Dosimetric Uncertainties in Dominant Intraprostatic Lesion Simultaneous Boost Using Intensity Modulated Proton Therapy

Zhou, Jun; Yang, Xiaofeng; Chang, Chung‐Cheng; Tian, Sibo; Wang, Tonghe; Lin, Liyong; Wang, Yinan; Janopaul‐Naylor, James; Patel, Pretesh; Demoor, J.; Bohannon, Duncan; Stanforth, Alex; Eaton, Bree R.; McDonald, Mark W.; Liu, Tian; Patel, Sagar

doi:10.1016/j.adro.2021.100826

Cited by 7 publications

(8 citation statements)

References 43 publications

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“…Further, based on an analysis using Surveillance, Epidemiology, and End Results data, disparities in definitive treatment rates could be more profound amongst Black men with low compared to high income 38 . Beyond the standard of care, non‐White men are significantly underrepresented on clinical trials and have lower utilization of advanced radiotherapy techniques such as proton therapy 39–45 . The structural racism that Black patients face across healthcare settings perpetuates the disparate access and outcomes 12,46,47 .…”

Section: Discussionmentioning

confidence: 99%

Disparities in time to prostate cancer treatment initiation before and after the Affordable Care Act

et al. 2023

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BackgroundDelayed access to care may contribute to disparities in prostate cancer (PCa). The Affordable Care Act (ACA) aimed at increasing access and reducing healthcare disparities, but its impact on timely treatment initiation for PCa men is unknown.MethodsMen with intermediate‐ and high‐risk PCa diagnosed 2010–2016 and treated with curative surgery or radiotherapy were identified in the National Cancer Database. Multivariable logistic regression modeled the effect of race and insurance type on treatment delay >180 days after diagnosis. Cochran–Armitage test measured annual trends in delays, and joinpoint regression assessed if 2014, the year the ACA became fully operationalized, was significant for inflection in crude rates of major delays.ResultsOf 422,506 eligible men, 18,720 (4.4%) experienced >180‐day delay in treatment initiation. Compared to White patients, Black (OR 1.79, 95% CI 1.72–1.87, p < 0.001) and Hispanic (OR 1.37, 95% CI 1.28–1.48, p < 0.001) patients had higher odds of delay. Compared to uninsured, those with Medicaid had no difference in odds of delay (OR 0.94, 95% CI 0.84–1.06, p = 0.31), while those with private insurance (OR 0.57, 95% CI 0.52–0.63, p < 0.001) or Medicare (OR 0.64, 95% CI 0.58–0.70, p < 0.001) had lower odds of delay. Mean time to treatment significantly increased from 2010 to 2016 across all racial/ethnic groups (trend p < 0.001); 2014 was associated with a significant inflection for increase in rates of major delays.ConclusionsNon‐White and Medicaid‐insured men with localized PCa are at risk of treatment delays in the United States. Treatment delays have been consistently rising, particularly after implementation of the ACA.

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Section: Discussionmentioning

confidence: 99%

Disparities in time to prostate cancer treatment initiation before and after the Affordable Care Act

et al. 2023

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“…The treatment plan, that is, designed based on the patient's original anatomy can result in mispositioned Bragg peaks in the patient's current anatomy, leading to the underdosing of tumors and/or overdosing of the critical organs. Although robust plan optimization 4 can account for the anatomical changes to some extent, this method can maintain the designed plan quality only when the bounding scenarios cover the patient's actual treatment anatomy during the robust optimization 5,6 . Adaptive proton therapy (APT) offers a general solution for patients’ anatomical changes without increasing the dose to critical organs and normal tissues 7 .…”

Section: Introductionmentioning

confidence: 99%

A retrospective study on the investigation of potential dosimetric benefits of online adaptive proton therapy for head and neck cancer

Chang,

Bohannon,

Tian

et al. 2024

J Applied Clin Med Phys

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PurposeProton therapy is sensitive to anatomical changes, often occurring in head‐and‐neck (HN) cancer patients. Although multiple studies have proposed online adaptive proton therapy (APT), there is still a concern in the radiotherapy community about the necessity of online APT. We have performed a retrospective study to investigate the potential dosimetric benefits of online APT for HN patients relative to the current offline APT.MethodsOur retrospective study has a patient cohort of 10 cases. To mimic online APT, we re‐evaluated the dose of the in‐use treatment plan on patients’ actual treatment anatomy captured by cone‐beam CT (CBCT) for each fraction and performed a templated‐based automatic replanning if needed, assuming that these were performed online before treatment delivery. Cumulative dose of the simulated online APT course was calculated and compared with that of the actual offline APT course and the designed plan dose of the initial treatment plan (referred to as nominal plan). The ProKnow scoring system was employed and adapted for our study to quantify the actual quality of both courses against our planning goals.ResultsThe average score of the nominal plans over the 10 cases is 41.0, while those of the actual offline APT course and our simulated online course is 25.8 and 37.5, respectively. Compared to the offline APT course, our online course improved dose quality for all cases, with the score improvement ranging from 0.4 to 26.9 and an average improvement of 11.7.ConclusionThe results of our retrospective study have demonstrated that online APT can better address anatomical changes for HN cancer patients than the current offline replanning practice. The advanced artificial intelligence based automatic replanning technology presents a promising avenue for extending potential benefits of online APT.

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“…Proton Monte Carlo (MC) treatment planning system required a Hounsfield lookup table for computed tomography (CT)-tomaterial conversion [2,3], which contributes approximately 2.5% range uncertainty [4]. For proton therapy, MC robust treatment planning usually adopts a 3.5% range uncertainty and a positional uncertainty of 3-7 mm [5]. Those uncertainties result in a conservative treatment margin that may compromise the sparing of healthy tissues, for instance, spine vertebrae, such as craniospinal irradiation (CSI) patients [6,7].…”

Section: Introductionmentioning

confidence: 99%

In vivo proton range validation using pseudo proton radiography

Chang

Zhou

Gao

et al. 2023

Medical Imaging 2023: Physics of Medical Imaging

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The current clinical practice for Monte Carlo (MC) treatment planning reserves a 3.5% margin to compensate for proton range uncertainty. Additionally, patient positional uncertainty is typically 3-5 mm for proton craniospinal irradiation (CSI) treatment planning. These two uncertainties compromise the sparing of spine vertebrae in proton CSI patients. Computer tomography (CT) material characterization contributes approximately 2.5% proton range uncertainty. Multiple CT-tomaterial conversion methods have been investigated using dual-energy CT or magnetic resonance imaging to improve the range uncertainty. However, there is a lack of experimental data to validate the credibility of those material characterization models. We aim to develop an in vivo proton range method using pseudo proton radiography to validate imaging-based material characterization models consistently. Proton radiography techniques, such as proton water equivalent thickness (WET) and dose maps, were used to evaluate the in vivo proton range accuracy. Anteroposterior proton beams were penetrated through an anthropomorphic phantom. Then the exit doses were measured from proton radiography imaging. The validation experiment applied a newly designed multi-layer strip ionization chamber (MLSIC) for the first time to perform four-dimensional (4D) measurement for depth doses from 625 proton spots in two minutes. The depth doses of each spot were post-processed into WET imaging. A MatriXX PT was applied for 2D measurement from 19x19 cm2 proton fields. We compared the performance of the empirical DECT model and physics-informed machine learning (PIML) models for material conversion. The results indicated that the PIML-based material characteristic method generated more accurate WET and dose imaging using DECT compared to conventional machine learning and empirical material inference methods. The proposed in vivo proton range validation method can be used to quantify the credibility of DECT-based material conversion models for proton range enhancement. The method can potentially provide in-room patient anatomy changes to accomplish online adaption for modification. This technique will significantly benefit proton flash therapy, which demands high accuracy.

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Dosimetric Uncertainties in Dominant Intraprostatic Lesion Simultaneous Boost Using Intensity Modulated Proton Therapy

Abstract: Dosimetric uncertainties in dominant intraprostatic lesion simultaneous boost using intensity modulated proton therapy, Advances in Radiation Oncology (2021), doi:

Cited by 7 publications

References 43 publications

Disparities in time to prostate cancer treatment initiation before and after the Affordable Care Act

Disparities in time to prostate cancer treatment initiation before and after the Affordable Care Act

A retrospective study on the investigation of potential dosimetric benefits of online adaptive proton therapy for head and neck cancer

In vivo proton range validation using pseudo proton radiography

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