Factual survey of the clinical use of deformable image registration software for radiotherapy in Japan

Abstract

Deformable image registration (DIR) has recently become commercially available in the field of radiotherapy. However, there was no detailed information regarding the use of DIR software at each medical institution. Thus, in this study, we surveyed the status of the clinical use of DIR software for radiotherapy in Japan. The Japan Society of Medical Physics and the Japanese Society for Radiation Oncology mailing lists were used to announce this survey. The questionnaire was created by investigators working under the research grant of the Japanese Society for Radiation Oncology (2017–2018) and intended for the collection of information regarding the use of DIR in radiotherapy. The survey was completed by 161 institutions in Japan. The survey results showed that dose accumulation was the most frequent purpose for which DIR was used in clinical practice (73%). Various commissioning methods were performed, although they were not standardized. Qualitative evaluation with actual patient images was the most commonly used method (28%), although 30% of the total number of responses (42% of institutions) reported that they do not perform commissioning. We surveyed the current status of clinical use of DIR software for radiotherapy in Japan for the first time. Our results indicated that a certain number of institutions used DIR software for clinical practice, and various commissioning methods were performed, although they were not standardized. Taken together, these findings highlight the need for a technically unified approach for commissioning and quality assurance for the use of DIR software in Japan.

An international survey on the clinical use of rigid and deformable image registration in radiotherapy

“…The imaging data used, particularly primary planning images for plan generation but also diagnostic and treatment imaging, could be a major factor in how centers utilized DIR. This survey data agrees with the Japanese data in 2018 15 which found single modality DIR (CT‐CT) as the most common DIR image modality pair. Lower DIR usage of CT‐CBCT usage could correspond to additional complexities such as image noise and streaking 32,33 for contour propagation, or image truncation 32,34 for synthetic CT generation 35 which may creep into the implementation of adaptive radiotherapy 24,36,37 …”

“…While Physicists may not necessarily be routinely involved in RIR, survey data suggest that they have the highest involvement in DIR of all professions, which is in agreement with the findings of a recent DIR survey in Japan 15 . While Physicists may be only indirectly involved in operations they are directly responsible for assessing the performance the IR algorithms and techniques, and provide clinical guidance on associated actions and tolerances.…”

“…which matched our rate of international value from our International data (INTL 26%, AMS 42%, Asia 33%, EU 0%, ANZ 11%). In 2018, Kadoya et al 15 surveyed Japanese practice and characterized the use of deformed images (56%) and dose accumulation (73%) which was within 10% of International averages from this study (65% and 63% on DIR for MMTP and for deformed dose, respectively);…”

“…4 As a single IR technique (RIR or DIR) may not be robust for all circumstances, 10 there is value in data to help select an appropriate IR technique, and data to help decide on a per-patient IR quality assurance. 4 With image-guided radiotherapy (IGRT) surveys emphasizing the growing importance of imaging, [11][12][13][14] there is also DIR adoption data [14][15][16] that highlights the increase in complex IRs. Commercial solutions and clinical needs are factors driving DIR use despite published limitations and risks, resulting in a need to better understand when, what, who, and how IR are clinically used.…”

Evaluation of Deformable Image Registration and Dose Accumulation Using Histogram Matching Algorithm between kVCT and MVCT with Helical Tomotherapy

“…The DIR between two CT images is an effective tool to perform a more accurate [14]. Although their results were not focused on the pelvic images, the accuracy of the deformation using MIM software was comparable with that of the other commercial DIR software.…”