Preliminary result of definitive radiotherapy in patients with non-small cell lung cancer who have underlying idiopathic pulmonary fibrosis: comparison between X-ray and proton therapy

Kim, Hakyoung; Pyo, Hongryull; Noh, Jae Myoung; Lee, Woojin; Park, Byoungsuk; Park, Hye Yun; Yoo, Hyuk Sang

doi:10.1186/s13014-019-1221-4

Cited by 41 publications

(44 citation statements)

References 13 publications

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“…The good tolerance is believed to be linked to the low dose to normal tissue when using protons for treatment. [1][2][3][4] At the same time, low-dose, frequent and accurate imaging, ideally at the treatment site, is required to ensure a safe delivery of the therapeutic doses. 5,6 Proton therapy treatment planning requires a spatial map of the relative (to water) stopping power (RSP), which in current clinical practice is acquired through a conversion from x-ray computed tomography (CT) images.…”

Section: Introductionmentioning

confidence: 99%

An optimization algorithm for dose reduction with fluence‐modulated proton CT

et al. 2020

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Purpose: Fluence-modulated proton computed tomography (FMpCT) using pencil beam scanning aims at achieving task-specific image noise distributions by modulating the imaging proton fluence spot-by-spot based on an object-specific noise model. In this work, we present a method for fluence field optimization and investigate its performance in dose reduction for various phantoms and image variance targets. Methods: The proposed method uses Monte Carlo simulations of a proton CT (pCT) prototype scanner to estimate expected variance levels at uniform fluence. Using an iterative approach, we calculate a stack of target variance projections that are required to achieve the prescribed image variance, assuming a reconstruction using filtered backprojection. By fitting a pencil beam model to the ratio of uniform fluence variance and target variance, relative weights for each pencil beam can be calculated. The quality of the resulting fluence modulations is evaluated by scoring imaging doses and comparing them to those at uniform fluence, as well as evaluating conformity of the achieved variance with the prescription. For three different phantoms, we prescribed constant image variance as well as two regions-of-interest (ROI) imaging tasks with inhomogeneous image variance. The shape of the ROIs followed typical beam profiles for proton therapy. Results: Prescription of constant image variance resulted in a dose reduction of 8.9% for a homogeneous water phantom compared to a uniform fluence scan at equal peak variance level. For a more heterogeneous head phantom, dose reduction increased to 16.0% for the same task. Prescribing two different ROIs resulted in dose reductions between 25.7% and 40.5% outside of the ROI at equal peak variance levels inside the ROI. Imaging doses inside the ROI were increased by 9.2% to 19.2% compared to the uniform fluence scan, but can be neglected assuming that the ROI agrees with the therapeutic dose region. Agreement of resulting variance maps with the prescriptions was satisfactory. Conclusions: We developed a method for fluence field optimization based on a noise model for a real scanner used in pCT. We demonstrated that it can achieve prescribed image variance targets. A uniform fluence field was shown not to be dose optimal and dose reductions achievable with the proposed method for FMpCT were considerable, opening an interesting perspective for image guidance and adaptive therapy.

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Section: Introductionmentioning

confidence: 99%

An optimization algorithm for dose reduction with fluence‐modulated proton CT

et al. 2020

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“…Furthermore, metformin has been reported to improve responses to chemotherapy or targeted agents in several (pre)clinical studies on NSCLC 15,16,39,40 . In a phase II clinical trial with sorafenib monotherapy for 57 pre-treated Stage IIIB-IV NSCLC patients with a KRAS mutation, a partial response occurred more frequently in the five patients using metformin during treatment compared with the non-users (p=0.01) 41 .…”

Section: Discussionmentioning

confidence: 99%

“…A pathological diagnosis including molecular testing on epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), proto-oncogene receptor tyrosine kinase (ROS1) and PD-1/PD-L1 testing is required. The preferred option depends on the type of tumour (squamous versus non-squamous), EGFR/ALK/ROS1 mutation profile and level of PD-1/PD-L1 expression 40 . In case a patient is unfit for systemic therapy and/or has a symptomatic metastatic lesion, palliative radiotherapy can be given.…”

Section: Treatment Of Recurrent Nsclc and Stage IV Non-small Cell Lunmentioning

confidence: 99%

“…When looking into the risk factors for RR after surgery for early stage NSCLC, there are two types of studies. Most studies have investigated predictive factors for ONM in clinical stage I NSCLC through examination of the resected specimens of the tumour and the lymph nodes 11,[38][39][40][41][42][43] . Identified risk factors for ONM include larger tumour size, solid consistency on high-resolution CT, adenocarcinoma, higher SUV max , increased carcinoembryonic antigen level, visceral pleural invasion (VPI), and poor pathological differentiation.…”

Section: Incidence Of Regional Recurrence and Risk Factors Derived Frmentioning

confidence: 99%

“…Several techniques (rescanning, gating, tracking) trying to compensate for the interplay effect are topic of intensive research in several groups worldwide. For IMPT, the robustness and a geometrical tumour tracking method mitigating to motion were evaluated in 7 NSCLC patients treated to 45 GyE in 3 fractions 40 .…”

Section: Proton Therapy Techniques and Considerations For Treatment Pmentioning

confidence: 99%

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