{"title":"Impact of a novel respiratory motion reduction block for myocardial perfusion SPECT image quality: a phantom study.","authors":"Hajime Ichikawa, Toyohiro Kato, Takayuki Shibutani, Mitsuaki Terabe, Hideki Shimada","doi":"10.1007/s12194-025-00887-1","DOIUrl":"10.1007/s12194-025-00887-1","url":null,"abstract":"<p><p>Patient motion, particularly due to respiration, often introduces image distortions that compromise diagnostic accuracy in myocardial perfusion single-photon emission computed tomography (SPECT). To address this issue, we developed a novel respiratory motion reduction block (RRB) designed to minimize the respiratory motion of the heart. This study aims to evaluate the impact of the cardiac-centered with RRB (CC<sub>RRB</sub>) orbit, achieved using the RRB, on myocardial perfusion SPECT image quality. SPECT acquisition of a cardiac phantom was performed at the circular, neighboring elliptical (NE), and CC<sub>RRB</sub> orbits. The CC<sub>RRB</sub> orbit was achieved with RRB placed in front of the phantom based on the NE orbit. Count profile curves of the lesion and uniform slice images were obtained from the circumferential profile. Lesion contrast, normal accumulation uniformity, and count distortion were calculated from the circumferential profiles. Full width at half maximum (FWHM) was measured in the lateral, anterior, septal, and inferior walls of the myocardium, and both the mean and standard deviation (SD) were calculated. The lesion contrast was the highest in the NE orbit, slightly lower in the CC<sub>RRB</sub> orbit, and remarkably lower in the circular orbit than in the NE orbit. The uniformity and count distortion were superior for the CC<sub>RRB</sub> orbits. The SD of FWHM was greater in the circular and NE orbits. The CC<sub>RRB</sub> orbit effectively improves uniformity in SPECT imaging, preserving lesion contrast and spatial resolution. The CC<sub>RRB</sub> orbit provides a practical, accessible approach for enhancing image quality in clinical settings.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"376-383"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143450617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Effectiveness of radiation protection educational material during angiography using visualization of scattered radiation by augmented reality technique.","authors":"Koki Noguchi, Toshioh Fujibuchi, Donghee Han","doi":"10.1007/s12194-025-00899-x","DOIUrl":"10.1007/s12194-025-00899-x","url":null,"abstract":"<p><p>In medical settings, radiation exposure among radiation workers is a significant concern, and understanding radiation protection is crucial. We developed and evaluated radiation protection educational materials using an augmented reality application for visualizing scatter radiation. The evaluation included a true/false quiz, a questionnaire based on the ARCS (Attention, Relevance, Confidence, and Satisfaction) model, and open-ended responses. The correct response rates for the true/false quiz were 65.5% and 72.4% for two questions regarding the effect of C-arm angle changes on scatter radiation distribution. The correct response rate for all other questions was 100%. Understanding how changes in C-arm angles specifically affect angiographic procedures proved more challenging than other topics. The ARCS model evaluation of learning motivation revealed average scores of 4.15 for Attention, 3.91 for Relevance, 3.93 for Confidence, and 4.28 for Satisfaction in the scale 5.00.These results suggest that the developed materials are effective in enhancing motivation. However, open-ended responses identified areas for improvement in the application's usability, particularly regarding ease of operation. While the materials successfully enhance motivation, further refinements are needed to address the variation in correct response rates across different scenarios and the usability challenges of the application.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"484-495"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143664868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Risk factors for motion artifacts in fast spin-echo T2-weighted imaging of the prostate magnetic resonance imaging: a retrospective study.","authors":"Takuya Kobata, Tatsuya Yamasaki, Hiroki Katayama, Masatoshi Morimoto, Yukito Maeda, Takashi Norikane, Yuka Yamamoto, Yoshihiro Nishiyama","doi":"10.1007/s12194-025-00897-z","DOIUrl":"10.1007/s12194-025-00897-z","url":null,"abstract":"<p><p>Prostate cancer diagnosis using fast spin-echo (FSE) T2-weight imaging (T2WI) suffers from motion artifacts (T2-MA). We aimed to investigate the risk factors associated with T2-MA. We retrospectively analyzed the basic patient information and localizer images of 168 patients who underwent prostate magnetic resonance imaging at our institution between April 2019 and December 2021. FSE T2WI image quality was classified into Poor, Acceptable, and Excellent groups based on T2-MA severity. Between-group differences were analyzed using the Kruskal-Wallis test, and multinomial logistic regression was used to calculate adjusted odds ratios (ORs) for T2-MA. The bladder area of the Acceptable group was significantly larger than that of the Poor group (P = 0.010). The rectal area was significantly larger in the Poor group than in the Excellent group (P = 0.013). Larger rectal and bladder areas in the localizer image were significant risk factors for severe (OR: 1.136) and mild (OR: 1.032) T2-MA, respectively.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"582-588"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143674738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Predictive models of severe disease in patients with COVID-19 pneumonia at an early stage on CT images using topological properties.","authors":"Takahiro Iwasaki, Hidetaka Arimura, Shohei Inui, Takumi Kodama, Yun Hao Cui, Kenta Ninomiya, Hideyuki Iwanaga, Toshihiro Hayashi, Osamu Abe","doi":"10.1007/s12194-025-00906-1","DOIUrl":"10.1007/s12194-025-00906-1","url":null,"abstract":"<p><p>Prediction of severe disease (SVD) in patients with coronavirus disease (COVID-19) pneumonia at an early stage could allow for more appropriate triage and improve patient prognosis. Moreover, the visualization of the topological properties of COVID-19 pneumonia could help clinical physicians describe the reasons for their decisions. We aimed to construct predictive models of SVD in patients with COVID-19 pneumonia at an early stage on computed tomography (CT) images using SVD-specific features that can be visualized on accumulated Betti number (BN) maps. BN maps (b0 and b1 maps) were generated by calculating the BNs within a shifting kernel in a manner similar to a convolution. Accumulated BN maps were constructed by summing BN maps (b0 and b1 maps) derived from a range of multiple-threshold values. Topological features were computed as intrinsic topological properties of COVID-19 pneumonia from the accumulated BN maps. Predictive models of SVD were constructed with two feature selection methods and three machine learning models using nested fivefold cross-validation. The proposed model achieved an area under the receiver-operating characteristic curve of 0.854 and a sensitivity of 0.908 in a test fold. These results suggested that topological image features could characterize COVID-19 pneumonia at an early stage as SVD.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"534-546"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12103364/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144040515","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}
{"title":"Non-lead flexible composite shields efficiency in decreasing dose in chest CT scan imaging.","authors":"Mahdi Mansoori Kia, Soheila Refahi, Parinaz Mehnati, Reza Malekzadeh, Aarefeh Jafarzadeh Kohneloo","doi":"10.1007/s12194-025-00885-3","DOIUrl":"10.1007/s12194-025-00885-3","url":null,"abstract":"<p><p>Lead-based radiation shielding used usually in radiology departments is being replaced by non-lead shields due to concerns over toxicity, high weight, and the impossibility of applying it in the imaging field. New studies refer to the use of nanomaterials and lightweight polymer-based composites as an alternative that can solve the problems caused by lead shields. The study aims to develop a flexible composite shield for CT scan imaging and examine its effectiveness in reducing radiation exposure. This study involved the construction of 1 mm thick composite shields used in chest CT scan imaging. The first type consisted of 10% bismuth oxide, the second type consisted of 10% tungsten, the third type consisted of 5% bismuth oxide and 5% tungsten, and 90% of the rest of the structure of all shields was silicone. This study examined the morphological test, tensile strength test, attenuation efficiency, and image quality assessment of these shields. The radiation transmission coefficient for 10% bismuth, 10% tungsten and 5% bismuth-5%tungsten shields was obtained as 0.86, 0.80, and 0.83, respectively. Also, the noise increasing percentage for mentioned shields were 6, 4, and 6%, respectively, compared to the case without a shield. The study found that the 10% tungsten-90% silicone shield is the most effective in reducing radiation exposure due to its K-edge and attenuation coefficients. According to the noise assessment, using these shields does not significantly affect the quality of images.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"358-365"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143494043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Comparison of image quality evaluation methods for magnetic resonance imaging using compressed sensing-sensitivity encoding (CS-SENSE).","authors":"Norikazu Koori, Shohei Yamamoto, Hiroki Kamekawa, Hiraku Fuse, Masato Takahashi, Shin Miyakawa, Kota Sasaki, Reina Naruse, Kenji Yasue, Hiroki Nosaka, Yasuo Takatsu, Kosaku Saotome, Kazuma Kurata","doi":"10.1007/s12194-025-00911-4","DOIUrl":"10.1007/s12194-025-00911-4","url":null,"abstract":"<p><p>This study aimed to compare the relationship between the quantitative values and visual score of acquired images using the CS-SENSE method. T<sub>1</sub>-weighted image (T<sub>1</sub>WI) and T<sub>2</sub>-weighted image (T<sub>2</sub>WI) were acquired using a phantom created by a 3D printer. Each quantitative values (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], structural similarity [SSIM], and scale-invariant feature transform [SIFT]) and visual evaluation score (VES) were calculated by the acquired images. The correlation coefficients among the calculating quantitative values and VES were calculated. The difference in methods for evaluating the image quality of T<sub>1</sub>WI and T<sub>2</sub>WI images using CS-SENSE was clarified. Variations in image quality, as reflected by VES in T<sub>1</sub>WI and T<sub>2</sub>WI images obtained via the CS-SENSE method, can be quantitatively assessed. Specifically, CNR is effective for evaluating changes in T<sub>1</sub>WI, while SNR, CNR, and SIFT are suitable for assessing variations in T<sub>2</sub>WI.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"597-605"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144003836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Initial demonstration of the Scratch-PET concept: an intraoperative PET with a hand-held detector.","authors":"Taiyo Ishikawa, Yuma Iwao, Go Akamatsu, Sodai Takyu, Hideaki Tashima, Takayuki Okamoto, Taiga Yamaya, Hideaki Haneishi","doi":"10.1007/s12194-025-00889-z","DOIUrl":"10.1007/s12194-025-00889-z","url":null,"abstract":"<p><p>Positron emission tomography (PET) is a valuable tool for diagnosing malignant tumors. Intraoperative PET imaging is expected to allow the more accurate localization of tumors that need resections. However, conventional devices feature a large detector ring that obstructs surgical procedures, preventing their intraoperative application. This paper proposes a new PET device, Scratch-PET, for image-guided tumor resection. The key feature of Scratch-PET is its use of a hand-held detector to scan the surgical field, ensuring open space for surgery while measuring annihilation radiation with a fixed detector array placed below the patient. We developed a prototype device using two detectors: the hand-held detector and a fixed detector, to demonstrate the feasibility of the proposed concept. Both detectors consisted of 16 × 16 arrays of lutetium yttrium orthosilicates (3 × 3 × 15 mm<sup>3</sup>) coupled one-to-one with 16 × 16 silicon photomultiplier arrays. The position and orientation of the hand-held detector are tracked using an optical tracking sensor that detects attached markers. We measured a <sup>22</sup>Na multi-rod phantom and two <sup>22</sup>Na point sources separately for 180 s while moving the hand-held detector. The rod diameters were 6.0, 5.0, 4.0, 3.0, 2.2, and 1.6 mm. Each point source was placed at the field-of-view center and 35 mm off-center which was outside the sensitive area when the hand-held detector was positioned facing the fixed detector. The 2.2 mm rods were partially resolved, and both point sources were successfully visualized. The potential of the proposed device to visualize small tumors was validated.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"407-416"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12103487/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143617559","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}
{"title":"Potential of the albumin-bilirubin score to predict the hepatic parenchymal contrast enhancement in the portal phase of abdominal dynamic contrast-enhanced multi-detector computed tomography in patients with liver cirrhosis.","authors":"Yasuhiro Inokuchi, Hiromasa Kurosaki","doi":"10.1007/s12194-025-00895-1","DOIUrl":"10.1007/s12194-025-00895-1","url":null,"abstract":"<p><p>The albumin-bilirubin (ALBI) score was recently used to predict hepatic reserve. This score is a continuous variable that is used to determine cutoff values and is easily calculated from albumin and bilirubin levels alone. Thus, we aimed to investigate whether the ALBI score could predict a decreased hepatic parenchymal contrast enhancement (HPCE) during the portal phase of dynamic multi-detector computed tomography in patients with liver cirrhosis (LC). We retrospectively investigated Pearson's correlation between the HPCE and ALBI score in 26 patients diagnosed with liver cirrhosis. We classified the patients into those with HPCE < 50 HU or ≥ 50 HU and investigated whether the ALBI score differed significantly between these two groups. Furthermore, we used receiver operating characteristic curve analysis to determine the appropriate cutoff value of ALBI score for predicting LC patients with HPCE < 50 HU and ascertained the related area under the curve (AUC), sensitivity, and specificity. The HPCE and ALBI score correlated significantly (r = -0.496, P = 0.0098). The ALBI score differed significantly between groups with HPCE < 50 HU and ≥ 50 HU (P = 0.0012). The cutoff value of the ALBI score for detecting LC patients with HPCE < 50 HU was -2.14, with an AUC, sensitivity, and specificity of 0.906, 83%, and 87%, respectively. In conclusion, the ALBI score is related to the HPCE during the portal phase in LC patients, and a cutoff value of ALBI score of -2.14 can predict the HPCE < 50 HU in LC patients.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"451-456"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143634868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impact of iso-dose levels on pre-treatment quality assurance in volumetric modulated arc therapy.","authors":"Sumanta Manna, Sanjib Gayen, Sonal Varshney","doi":"10.1007/s12194-025-00902-5","DOIUrl":"10.1007/s12194-025-00902-5","url":null,"abstract":"<p><p>The current standard of modern radiotherapy pre-treatment evaluation of dose distributions measured using gamma pass percentage is the predominant metric for Patient-Specific Quality Assurance (PSQA). The aim of the study was to analyze the impact of the different dose levels for three different gamma criteria in various anatomical sites. Retrospectively selected 120 VMAT plans of the brain, head and neck, thorax, and pelvic sites were considered for this study. Quality assurance plans were created and measurements were done using PTW Octavius 4D phantom. Three different gamma criteria were used to evaluate different dose levels' volume gamma passing rates. The maximum gamma passing rate for all dose levels except 100% with a 3%/3 mm criterion was observed for the pelvis site. A significant variation in dose levels was observed with the 3%/2 mm gamma criteria for head and neck sites, particularly above the 85% dose level compared to other anatomical sites. Using 2%/2 mm gamma criteria, there was a rapid fall in the gamma passing rate and all the dose levels showed a significant variation among different sites. This study demonstrated significant variations in gamma passing rates across anatomical sites and dose levels, emphasizing the importance of tailored QA protocols. The findings underscore the need for site-specific action limits and highlight the sensitivity of stricter gamma criteria for detecting errors in complex treatment plans.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"505-513"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143765298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Radiation dose at the eye lens of patients undergoing radiation therapy for head and neck cancer.","authors":"Panatsada Awikunprasert, Jumneanphan Rueansri, Kittipong Suangamiam, Chaknarin Koedsawat, Surasak Tamon, Nattakarn Kittiva, Tanapol Dachviriyakij","doi":"10.1007/s12194-025-00886-2","DOIUrl":"10.1007/s12194-025-00886-2","url":null,"abstract":"<p><p>Linear accelerator irradiation, the most common treatment for head and neck cancer, requires accurate prediction of lens radiation doses to ensure patient safety. The eye lens, being highly radiosensitive and vulnerable to scattered radiation, is at increased risk of developing cataracts. This study compared radiation doses calculated by the treatment planning system (TPS) with those measured in vivo using optically stimulated luminescence (OSL) dosimeters placed on the eyes of 18 patients undergoing radiotherapy for various head and neck cancers. Bland-Altman analysis was used to assess the agreement between the two methods. The results showed that TPS-calculated doses were significantly higher than OSL-measured doses, with TPS values averaging twice as high. However, in three cases, the measured OSL doses exceeded the TPS predictions. The Bland-Altman plot revealed poor agreement between the two methods. The mean doses to the left and right eye lenses were 182 cGy and 170 cGy, respectively, with the highest recorded doses being 492 cGy for the left eye and 513 cGy for the right eye. Patients with nasopharyngeal cancer received the highest doses, and four patients had doses in the 3-5 Gy range, increasing their risk of cataracts. These findings emphasize the importance of validating TPS accuracy in clinical practice to ensure optimal patient care. Further research is necessary to explore the discrepancies between dose measurements and enhance TPS precision, improving clinical outcomes and patient safety in radiation therapy.</p>","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"366-375"},"PeriodicalIF":1.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143374629","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}