparing

scholarly journals Normal tissue sparing using different techniques for prostate irradiation

2020 ◽  
Vol 25 (1) ◽  
pp. 85-90
Author(s):  
Barbara Melles-Bencsik ◽  
Tamás Pócza ◽  
Tibor Major ◽  
Péter Ágoston ◽  
Kliton Jorgo ◽  
...  
Keyword(s):  
Normal Tissue ◽  
Normal Tissue Sparing ◽  
Tissue Sparing

scholarly journals Influence of Target Location, Size, and Patient Age on Normal Tissue Sparing- Proton and Photon Therapy in Paediatric Brain Tumour Patient-Specific Approach

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2578
Author(s):  
Mikaela Dell’Oro ◽  
Michala Short ◽  
Puthenparampil Wilson ◽  
Chia-Ho Hua ◽  
Melissa Gargone ◽  
...  
Keyword(s):  
Normal Tissue ◽  
Optic Chiasm ◽  
Patient Specific ◽  
Patient Age ◽  
Dose Distributions ◽  
Intensity Modulated ◽  
Normal Tissue Sparing ◽  
Patient Âgé ◽  
Tissue Sparing ◽  
Photon Radiotherapy

Background: Proton radiotherapy produces superior dose distributions compared to photon radiotherapy, reducing side effects. Differences between the two modalities are not fully quantified in paediatric patients for various intracranial tumour sites or age. Understanding these differences may help clinicians estimate the benefit and improve referral across available centres. Our aim was to compare intensity-modulated proton therapy (IMPT) and intensity-modulated photon radiotherapy (IMRT) radiation doses for select paediatric intracranial tumours. Methods: IMPT and IMRT dose distributions for gender-matched paediatric cranial CT-datasets (ages 5, 9 and 13 years) were retrospectively calculated to simulate irradiation of supratentorial (ependymoma) and infratentorial (medulloblastoma) target volumes diameters (1–3 cm) and position (central and 1–2 cm shifts). Results: Clinical dosimetric objectives were achieved for all 216 treatment plans. Whilst infratentorial IMPT plans achieved greater maximum dose sparing to optic structures (4.8–12.6 Gy optic chiasm), brainstem sparing was limited (~0.5 Gy). Mean dose difference for optic chiasm was associated with medulloblastoma target position (p < 0.0197). Supratentorial IMPT plans demonstrated greater dose reduction for the youngest patients (pituitary gland p < 0.001). Conclusions: Normal tissue sparing was achieved regardless of patient age for infratentorial tumours. However, for supratentorial tumours, there was a dosimetric advantage of IMPT across 9 vs. 13-year-old patients.

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