記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Abstract

Purpose

This study evaluates deep learning (DL) based dose prediction methods in head and neck cancer (HNC) patients using two types of input contours.

Materials and methods

Seventy‐five HNC patients undergoing two‐step volumetric‐modulated arc therapy were included. Dose prediction was performed using the AIVOT prototype (AiRato.Inc, Sendai, Japan), a commercial software with an HD U‐net‐based dose distribution prediction system. Models were developed for the initial plan (46 Gy/23Fr) and boost plan (24 Gy/12Fr), trained with 65 cases and tested with 10 cases. The 8‐channel model used one target (PTV) and seven organs at risk (OARs), while the 10‐channel model added two dummy contours (PTV ring and spinal cord PRV). Predicted and deliverable doses, obtained through dose mimicking on another radiation treatment planning system, were evaluated using dose‐volume indices for PTV and OARs.

Results

For the initial plan, both models achieved approximately 2% prediction accuracy for the target dose and maintained accuracy within 3.2 Gy for OARs. The 10‐channel model outperformed the 8‐channel model for certain dose indices. For the boost plan, both models exhibited prediction accuracies of approximately 2% for the target dose and 1 Gy for OARs. The 10‐channel model showed significantly closer predictions to the ground truth for D50% and Dmean. Deliverable plans based on prediction doses showed little significant difference compared to the ground truth, especially for the boost plan.

Conclusion

DL‐based dose prediction using the AIVOT prototype software in HNC patients yielded promising results. While additional contours may enhance prediction accuracy, their impact on dose mimicking is relatively small.

DOI： 10.1002/acm2.14519

記述言語：日本語   掲載種別：研究論文（学術雑誌）  

DOI： https://doi.org/10.18888/rp.0000002750

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Abstract

Although stereotactic body radiotherapy (SBRT) is a curative treatment option for stage I non‐small cell lung cancer (NSCLC), limited data are available regarding chest wall (CW) toxicities during an extended follow‐up of over 10 years. We report an unusual case of a bone tumor‐like CW mass lesion with pathological rib fractures observed 13 years after SBRT for peripheral lung cancer. Despite the initial suspicion of radiation‐induced sarcoma, a subsequent incisional biopsy revealed no evidence of malignancy, and a definitive diagnosis of osteonecrosis was made. Thus, long‐term observation of over 10 years is required to identify late chronic complications following SBRT.

DOI： 10.1111/1759-7714.15419

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Abstract

Background

Surface‐guided radiotherapy (SGRT) is adopted by several institutions; however, reports on the phantoms used to assess the precision of the SGRT setup are limited.

Purpose

The purpose of this study was to develop a phantom to verify the accuracy of the irradiation position during skin mark‐less SGRT.

Methods

An acrylonitrile butadiene styrene (ABS) plastic cube phantom with a diameter of 150 mm on each side containing a dummy target of 15 mm and two types of body surface‐shaped phantoms (breast/face shape) that could be attached to the cube phantom were fabricated. Films can be inserted on four sides of the cubic phantom (left, right, anterior and posterior), and the center of radiation can be calculated by irradiating the dummy target with orthogonal MV beams. Three types of SGRT using a VOXELAN‐HEV600M (Electronics Research&Development Corporation, Okayama, Japan) were evaluated using this phantom: (i) SGRT_CT—a SGRT set‐up based solely on a computed tomography (CT)‐reference image. (ii) SGRT_CT + CBCT—a method where cone beam computed tomography (CBCT) matching was performed after SGRT_CT. (iii) SGRT_Scan—a resetup technique using a scan reference image obtained after completing the (ii) step.

Results

Both the breast and face phantoms were recognized in the SGRT system without problems. SGRT_Scan ensure precision within 1 mm/1° for breast and face verification, respectively. All SGRT methods showed comparable rotational accuracies with no significant disparities.

Conclusions

The developed phantom was useful for verifying the accuracy of skin mark‐less SGRT position matching. The SGRT_Scan demonstrated the feasibility of achieving skin‐mark less SGRT with high accuracy, with deviations of less than 1 mm. Additional research is necessary to evaluate the suitability of the developed phantoms for use in various facilities and systems. This phantom could be used for postal surveys in the future.

DOI： 10.1002/acm2.14381

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Predicting recurrence following stereotactic body radiotherapy (SBRT) for non-small cell lung cancer provides important information for the feasibility of the individualized radiotherapy and allows to select the appropriate treatment strategy based on the risk of recurrence. In this study, we evaluated the performance of both machine learning models using positron emission tomography (PET) and computed tomography (CT) radiomic features for predicting recurrence after SBRT. METHODS: Planning CT and PET images of 82 non-small cell lung cancer patients who performed SBRT at our hospital were used. First, tumors were delineated on each CT and PET of each patient, and 111 unique radiomic features were extracted, respectively. Next, the 10 features were selected using three different feature selection algorithms, respectively. Recurrence prediction models based on the selected features and four different machine learning algorithms were developed, respectively. Finally, we compared the predictive performance of each model for each recurrence pattern using the mean area under the curve (AUC) calculated following the 0.632+ bootstrap method. RESULTS: The highest performance for local recurrence, regional lymph node metastasis, and distant metastasis were observed in models using Support vector machine with PET features (mean AUC = 0.646), Naive Bayes with PET features (mean AUC = 0.611), and Support vector machine with CT features (mean AUC = 0.645), respectively. CONCLUSIONS: We comprehensively evaluated the performance of prediction model developed for recurrence following SBRT. The model in this study would provide information to predict the recurrence pattern and assist in making treatment strategies.

DOI： 10.1002/acm2.14322

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：SAGE Publications  

Background

CyberKnife treatment for central lung tumors and mediastinal tumors can be difficult to perform with marker less.

Purpose

We aimed to evaluate a novel tracheobronchial-based method (ie, tracheobronchial tracking) for the purpose of minimally invasive CyberKnife treatment for central lung and mediastinal tumors.

Methods

Five verification plans were created using an in-house phantom. Each plan included five irradiation sessions. The reference plan irradiated and tracked the simulated tumor (using the target tracking volume, TTV). Trachea plans tracked the simulated tracheo-bronchus and irradiated the simulated tumor and included two types of subplans: correlated plans in which the displacement of the simulated tracheobronchial and the simulated tumor were correlated, and non-correlated plans in which these factors were not correlated. Moreover, 15 mm and 25 mm TTVs were evaluated for each plan. The sin waveform and the patient's respiratory waveform were prepared as the respiratory model. Evaluations were performed by calculating the dose difference between the radiophotoluminescent glass dosimeter (RPLD)-generated mean dose values (generated by the treatment planning system, TPS) and the actual absorbed RPLD dose. Statistical analyses were performed to evaluate findings for each plan. Correlation and prediction errors were calculated for each axis of each plan using log files to evaluate tracking accuracy.

Results

Dose differences were statistically significant only in comparisons with the non-correlated plan. When evaluated using the sin waveform, the mean values for correlation and prediction errors in each axis and for all plans were less than 0.6 mm and 0.1 mm, respectively. In the same manner, they were less than 1.1 mm and 0.2 mm when evaluated using the patient's respiratory waveform.

Conclusion

Our newly-developed tracheobronchial tracking method would be useful in facilitating minimally invasive CyberKnife treatment in certain cases of central lung and mediastinal tumors.

DOI： 10.1177/15330338241232557

その他リンク： http://journals.sagepub.com/doi/full-xml/10.1177/15330338241232557

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jrr/rrad085

記述言語：英語   掲載種別：研究論文（学術雑誌）  

PURPOSE: Lung tumor tracking during stereotactic radiotherapy with the CyberKnife can misrecognize tumor location under conditions where similar patterns exist in the search area. This study aimed to develop a technique for bone signal suppression during kV-x-ray imaging. METHODS: Paired CT images were created with or without bony structures using a 4D extended cardiac-torso phantom (XCAT phantom) in 56 cases. Subsequently, 3020 2D x-ray images were generated. Images with bone were input into cycle-consistent adversarial network (CycleGAN) and the bone suppressed images on the XCAT phantom (BSIphantom ) were created. They were then compared to images without bone using the structural similarity index measure (SSIM) and peak signal-to-noise ratio (PSNR). Next, 1000 non-simulated treatment images from real cases were input into the training model, and bone-suppressed images of the patient (BSIpatient ) were created. Zero means normalized cross correlation (ZNCC) by template matching between each of the actual treatment images and BSIpatient were calculated. RESULTS: BSIphantom values were compared to their paired images without bone of the XCAT phantom test data; SSIM and PSNR were 0.90 ± 0.06 and 24.54 ± 4.48, respectively. It was visually confirmed that only bone was selectively suppressed without significantly affecting tumor visualization. The ZNCC values of the actual treatment images and BSIpatient were 0.763 ± 0.136 and 0.773 ± 0.143, respectively. The BSIpatient showed improved recognition accuracy over the actual treatment images. CONCLUSIONS: The proposed bone suppression imaging technique based on CycleGAN improves image recognition, making it possible to achieve highly accurate motion tracking irradiation.

DOI： 10.1002/acm2.14212

PubMed

担当区分：筆頭著者   記述言語：日本語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Wiley  

Abstract

Background

The purpose of this study was to compare the dosimetric characteristics of five different treatment planning techniques for locally advanced non‐small cell lung cancer (LA‐NSCLC) with sequential plan changes.

Methods

A total of 13 stage III NSCLC patients were enrolled in this study. These patients had both computed tomography (CT) images for initial and boost treatment plans. The latter CT images were taken if tumor shrinkage was observed after 2 weeks of treatment. The prescription dose was 60 Gy/30 Fr (initial: 40 Gy/20 Fr, and boost: 20 Gy/10 Fr). Five techniques (forward‐planed 3‐dimensional conformal radiotherapy [F‐3DCRT] on both CT images, inverse‐planned 3DCRT [I‐3DCRT] on both CT images, volumetric modulated arc therapy [VMAT] on both CT images, F‐3DCRT on initial CT plus VMAT on boost CT [bVMAT], and hybrid of fixed intensity‐modulated radiotherapy [IMRT] beams and VMAT beams on both CT images [hybrid]) were recalculated for all patients. The accumulated doses between initial and boost plans were compared among all treatment techniques.

Results

The conformity indexes (CI) of the planning target volume (PTV) of the five planning techniques were 0.34 ± 0.10, 0.57 ± 0.10, 0.86 ± 0.08, 0.61 ± 0.12, and 0.83 ± 0.11 for F‐3DCRT, I‐3DCRT, VMAT, bVMAT, and hybrid, respectively. In the same manner, lung volumes receiving >20 Gy (V_20Gy) were 21.05 ± 10.56%, 20.86 ± 6.45, 19.50 ± 7.38%, 19.98 ± 10.04%, and 17.74 ± 7.86%. There was significant improvement about CI and V_20Gy for hybrid compared with F‐3DCRT (p < 0.05).

Conclusion

The IMRT/VMAT hybrid technique for LA‐NSCLC patients improved target CI and reduced lung doses. Furthermore, if IMRT was not available initially, starting with 3DCRT might be beneficial as demonstrated in the bVMAT procedure of this study.

DOI： 10.1111/1759-7714.15137

記述言語：英語   掲載種別：研究論文（学術雑誌）  

To report the long-term quality assurance (QA) experience of an on-rail computed tomography (CT) system for image-guided radiotherapy using an in-house phantom. An on-rail CT system combining the Elekta Synergy and Canon Aquilion LB was used. The treatment couch was shared by the linear accelerators and CT, and the couch was rotated by 180° when using the on-rail-CT system to ensure that the CT direction was toward the head. All QA analyses were performed by radiation technologists on CBCT or on-rail CT images of the in-house phantom. The CBCT center accuracy from the linac laser, couch rotational accuracy (CBCT center vs. on-rail CT center), horizontal accuracy by CT gantry shift, and remote couch shift accuracy were evaluated. This study reported the QA status of the system during the period 2014-2021. The absolute mean accuracy of couch rotation was 0.4 ± 0.28 mm, 0.44 ± 0.36 mm, and 0.37 ± 0.27 mm in the SI, RL, and AP directions, respectively. Horizontal and remote movement accuracies of the treatment couch were also within 0.5 mm of the absolute mean value. A decrease in the accuracy of couch rotation was also observed due to aging deterioration of related parts caused by the frequent use of couch rotation. The three-dimensional accuracy of on-rail CT systems derived mainly from treatment couches can be maintained within 0.5 mm with appropriate accuracy assurance for at least > 8 years.

DOI： 10.1007/s12194-023-00718-1

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1002/acm2.13971

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：メディカルアイ  

記述言語：日本語   掲載種別：研究論文（学術雑誌）   出版者・発行元：メディカルアイ  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1093/jrr/rrab078

PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Springer Science and Business Media LLC  

Radiotherapy for esophageal cancer entails high-dose irradiation of the myocardium owing to its close anatomical proximity to the esophagus. This study aimed to evaluate the dosimetric impact of functional avoidance planning for the myocardium with volumetric-modulated arc therapy (VMAT) in patients with esophageal cancer and determine the feasibility of functional planning. Ten patients with early stage esophageal cancer were included in this study. The prescribed dose was 60 Gy administered in 30 fractions. An experienced physician contoured the left ventricle (LV) of the myocardium. For each patient, an anatomical plan (non-LV-sparing plan) and a functional plan (LV-sparing plan) were created using the VMAT. In the functional plan, the mean percentage of LV volume receiving a dose of ≥ 30 and ≥ 40 Gy was 6.0% ± 6.7% and 2.4% ± 2.7%, respectively, whereas in the anatomical plan, they were 11.7% ± 13.1% and 4.9% ± 6.5%, respectively. There were no significant differences with respect to the dose to the hottest 1 cm3 of the planning target volume (PTV) and the minimum dose of the gross tumor volume and the dosimetric parameters of other normal tissues between the anatomical and functional plans. We compared the anatomical and functional plans of patients with esophageal cancer undergoing VMAT. Our results demonstrated that the functional plan reduced the dose to the LV with no significant differences in the organs at risk and PTV, indicating that avoidance planning can be safely performed when administering VMAT in patients with esophageal cancer.

DOI： 10.1007/s12194-021-00623-5

PubMed

その他リンク： https://link.springer.com/article/10.1007/s12194-021-00623-5/fulltext.html

記述言語：英語  

記述言語：英語  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：日本語   出版者・発行元：公益社団法人 日本医学物理学会  

DOI： 10.11323/jjmp.40.3_109

その他リンク： https://doi.org/10.11323/jjmp.40.3_109

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

記述言語：英語   掲載種別：研究論文（学術雑誌）  

担当区分：筆頭著者   記述言語：英語   掲載種別：（MISC）研究発表要旨（国際会議）  

DOI： 10.1002/mp.13589

記述言語：日本語   出版者・発行元：(公社)日本放射線技術学会  

開催年月日： 2024年9月 - 2024年10月

記述言語：英語   会議種別：ポスター発表  

開催地：Washington DC   国名：アメリカ合衆国  

開催年月日： 2024年6月

記述言語：日本語   会議種別：口頭（一般）  

開催地：パシフィコ横浜ノース   国名：日本国  

開催年月日： 2024年5月

記述言語：日本語   会議種別：口頭（一般）  

国名：日本国  

開催年月日： 2024年2月

記述言語：日本語   会議種別：口頭（招待・特別）  

開催地：ZoomによるWebセミナー   国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：その他  

開催地：Web配信   国名：日本国  

開催年月日： 2023年12月

記述言語：日本語   会議種別：口頭（一般）  

開催地：有明セントラルタワーホール＆カンファレンス   国名：日本国  

開催年月日： 2023年11月 - 2023年12月

記述言語：日本語   会議種別：ポスター発表  

開催地：パシフィコ横浜ノース   国名：日本国  

開催年月日： 2023年11月 - 2023年12月

記述言語：日本語   会議種別：口頭（一般）  

開催地：パシフィコ横浜ノース   国名：日本国  

開催年月日： 2023年7月

記述言語：日本語   会議種別：口頭（一般）  

開催地：山梨大学医学部　シミックプラザ　及び　Web配信.   国名：日本国  

開催年月日： 2023年4月

記述言語：日本語   会議種別：口頭（一般）  

開催地：パシフィコ横浜   国名：日本国  

開催年月日： 2023年3月

記述言語：日本語   会議種別：その他  

開催地：オンライン開催   国名：日本国  

開催年月日： 2022年11月

記述言語：日本語   会議種別：口頭（一般）  

開催地：リーガロイヤルホテル広島・NTTクレドホール・広島グリーンアリーナ  

記述言語：日本語   会議種別：口頭（一般）  

開催地：リーガロイヤルホテル広島・NTTクレドホール・広島グリーンアリーナ  

開催年月日： 2022年8月

記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

記述言語：日本語   会議種別：公開講演，セミナー，チュートリアル，講習，講義等  

開催年月日： 2022年7月

記述言語：日本語   会議種別：口頭（一般）  

開催地：オンライン講演会/ベルクラシック甲府　２階「コンチェルト」  

記述言語：日本語   会議種別：口頭（一般）  

開催地：オンライン講演会/ベルクラシック甲府 ２階「コンチェルト」  

開催年月日： 2019年11月

記述言語：日本語   会議種別：口頭（一般）  

記述言語：日本語   会議種別：口頭（一般）  

開催年月日： 2019年11月

記述言語：日本語   会議種別：口頭（一般）  

記述言語：日本語   会議種別：口頭（一般）  

開催年月日： 2019年10月

記述言語：英語   会議種別：口頭（一般）  

記述言語：英語   会議種別：口頭（一般）  

開催年月日： 2019年7月

記述言語：英語   会議種別：ポスター発表  

記述言語：英語   会議種別：ポスター発表  

開催年月日： 2019年4月

記述言語：英語   会議種別：口頭（一般）  

記述言語：英語   会議種別：口頭（一般）  

開催年月日： 2018年11月

記述言語：英語   会議種別：口頭（一般）  

記述言語：英語   会議種別：口頭（一般）  

開催年月日： 2018年10月

記述言語：日本語   会議種別：口頭（一般）  

記述言語：日本語   会議種別：口頭（一般）  

開催年月日： 2018年7月

記述言語：英語   会議種別：口頭（一般）  

記述言語：英語   会議種別：口頭（一般）