Physics and Imaging in Radiation Oncology最新文献_第4页

Modeling dose uncertainty in cone-beam computed tomography: Predictive approach for deep learning-based synthetic computed tomography generation

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100704

Cédric Hémon, Lucía Cubero, Valentin Boussot, Romane-Alize Martin, Blanche Texier, Joël Castelli, Renaud de Crevoisier, Anaïs Barateau, Caroline Lafond, Jean-Claude Nunes

Background and purpose:

Cone-beam computed tomography (CBCT) is essential in image-guided radiotherapy (RT) for patient positioning and daily dose calculation. However, CT numbers in CBCT fluctuate and differ from those in computed tomography (CT), requiring synthetic CT (sCT) generation to improve dose calculation accuracy. CBCT-to-sCT synthesis remains a challenging and uncertain task in clinical practice. This study aims to introduce a voxel-wise uncertainty estimator correlated with the error between sCT and CT.

Material and Methods:

Eighty-five head and neck (H&N) patients treated with photon RT from a single center were selected for developing and validating our uncertainty estimation method. To test the method’s robustness on out-of-distribution images, three additional patients from different centers were included. Our proposed uncertainty estimation method builds on established conventional techniques. Additionally, to explore potential error scenarios, we generated several ‘plausible’ sCTs representing variations in sCT generation caused by CBCT quality differences. This allowed us to quantify dose uncertainties.

Results:

The effectiveness of uncertainty maps was evaluated by correlating them with the absolute error map between sCT and CT, yielding a Pearson correlation coefficient between 0.65 and 0.72. Dose uncertainty was determined on the dose-volume histogram (DVH). For all patients except one, the reference CT DVH was included in the uncertainty interval defined by the sCT-derived DVH.

Conclusions:

Our proposed methods effectively predict uncertainty maps that aid in evaluating sCT quality. This approach also provides a novel method for estimating dose uncertainty by defining a confidence interval around the CT DVH using the estimated sCT uncertainty.

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引用次数: 0

Corrigendum to “Explicitly encoding the cyclic nature of breathing signal allows for accurate breathing motion prediction in radiotherapy with minimal training data” [Phys. Imaging Radiat. Oncol. 30 (2024) 100594]

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100718

Andreas Renner , Ingo Gulyas , Martin Buschmann , Gerd Heilemann , Barbara Knäusl , Martin Heilmann , Joachim Widder , Dietmar Georg , Petra Trnková

引用次数: 0

Accuracy-dependent dose-constraints and dose-based safety margins for organs-at-risk in radiotherapy

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100713

Joep C. Stroom , Sandra C. Vieira , Carlo Greco , Sebastiaan M.J.J.G. Nijsten

Background and purpose

Geometrical uncertainties in radiotherapy are generally accounted for by margins for tumors, but their effect on organs-at-risk (OARs) is often ignored. We developed a model that incorporates dose- and geometry-based uncertainties in OAR planning using dose constraints.

Materials and methods

Radiotherapy uncertainties cause real dose-volume histograms (DVHs) to spread around the planned DVH. With a published OAR dose constraint D(V_crit) < D_crit such that complication probability < Y%, real differences from planned D_crit can be described by mean- (MD_Dcrit) and standard deviations (SD_Dcrit). Assuming complications are associated with the worst DVHs, New dose constraints that maintain complication probability can be derived for new treatments:D_crit,New = D_crit,publ + Φ⁻¹(1 - Y%) * (SD_Dcrit,publ - SD_Dcrit,New) + (MD_Dcrit,publ - MD_Dcrit,New),with Φ⁻¹(x) the inverse cumulative normal distribution function. Setting SD_Dcrit,New = MD_Dcrit,New = 0 in the recipe yields the “True” critical dose, and D_crit,True - D_crit,publ can be considered a dose-based safety margin (DSM).

As hypothetical example, we estimated MD_Dcrit and SD_Dcrit values by simulating geometric errors in our clinical treatment plans and adding dose-based uncertainty. Over 1000 OARs with 108 different regular- and hypo-fractionation constraints were simulated. We assumed accuracy SDs to change from 2.5mm/3% to 1.5mm/2%.

Results

Results varied per OAR, fractionation, and constraint-type. If our 2.5mm/3% MD_Dcrit and SD_Dcrit values approximated dose-constraint studies, on average the DSM would be 4.5 Gy (18%) and our dose constraints would increase with 1.2 Gy (5%).

Conclusions

We introduced a first model relating dose constraints and complication probabilities with treatment uncertainties and safety margins for OARs. Among other things, it quantified how higher constraints can be applied with increasing radiotherapy accuracy.

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引用次数: 0

A novel multimodality anthropomorphic phantom enhances compliance with quality assurance guidelines for magnetic resonance imaging in radiotherapy

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100707

Meshal Alzahrani , David A Broadbent , Irvin Teh , Bashar Al-Qaisieh , Emily Johnstone , Richard Speight

Background and purpose

The use of magnetic resonance imaging (MRI) for radiotherapy (RT) simulation has grown, prompting quality assurance (QA) guidelines by the Institute of Physics and Engineering in Medicine (IPEM) and the American Association of Physicists in Medicine (AAPM). This study compares a novel multimodality anthropomorphic phantom to an American College of Radiology (ACR) phantom for a subset of these MRI-specific QA tests in RT.

Materials and methods

A novel 3D-printed multimodality head-and-neck anthropomorphic phantom was compared to an ACR large MRI phantom. IPEM and AAPM-recommended QA tests were conducted, including informatics/connectivity/data transfer, MRI-CT registration, end-to-end QA, and signal-to-noise ratio (SNR)/percentage integral uniformity (PIU) assessments using RT accessories.

Results

Both phantoms were suitable for informatics/connectivity/data transfer. In MRI-CT registration, no errors were found; the ACR phantom offered more quantitative landmarks, while the anthropomorphic phantom provided limited structures. Both phantoms achieved target registration errors (TREs) below 0.97 mm and dice similarity coefficient (DSC) values above 0.9, meeting guidelines. For end-to-end QA, the anthropomorphic phantom facilitated dose measurements of 1.994 Gy versus a calculated 2.01 Gy (−0.8 %). SNR and PIU assessments showed higher values in radiology setups compared to RT setups for both phantoms.

Conclusions

Multimodality anthropomorphic phantoms compatible with dosimetric equipment allow realistic end-to-end QA, unlike the ACR phantom. While the ACR phantom is suitable for informatics and MRI-CT registration, anthropomorphic phantoms better represent clinical scenarios. For comprehensive QA, both ACR and anthropomorphic phantoms are required. Additionally, large field-of-view (FOV) phantoms are crucial for evaluating large FOV MRI distortions.

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引用次数: 0

Quantitative magnetic resonance imaging responses in head and neck cancer patients treated with magnetic resonance-guided hypofractionated radiation therapy

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2024.100693

Ryan Bonate , Musaddiq J. Awan , Heather A. Himburg , Stuart Wong , Monica Shukla , Sergey Tarima , Joseph Zenga , Eric S. Paulson

Background and purpose

Quantitative MRI (qMRI) has been explored for detecting tumor changes during radiation therapy (RT) in head and neck squamous cell cancer (HNSCC). Clinical trials show prolonged survival with PD-1 targeted immune checkpoint inhibition. Hypofractionated radiation regimens are being studied to counteract radioresistant clonogen formation. This study aims to use daily qMRI monitoring in these therapies. The objective of this exploratory study was to investigate if qMRI can detect tumor microenvironment changes during hypofractionated RT in a phase I trial of Dose-Escalated Hypofractionated Adaptive Radiotherapy (DEHART).

Materials and methods

Seventeen subjects with advanced HNSCC underwent MR-guided RT with daily qMRI using a 15-fraction regimen to a cumulative dose of 50, 55, or 60 Gy. A 1.5 T MRI-Linac collected daily intravoxel incoherent motion (IVIM), T₁, and T₂ mappings. Median primary tumor ADC, D, D*, f, T₁, and T₂ were calculated, using paraspinal muscle as a control. qMRI parameters were analyzed by treatment condition and length using linear mixed effect models and nonparametric tests.

Results

Significant (p < 0.05) increases in ADC, D, f, and T2 were observed over treatment duration for multiple conditions. Daily monitoring enhanced result significance compared to weekly collection.

Conclusions

Daily qMRI effectively monitors tumor response over short periods and varying treatment conditions. Further studies on radiation and systemic therapy combinations in HNSCC could benefit from daily qMRI data collection.

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引用次数: 0

First dosimetric evaluation of clinical raster-scanned proton, helium and carbon ion treatment plan delivery during simultaneous real-time magnetic resonance imaging

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100722

Sebastian Klüter , Karolin Milewski , Wibke Johnen , Stephan Brons , Jakob Naumann , Stefan Dorsch , Cedric Beyer , Katharina Paul , Kilian A. Dietrich , Tanja Platt , Jürgen Debus , Julia Bauer

This work presents an experimental dosimetric evaluation of raster-scanning particle beam delivery during simultaneous in-beam magnetic resonance (MR) imaging. Using an open MR scanner at an experimental treatment room, radiochromic film comparisons for protons, helium and carbon ions, each with and without simultaneous in-beam cine MR imaging, yielded 2D gamma pass rates ≥ 98.8 % for a 3 % / 1.5 mm criterion, and ≥ 99.9 % for 5 % / 1.5 mm. These results constitute a first experimental confirmation that time varying magnetic fields of MR gradients do not result in clinically relevant additional dose perturbations.

引用次数: 0

Recommendations for reporting and evaluating proton therapy beyond dose and constant relative biological effectiveness 关于报告和评估质子治疗超出剂量和恒定相对生物学有效性的建议。

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2024.100692

Armin Lühr , Dirk Wagenaar , Daniëlle B.P. Eekers , Lars Glimelius , Steven J.M. Habraken , Semi Harrabi , Miranda C.A. Kramer , Ranald I. Mackay , Ana Vaniqui , Alexandru Dasu , Damien C. Weber

Background and purpose

In proton therapy, a relative biological effectiveness (RBE) of 1.1 is used to convert proton dose into an equivalent photon dose. However, RBE varies with tissue type, fraction dose, and beam quality parameters beyond dose such as linear energy transfer (LET) raising concerns about increased local effectiveness and potential toxicity. This work aims to harmonize quantities used for clinical consideration of variable RBE for proton therapy.

Materials and methods

A survey was distributed to proton centres to determine agreement on RBE-related concerns and clinical implementations. A subsequent clinical expert meeting facilitated by the European Particle Therapy Network was held to achieve consensus and to make clinical recommendations how to prescribe and report beyond using dose and constant RBE.

Results

The survey was answered by 17 out of 23 centres contacted (74%). For proton RBE, most concerns existed regarding toxicity in serial organs, while the assumption of an RBE of 1.1 was considered valid for targets. Most physicists intended to consider a physical quantity beyond dose in clinical decision making.

Conclusions

A constant RBE of 1.1 was the consensus for prescribing dose. However, current practice of recording and reporting dose in proton therapy must be complemented: the recommended quantity beyond dose was the dose-averaged LET in water from primary and secondary protons, normalized to unit density. This will facilitate analyses of treatment data on effectiveness beyond dose and between centres. No consensus on a single variable RBE model was found. More clinical training on proton RBE is needed.

背景和目的：在质子治疗中，使用1.1的相对生物有效性（RBE）将质子剂量转换为等效光子剂量。然而，RBE随组织类型、分数剂量和剂量以外的光束质量参数（如线性能量转移（LET））而变化，这引起了人们对局部有效性和潜在毒性增加的担忧。这项工作旨在协调用于质子治疗的可变RBE临床考虑的数量。材料和方法：对质子中心进行调查，以确定对rbe相关问题和临床实施的一致意见。随后在欧洲粒子治疗网络的推动下举行了一次临床专家会议，以达成共识，并就如何处方和报告使用剂量和恒定RBE提出临床建议。结果：在联系的23个中心中，有17个（74%）回答了调查。对于质子RBE，大多数关注存在于一系列器官的毒性，而假设RBE为1.1被认为对靶标有效。大多数物理学家打算在临床决策中考虑剂量以外的物理量。结论：处方剂量的一致RBE值为1.1。然而，目前质子治疗中记录和报告剂量的做法必须加以补充：推荐的剂量以外的量是主质子和次级质子在水中的剂量平均LET，标准化为单位密度。这将有助于分析剂量以外和中心之间的有效性治疗数据。在单变量RBE模型上没有发现共识。需要更多的质子RBE临床培训。

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引用次数: 0

Out-of-field dose assessment for pencil beam scanning proton radiotherapy versus photon radiotherapy for breast cancer in pregnant women

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100721

Menke Weessies, Murillo Bellezzo, Britt J.P. Hupkens, Frank Verhaegen, Gloria Vilches-Freixas

Background and purpose

Cancer affects 1 in 1000–2000 pregnancies annually worldwide, creating challenges in balancing cancer treatment and fetal safety. This study compares out-of-field radiation doses between two treatment modalities: 6MV external photon radiotherapy (XRT) and pencil beam scanning proton-therapy (PBS-PRT) for breast cancer, including imaging, to evaluate PBS-PRT as a potential new treatment option.

Materials and methods

For breast cancer involving lymph node levels 1–4 and the intramammary lymph nodes, treatment plans were created for XRT (with Flattening Filter (FF) and FF-Free (FFF)) and PBS-PRT, prescribing 15 × 2.67 Gy(RBE). Measurements were conducted using an adapted anthropomorphic phantom representing 20- and 30-week pregnancy. Bubble detectors placed in the phantom’s abdomen assessed neutron dose from PBS-PRT, while a Farmer ion chamber was used for imaging and XRT dose.

Results

At 20 weeks, PBS-PRT including imaging delivered 22.4 mSv, reducing dose 3.4-fold versus 6FF XRT and 2.5-fold versus 6FFF XRT. At 30 weeks, the PBS-PRT dose was 25.4 mSv, resulting in 7.6-fold and 6.3-fold reductions compared to 6FF and 6FFF XRT, respectively.

Conclusions

This study presents the first one-by-one comparison between PBS-PRT and different XRT modalities for pregnant breast cancer patients with an adapted anthropomorphic phantom. PBS-PRT measurements showed that the total equivalent dose was below the 100 mSv threshold outlined in AAPM Task Group Report No. 36 for a 30-week pregnancy, even under a worst-case scenario, maintaining treatment goals. These findings support the adoption of PBS-PRT as the preferred approach for treating pregnant breast cancer patients, should radiotherapy be required.

{"title":"Out-of-field dose assessment for pencil beam scanning proton radiotherapy versus photon radiotherapy for breast cancer in pregnant women","authors":"Menke Weessies, Murillo Bellezzo, Britt J.P. Hupkens, Frank Verhaegen, Gloria Vilches-Freixas","doi":"10.1016/j.phro.2025.100721","DOIUrl":"10.1016/j.phro.2025.100721","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Cancer affects 1 in 1000–2000 pregnancies annually worldwide, creating challenges in balancing cancer treatment and fetal safety. This study compares out-of-field radiation doses between two treatment modalities: 6MV external photon radiotherapy (XRT) and pencil beam scanning proton-therapy (PBS-PRT) for breast cancer, including imaging, to evaluate PBS-PRT as a potential new treatment option.</div></div><div><h3>Materials and methods</h3><div>For breast cancer involving lymph node levels 1–4 and the intramammary lymph nodes, treatment plans were created for XRT (with Flattening Filter (FF) and FF-Free (FFF)) and PBS-PRT, prescribing 15 × 2.67 Gy(RBE). Measurements were conducted using an adapted anthropomorphic phantom representing 20- and 30-week pregnancy. Bubble detectors placed in the phantom’s abdomen assessed neutron dose from PBS-PRT, while a Farmer ion chamber was used for imaging and XRT dose.</div></div><div><h3>Results</h3><div>At 20 weeks, PBS-PRT including imaging delivered 22.4 mSv, reducing dose 3.4-fold versus 6FF XRT and 2.5-fold versus 6FFF XRT. At 30 weeks, the PBS-PRT dose was 25.4 mSv, resulting in 7.6-fold and 6.3-fold reductions compared to 6FF and 6FFF XRT, respectively.</div></div><div><h3>Conclusions</h3><div>This study presents the first one-by-one comparison between PBS-PRT and different XRT modalities for pregnant breast cancer patients with an adapted anthropomorphic phantom. PBS-PRT measurements showed that the total equivalent dose was below the 100 mSv threshold outlined in AAPM Task Group Report No. 36 for a 30-week pregnancy, even under a worst-case scenario, maintaining treatment goals. These findings support the adoption of PBS-PRT as the preferred approach for treating pregnant breast cancer patients, should radiotherapy be required.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100721"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimal timing of organs-at-risk-sparing adaptive radiation therapy for head-and-neck cancer under re-planning resource constraints

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100715

Fatemeh Nosrat , Cem Dede , Lucas B. McCullum , Raul Garcia , Abdallah S.R. Mohamed , Jacob G. Scott , James E. Bates , Brigid A. McDonald , Kareem A. Wahid , Mohamed A. Naser , Renjie He , Aysenur Karagoz , Amy C. Moreno , Lisanne V. van Dijk , Kristy K. Brock , Jolien Heukelom , Seyedmohammadhossein Hosseinian , Mehdi Hemmati , Andrew J. Schaefer , Clifton D. Fuller

Background and purpose

Prior work on adaptive organ-at-risk (OAR)-sparing radiation therapy has typically reported outcomes based on fixed-number or fixed-interval re-planning, which represent one-size-fits-all approaches and do not account for the variable progression of individual patients’ toxicities. The purpose of this study was to determine the personalized optimal timing of re-planning in adaptive OAR-sparing radiation therapy, considering limited re-planning resources, for patients with head and neck cancer (HNC).

Materials and methods

A novel Markov decision process (MDP) model was developed to determine optimal timing of re-planning based on the patient’s expected toxicity, characterized by normal tissue complication probability (NTCP), for four toxicities. The MDP parameters were derived from a dataset comprising 52 HNC patients treated between 2007 and 2013. Kernel density estimation was used to smooth the sample distributions. Optimal re-planning strategies were obtained when the permissible number of re-plans throughout the treatment was limited to 1, 2, and 3, respectively.

Results

The MDP (optimal) solution recommended re-planning when the difference between planned and actual NTCPs (ΔNTCP) was greater than or equal to 1%, 2%, 2%, and 4% at treatment fractions 10, 15, 20, and 25, respectively, exhibiting a temporally increasing pattern. The ΔNTCP thresholds remained constant across the number of re-planning allowances (1, 2, and 3).

Conclusion

In limited-resource settings that impeded high-frequency adaptations, ΔNTCP thresholds obtained from an MDP model could derive optimal timing of re-planning to minimize the likelihood of treatment toxicities.

{"title":"Optimal timing of organs-at-risk-sparing adaptive radiation therapy for head-and-neck cancer under re-planning resource constraints","authors":"Fatemeh Nosrat , Cem Dede , Lucas B. McCullum , Raul Garcia , Abdallah S.R. Mohamed , Jacob G. Scott , James E. Bates , Brigid A. McDonald , Kareem A. Wahid , Mohamed A. Naser , Renjie He , Aysenur Karagoz , Amy C. Moreno , Lisanne V. van Dijk , Kristy K. Brock , Jolien Heukelom , Seyedmohammadhossein Hosseinian , Mehdi Hemmati , Andrew J. Schaefer , Clifton D. Fuller","doi":"10.1016/j.phro.2025.100715","DOIUrl":"10.1016/j.phro.2025.100715","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Prior work on adaptive organ-at-risk (OAR)-sparing radiation therapy has typically reported outcomes based on fixed-number or fixed-interval re-planning, which represent one-size-fits-all approaches and do not account for the variable progression of individual patients’ toxicities. The purpose of this study was to determine the personalized optimal timing of re-planning in adaptive OAR-sparing radiation therapy, considering limited re-planning resources, for patients with head and neck cancer (HNC).</div></div><div><h3>Materials and methods</h3><div>A novel Markov decision process (MDP) model was developed to determine optimal timing of re-planning based on the patient’s expected toxicity, characterized by normal tissue complication probability (NTCP), for four toxicities. The MDP parameters were derived from a dataset comprising 52 HNC patients treated between 2007 and 2013. Kernel density estimation was used to smooth the sample distributions. Optimal re-planning strategies were obtained when the permissible number of re-plans throughout the treatment was limited to 1, 2, and 3, respectively.</div></div><div><h3>Results</h3><div>The MDP (optimal) solution recommended re-planning when the difference between planned and actual NTCPs (ΔNTCP) was greater than or equal to 1%, 2%, 2%, and 4% at treatment fractions 10, 15, 20, and 25, respectively, exhibiting a temporally increasing pattern. The ΔNTCP thresholds remained constant across the number of re-planning allowances (1, 2, and 3).</div></div><div><h3>Conclusion</h3><div>In limited-resource settings that impeded high-frequency adaptations, ΔNTCP thresholds obtained from an MDP model could derive optimal timing of re-planning to minimize the likelihood of treatment toxicities.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100715"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143350636","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Critical assessment of knowledge-based models for craniospinal irradiation of paediatric patients

IF 3.4 Q2 ONCOLOGY

Physics and Imaging in Radiation Oncology

Pub Date : 2025-01-01 DOI: 10.1016/j.phro.2025.100703

Paolo Caricato , Francesca Cavagnetto , Silvia Meroni , Salvina Barra , Laura Brambilla , Enrica Bovo , Samuele Cavinato , Alessio Cirone , Flavio Giannelli , Marta Paiusco , Emilia Pecori , Emanuele Pignoli , Margherita Pollara , Giovanni Scarzello , Alessandro Scaggion

Background and purpose

Knowledge-Based Planning (KBP) is increasingly used to standardize and optimize radiotherapy planning. This study aims to develop, refine, and compare multicentric KBP models for craniospinal irradiation (CSI) in pediatric patients.

Materials and methods

A total of 113 CSI treatments from three Italian centers were collected, comprising Computed Tomography scans, target and organ contours, and treatment plans. Treatment techniques included Helical Tomotherapy (HT) and Volumetric Modulated Arc Therapy (VMAT). Three KBP models were developed: a full model (F-model) using data from 87 patients, a reduced model (R-model) based on a subset of the same sample, and a replanned model (RP-model) using KBP re-optimized plans. Models’ quality was evaluated using goodness-of-fit and goodness-of-prediction metrics, and their performance was assessed on a validation set of 26 patients through dose-volume histogram (DVH) comparisons, prediction bias, and variance analysis.

Results

The F-model and R-model exhibited similar quality and predictive ability, reflecting the variability of the original dataset and resulting in broad prediction intervals in low to mid-dose ranges. The RP-model achieved the highest quality, with narrower prediction bands. The RP-model is preferable for standardizing planning across centers, while the F-model is better suited for quality assurance as it captures clinical variability.

Conclusions

KBP models can effectively predict DVHs despite extreme geometric variability. However, models trained on highly variable datasets cannot simultaneously achieve high precision and accuracy. Comparing KBP models is essential for establishing benchmarks to meet specific clinical goals, particularly for complex pediatric CSI treatments.

{"title":"Critical assessment of knowledge-based models for craniospinal irradiation of paediatric patients","authors":"Paolo Caricato , Francesca Cavagnetto , Silvia Meroni , Salvina Barra , Laura Brambilla , Enrica Bovo , Samuele Cavinato , Alessio Cirone , Flavio Giannelli , Marta Paiusco , Emilia Pecori , Emanuele Pignoli , Margherita Pollara , Giovanni Scarzello , Alessandro Scaggion","doi":"10.1016/j.phro.2025.100703","DOIUrl":"10.1016/j.phro.2025.100703","url":null,"abstract":"<div><h3>Background and purpose</h3><div>Knowledge-Based Planning (KBP) is increasingly used to standardize and optimize radiotherapy planning. This study aims to develop, refine, and compare multicentric KBP models for craniospinal irradiation (CSI) in pediatric patients.</div></div><div><h3>Materials and methods</h3><div>A total of 113 CSI treatments from three Italian centers were collected, comprising Computed Tomography scans, target and organ contours, and treatment plans. Treatment techniques included Helical Tomotherapy (HT) and Volumetric Modulated Arc Therapy (VMAT). Three KBP models were developed: a full model (F-model) using data from 87 patients, a reduced model (R-model) based on a subset of the same sample, and a replanned model (RP-model) using KBP re-optimized plans. Models’ quality was evaluated using goodness-of-fit and goodness-of-prediction metrics, and their performance was assessed on a validation set of 26 patients through dose-volume histogram (DVH) comparisons, prediction bias, and variance analysis.</div></div><div><h3>Results</h3><div>The F-model and R-model exhibited similar quality and predictive ability, reflecting the variability of the original dataset and resulting in broad prediction intervals in low to mid-dose ranges. The RP-model achieved the highest quality, with narrower prediction bands. The RP-model is preferable for standardizing planning across centers, while the F-model is better suited for quality assurance as it captures clinical variability.</div></div><div><h3>Conclusions</h3><div>KBP models can effectively predict DVHs despite extreme geometric variability. However, models trained on highly variable datasets cannot simultaneously achieve high precision and accuracy. Comparing KBP models is essential for establishing benchmarks to meet specific clinical goals, particularly for complex pediatric CSI treatments.</div></div>","PeriodicalId":36850,"journal":{"name":"Physics and Imaging in Radiation Oncology","volume":"33 ","pages":"Article 100703"},"PeriodicalIF":3.4,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143130346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0