Radiological Physics and Technology最新文献_第2页

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. 白蛋白-胆红素评分预测肝硬化患者腹部动态增强多探测器计算机断层扫描门静脉期肝实质增强的潜力。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-14 DOI: 10.1007/s12194-025-00895-1

Yasuhiro Inokuchi, Hiromasa Kurosaki

{"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":"https://doi.org/10.1007/s12194-025-00895-1","url":null,"abstract":"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.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-14","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}

引用次数: 0

Initial demonstration of the Scratch-PET concept: an intraoperative PET with a hand-held detector. 划痕PET概念的初步演示：术中带手持检测器的PET。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-12 DOI: 10.1007/s12194-025-00889-z

Taiyo Ishikawa, Yuma Iwao, Go Akamatsu, Sodai Takyu, Hideaki Tashima, Takayuki Okamoto, Taiga Yamaya, Hideaki Haneishi

{"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":"https://doi.org/10.1007/s12194-025-00889-z","url":null,"abstract":"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 mm3) 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 22Na multi-rod phantom and two 22Na 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.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143617559","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}

引用次数: 0

Cone-beam computed tomography (CBCT) image-quality improvement using a denoising diffusion probabilistic model conditioned by pseudo-CBCT of pelvic regions. 锥形束计算机断层扫描（CBCT）图像质量的改进，采用骨盆区域伪CBCT条件下的去噪扩散概率模型。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-04 DOI: 10.1007/s12194-025-00892-4

Masayuki Hattori, Hongbo Chai, Toshitada Hiraka, Koji Suzuki, Tetsuya Yuasa

{"title":"Cone-beam computed tomography (CBCT) image-quality improvement using a denoising diffusion probabilistic model conditioned by pseudo-CBCT of pelvic regions.","authors":"Masayuki Hattori, Hongbo Chai, Toshitada Hiraka, Koji Suzuki, Tetsuya Yuasa","doi":"10.1007/s12194-025-00892-4","DOIUrl":"https://doi.org/10.1007/s12194-025-00892-4","url":null,"abstract":"Cone-beam computed tomography (CBCT) is widely used in radiotherapy to image patient configuration before treatment but its image quality is lower than planning CT due to scattering, motion, and reconstruction methods. This reduces the accuracy of Hounsfield units (HU) and limits its use in adaptive radiation therapy (ART). However, synthetic CT (sCT) generation using deep learning methods for CBCT intensity correction faces challenges due to deformation. To address these issues, we propose enhancing CBCT quality using a conditional denoising diffusion probability model (CDDPM), which is trained on pseudo-CBCT created by adding pseudo-scatter to planning CT. The CDDPM transforms CBCT into high-quality sCT, improving HU accuracy while preserving anatomical configuration. The performance evaluation of the proposed sCT showed a reduction in mean absolute error (MAE) from 81.19 HU for CBCT to 24.89 HU for the sCT. Peak signal-to-noise ratio (PSNR) improved from 31.20 dB for CBCT to 33.81 dB for the sCT. The Dice and Jaccard coefficients between CBCT and sCT for the colon, prostate, and bladder ranged from 0.69 to 0.91. When compared to other deep learning models, the proposed sCT outperformed them in terms of accuracy and anatomical preservation. The dosimetry analysis for prostate cancer revealed a dose error of over 10% with CBCT but nearly 0% with the sCT. Gamma pass rates for the proposed sCT exceeded 90% for all dose criteria, indicating high agreement with CT-based dose distributions. These results show that the proposed sCT improves image quality, dosimetry accuracy, and treatment planning, advancing ART for pelvic cancer.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543461","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}

引用次数: 0

Comparative analysis of radiotherapy modalities and techniques for left breast cancer: dose coverage, setup accuracy, with patient-specific selection criteria for applying deep inspiration breath hold. 左乳腺癌放疗方式和技术的比较分析：剂量覆盖，设置准确性，以及应用深度吸气屏气的患者特异性选择标准。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-04 DOI: 10.1007/s12194-025-00891-5

Masud Parvej, Cristina Cappelletto, Angela Caroli, Lorenzo Vinante, Annalisa Drigo, Paola Chiovati

{"title":"Comparative analysis of radiotherapy modalities and techniques for left breast cancer: dose coverage, setup accuracy, with patient-specific selection criteria for applying deep inspiration breath hold.","authors":"Masud Parvej, Cristina Cappelletto, Angela Caroli, Lorenzo Vinante, Annalisa Drigo, Paola Chiovati","doi":"10.1007/s12194-025-00891-5","DOIUrl":"https://doi.org/10.1007/s12194-025-00891-5","url":null,"abstract":"To compare dosimetric outcomes between Free Breath (FB) and Deep Inspiration Breath Hold (DIBH) across different radiotherapy modalities, establish patient selection criteria for DIBH, and optimizing the setup margin (SM) in left breast cancer treatment. 26 patients with left breast cancer were studied at CRO, Aviano in Italy. FB and DIBH simulations were done using CT with a real-time position management system. 3DCRT and IMRT plans were prepared for both simulations of each patient. The setup margin was measured by Van Herk's formula and compared with residual uncertainties. The dose coverage of PTV and spare OARs were better with DIBH. The distance of more than 1.6 cm between (Left Anterior Descending artery) LAD and PTV was no significantly different for FB and DIBH. The setup margin by Van Herk's formula was calculated as 0.9 cm for DIBH_IMRT. The average duration of DIBH per respiration was 19 ± 4 s. So, holding one breath at least 19 s would be the criteria for choosing a patient to apply DIBH. DIBH enhances PTV dose coverage and OAR sparing in both 3DCRT and IMRT. When the distance between the LAD and PTV exceeds 1.6 cm, the application of DIBH depends on the availability of a LINAC with RPM and the patient's breathholding ability.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143543066","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}

引用次数: 0

Deep learning-based approach for acquisition time reduction in ventilation SPECT in patients after lung transplantation. 基于深度学习的方法缩短肺移植术后患者通气 SPECT 的采集时间

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-01 Epub Date: 2024-10-23 DOI: 10.1007/s12194-024-00853-3

Masahiro Nakashima, Ryohei Fukui, Seiichiro Sugimoto, Toshihiro Iguchi

{"title":"Deep learning-based approach for acquisition time reduction in ventilation SPECT in patients after lung transplantation.","authors":"Masahiro Nakashima, Ryohei Fukui, Seiichiro Sugimoto, Toshihiro Iguchi","doi":"10.1007/s12194-024-00853-3","DOIUrl":"10.1007/s12194-024-00853-3","url":null,"abstract":"We aimed to evaluate the image quality and diagnostic performance of chronic lung allograft dysfunction (CLAD) with lung ventilation single-photon emission computed tomography (SPECT) images acquired briefly using a convolutional neural network (CNN) in patients after lung transplantation and to explore the feasibility of short acquisition times. We retrospectively identified 93 consecutive lung-transplant recipients who underwent ventilation SPECT/computed tomography (CT). We employed a CNN to distinguish the images acquired in full time from those acquired in a short time. The image quality was evaluated using the structural similarity index (SSIM) loss and normalized mean square error (NMSE). The correlation between functional volume/morphological volume (F/M) ratios of full-time SPECT images and predicted SPECT images was evaluated. Differences in the F/M ratio were evaluated using Bland-Altman plots, and the diagnostic performance was compared using the area under the curve (AUC). The learning curve, obtained using MSE, converged within 100 epochs. The NMSE was significantly lower (P < 0.001) and the SSIM was significantly higher (P < 0.001) for the CNN-predicted SPECT images compared to the short-time SPECT images. The F/M ratio of full-time SPECT images and predicted SPECT images showed a significant correlation (r = 0.955, P < 0.0001). The Bland-Altman plot revealed a bias of -7.90% in the F/M ratio. The AUC values were 0.942 for full-time SPECT images, 0.934 for predicted SPECT images and 0.872 for short-time SPECT images. Our findings suggest that a deep-learning-based approach can significantly curtail the acquisition time of ventilation SPECT, while preserving the image quality and diagnostic accuracy for CLAD.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"47-57"},"PeriodicalIF":1.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142510160","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}

引用次数: 0

Development of an image quality evaluation system for bedside chest X-ray images using scatter correction processing. 基于散射校正处理的床边胸部x线图像质量评价系统的开发。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-01 Epub Date: 2025-01-11 DOI: 10.1007/s12194-025-00879-1

Kazuya Mori, Toru Negishi

{"title":"Development of an image quality evaluation system for bedside chest X-ray images using scatter correction processing.","authors":"Kazuya Mori, Toru Negishi","doi":"10.1007/s12194-025-00879-1","DOIUrl":"10.1007/s12194-025-00879-1","url":null,"abstract":"In plain radiography, scattered X-ray correction processing (Virtual Grid: VG) is used to estimate and correct scattered rays in images. We developed an objective evaluation system for bedside chest X-ray images using VG and investigated its usefulness. First, we trained the blind/referenceless image spatial quality evaluator (BRISQUE) on 200 images obtained by portable chest radiography. We then evaluated optimal chest phantom VG images as well as those that deviated from the VG setting conditions using BRISQUE. Furthermore, we conducted a subjective evaluation using the mean opinion score (MOS) and established an objective evaluation system for VG images. Finally, the degree of agreement between the MOS subjectively evaluated by 14 radiological technologists and that determined by the objective evaluation system for 100 clinical images obtained by portable chest radiography was calculated using Cohen's kappa coefficient. The correlation coefficient between the BRISQUE score and MOS for chest phantom images was - 0.96 (p < 0.05). The two scores showed a very high linear correlation, indicating the potential of the BRISQUE score as an alternative to MOS. The Cohen's kappa coefficient for the objective evaluation system using the optimal conversion table was 0.42. Conversely, there was a very high detection rate of 82.86% for poor-quality images. An objective evaluation system for bedside chest X-ray images using VG that uses no-reference image quality evaluation helps provide proper image quality. Furthermore, such a system can be constructed with a small amount of training data, which increases the possibility of introducing it to a variety of facilities.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"249-257"},"PeriodicalIF":1.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142967239","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}

引用次数: 0

Quantification of uncertainties in reference and relative dose measurements, dose calculations, and patient setup in modern external beam radiotherapy. 量化现代体外放射治疗中参考和相对剂量测量、剂量计算和患者设置的不确定性。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-01 Epub Date: 2024-11-14 DOI: 10.1007/s12194-024-00856-0

Naoki Kinoshita, Morihito Shimizu, Kana Motegi, Yusuke Tsuruta, Toru Takakura, Hiroshi Oguchi, Chie Kurokawa

{"title":"Quantification of uncertainties in reference and relative dose measurements, dose calculations, and patient setup in modern external beam radiotherapy.","authors":"Naoki Kinoshita, Morihito Shimizu, Kana Motegi, Yusuke Tsuruta, Toru Takakura, Hiroshi Oguchi, Chie Kurokawa","doi":"10.1007/s12194-024-00856-0","DOIUrl":"10.1007/s12194-024-00856-0","url":null,"abstract":"Uncertainties in the steps of external beam radiotherapy (EBRT) affect patient outcomes. However, few studies have investigated major contributors to these uncertainties. This study investigated factors contributing to reducing uncertainty in delivering a dose to a target volume. The EBRT process was classified into four steps: reference dosimetry, relative dosimetry [percentage depth doses (PDDs) and off-center ratios (OCRs)], dose calculations (PDDs and OCRs in a virtual water phantom), and patient setup using an image-guided radiation therapy system. We evaluated the uncertainties for these steps in conventionally fractionated EBRT for intracranial disease using 4-, 6-, and 10-MV flattened photon beams generated from clinical linear accelerators following the Guide to the Expression of Uncertainty in Measurement and an uncertainty evaluation method with uncorrected deflection. The following were the major contributors to these uncertainties: beam quality conversion factors for reference dosimetry; charge measurements, chamber depth, source-to-surface distance, water evaporation, and field size for relative dosimetry; dose calculation accuracy for the dose calculations; image registration, radiation-imaging isocenter coincidence, variation in radiation isocenter due to gantry and couch rotation, and intrafractional motion for the patient setup. Among the four steps, the relative dosimetry and dose calculation (namely, both penumbral OCRs) steps involved an uncertainty of more than 5% with a coverage factor of 1. In the EBRT process evaluated herein, the uncertainties in the relative dosimetry and dose calculations must be reduced.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"58-77"},"PeriodicalIF":1.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11876197/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142630162","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

Proposal of a hybrid dosimetry method for improving work efficiency in CT dose management. 提出一种提高CT剂量管理工作效率的混合剂量学方法。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-01 Epub Date: 2025-02-07 DOI: 10.1007/s12194-025-00881-7

Tomokazu Shohji, Reika Tomioka, Anna Isaka, Ami Yuzawa, Nobutaka Yanano, Ryota Tsukada, Hideki Kato

{"title":"Proposal of a hybrid dosimetry method for improving work efficiency in CT dose management.","authors":"Tomokazu Shohji, Reika Tomioka, Anna Isaka, Ami Yuzawa, Nobutaka Yanano, Ryota Tsukada, Hideki Kato","doi":"10.1007/s12194-025-00881-7","DOIUrl":"10.1007/s12194-025-00881-7","url":null,"abstract":"In recent years in JAPAN, with the reform of work styles and the expansion of radiologists' duties, there has been a demand for more work improvement. Among them, many regulations surrounding computed tomography (CT) tasks require a large amount of time and manpower. In this study, we propose a hybrid method between leakage X-ray dosimetry and CT dose index (CTDI) measurement using a CTDI phantom used for CTDI measurement and elucidate the usefulness of the hybrid method. The results of the CTDI phantom generated more scattered radiation in the CT room; therefore, the previously used thoracoabdominal phantom could be replaced with the CTDI phantom. The number of exposures can be reduced by a factor of 15, work hours by 20 min, and the number of workers by two when evaluated as an average of four facilities using the hybrid method. The hybrid method enables the determination of the reproducibility of the output X-ray dose during leakage X-ray dosimetry, thereby ensuring the reliability of periodic leakage X-ray dosimetry. The use of the proposed hybrid method is reasonable because it is effective for work improvement, such as reducing work time and the number of workers.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"258-267"},"PeriodicalIF":1.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143371258","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}

引用次数: 0

Effectiveness of the air-gap method for reducing radiation dose in neonate CT examinations. 气隙法降低新生儿 CT 检查辐射剂量的有效性。

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-01 Epub Date: 2024-11-05 DOI: 10.1007/s12194-024-00855-1

Takanori Masuda, Yoshinori Funama, Takeshi Nakaura, Tomoyasu Sato, Takayuki Oku, Atsushi Ono, Kazuo Awai

{"title":"Effectiveness of the air-gap method for reducing radiation dose in neonate CT examinations.","authors":"Takanori Masuda, Yoshinori Funama, Takeshi Nakaura, Tomoyasu Sato, Takayuki Oku, Atsushi Ono, Kazuo Awai","doi":"10.1007/s12194-024-00855-1","DOIUrl":"10.1007/s12194-024-00855-1","url":null,"abstract":"The air-gap method is a technique employed to control dose distribution and radiation scattering in medical imaging. By introducing a layer of air between the radiation source and the object, this method effectively reduces the impact of scattered radiation. The purpose of this study was to investigate the suitability of the air-gap method for radiation dose reduction in pediatric patients during computed tomography (CT) examinations. Only one type of neonate phantom is used with 64 detector-row CT scanner while helical scanning the chest. The distance between the CT table and the subject was 0 mm at the conventional method and 150 mm at the air-gap method. The values of the real-time skin dosimeter on the dorsal surface of the body, and on the left and right mammary glands and image noise are measured and compared for each method. Compared with the conventional method, it was possible to reduce the exposure dose and image noise by approximately 10% and 15%, respectively, using the air-gap method (p < 0.05). The air-gap method was useful for reducing the radiation dose during pediatric CT examinations compared with the conventional method.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"293-299"},"PeriodicalIF":1.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142584691","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}

引用次数: 0

IF 1.7

Radiological Physics and Technology Pub Date : 2025-03-01 Epub Date: 2025-02-05 DOI: 10.1007/s12194-025-00882-6

Asuka Kikuchi, Shoichi Watanuki, Hiroshi Watabe, Manabu Tashiro

{"title":"Age-related sensitivity deterioration evaluation of positron emission tomography utilizing cross-calibration factor measurement data.","authors":"Asuka Kikuchi, Shoichi Watanuki, Hiroshi Watabe, Manabu Tashiro","doi":"10.1007/s12194-025-00882-6","DOIUrl":"10.1007/s12194-025-00882-6","url":null,"abstract":"Age-related deterioration in positron emission tomography (PET) systems can be monitored using cross-calibration scans for scanner calibration. This study aimed to evaluate changes in the sensitivity of a PET system over time using routinely collected cross-calibration factor (CCF) measurement data and NEMA sensitivity measurement data acquired at our facility. We used CCF measurement data acquired over eight years, from 2016 to 2023. The count rates were calculated from raw data. The NEMA sensitivity measurements were also performed in 2017 and 2024 to compare with the sensitivities obtained from the CCF measurements. The PET images were reconstructed using the CCF data. A region of interest (ROI) was placed at the center of the PET images and count rates from the PET images were obtained. The sensitivity changes in the CCF data showed a linear decrease in sensitivity over eight years, with a mean annual reduction rate of approximately 2.0%. A comparison of the NEMA sensitivity measurements indicated a decrease in sensitivity, with a 12% reduction over eight eight years. The sensitivity was higher at the center of the axial field of view than at the edges. The ROI data also showed a linear decrease in sensitivity. This is consistent with the CCF data. Additionally, the coefficient of variation increased towards the edge of the slice. By utilizing the CCF measurement data, we obtained age-related changes in the PET system, suggesting that the PET system used in our facility may experience an annual sensitivity deterioration of approximately 2.0%.","PeriodicalId":46252,"journal":{"name":"Radiological Physics and Technology","volume":" ","pages":"268-274"},"PeriodicalIF":1.7,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11876247/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143190933","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