Evaluation of the radiation dose in micro‐CT with optimization of the scan protocol

Willekens, Inneke; Buls, Nico; Lahoutte, Tony; Baeyens, Luc; Vanhove, Christian; Caveliers, Vicky; Deklerck, Rudi; Bossuyt, Axel; Mey, Johan De

doi:10.1002/cmmi.394

Cited by 74 publications

(81 citation statements)

References 23 publications

(22 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Moreover, significant doses (well into the centigray range) were obtained when the standard settings, that is, as set by the manufacturers, were used (Table 1). Fortunately, the average absorbed dose could be lowered at least 7-fold by altering the preset parameters as described-a dose that was comparable to earlier published work (7). Moreover, the radial dose distribution illustrated that the x-rays are significantly attenuated as they traverse the body of the mouse (or phantom), typically leading to a relatively higher dose to the skin than to the body or organs situated more centrally.…”

Section: Discussionsupporting

confidence: 69%

Micro-CT for Anatomic Referencing in PET and SPECT: Radiation Dose, Biologic Damage, and Image Quality

Kersemans¹,

Thompson²,

Cornelissen³

et al. 2011

J Nucl Med

Self Cite

View full text Add to dashboard Cite

CT is widely used for anatomic referencing of PET and SPECT images of small animals but requires sufficiently high radiation doses capable of causing significant DNA damage. Therefore, we described the relationship between radiation dose, biologic damage, and image quality to determine whether CT can be used without significantly compromising radiotherapy and tumor development studies. Methods: The CT dose index generated by the nanoSPECT/CT system was compared with measurements using EBT2 gafchromic film. The effects of micro-CT were evaluated in 2 mouse strains that differ in sensitivity to radiation. gH2AX foci analysis to determine leukocyte, liver, and jejunum DNA damage and hematoxylin and eosin staining to investigate macroscopic jejunum damage were performed. Signal-to-noise ratio, contrast-to-noise ratio, and scanner linearity were determined to assess image quality. Results: For the standard settings, that is, as set by the manufacturers, EBT2 gafchromic film dosimetry showed that the nanoSPECT/ CT system underestimated the absorbed dose. Moreover, significant doses were obtained, resulting in a significant increase in gH2AX formation in leukocytes, liver, and jejunum 40 min after CT, using preset parameters when compared with nonimaged controls. The jejenum response was more pronounced for the more radiosensitive strain. In contrast to leukocytes, the liver and jejunum still showed evidence of DNA damage 3 d after CT. Contrast-to-noise ratio, signal-to-noise ratio, and scanner linearity were sufficient to allow for anatomic referencing for both imaging protocols tested. Conclusion: Anatomic reference images can be produced with no observable DNA damage or compromising image quality using low radiographic voltage, flux, and duration.

show abstract

Section: Discussionsupporting

confidence: 69%

Micro-CT for Anatomic Referencing in PET and SPECT: Radiation Dose, Biologic Damage, and Image Quality

Kersemans¹,

Thompson²,

Cornelissen³

et al. 2011

J Nucl Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…Notwithstanding, the impact high dose CT has on longitudinal experimental results remains controversial. Studies often report opposing findings from no effects regarding dose delivered to tumors during longitudinal studies to results indicating high doses can induce tumor inhibition [19,20,[34][35][36]. Using a Mediso nanoPET/CT scanner, we found that for both the air/water and the TEM phantoms, decreasing CT dose resulted in visual image quality degradation and high noise, but had a relatively minimal impact on HU quantification, while adversely increasing small animal absorbed dose.…”

Section: Discussionmentioning

confidence: 74%

“…Therefore, the impact of varying microCT parameters on microPET/CT data and preclinical research results is poorly defined and not fully understood. Furthermore, the significance of different microCT parameters on radiation exposure to small laboratory animals is scarcely described in the literature [20], in particular cumulative severity for longitudinal studies. Given that cumulative radiation doses can become increasingly toxic [21], accurate microCT absorbed dose measurements are essential when undertaking longitudinal preclinical research.…”

Section: Introductionmentioning

confidence: 99%

High Dose MicroCT Does Not Contribute Toward Improved MicroPET/CT Image Quantitative Accuracy and Can Limit Longitudinal Scanning of Small Animals

et al. 2017

View full text Add to dashboard Cite

Obtaining accurate quantitative measurements in preclinical Positron Emission Tomography/Computed Tomography (PET/CT) imaging is of paramount importance in biomedical research and helps supporting efficient translation of preclinical results to the clinic. The purpose of this study was two-fold: (1) to investigate the effects of different CT acquisition protocols on PET/CT image quality and data quantification; and (2) to evaluate the absorbed dose associated with varying CT parameters.Methods: An air/water quality control CT phantom, tissue equivalent material phantom, an in-house 3D printed phantom and an image quality PET/CT phantom were imaged using a Mediso nanoPET/CT scanner. Collected data was analyzed using PMOD software, VivoQuant software and National Electric Manufactures Association (NEMA) software implemented by Mediso. Measured Hounsfield Unit (HU) in collected CT images were compared to the known HU values and image noise was quantified. PET recovery coefficients (RC), uniformity and quantitative bias were also measured.Results: Only less than 2 and 1% of CT acquisition protocols yielded water HU values < −80 and air HU values < −840, respectively. Four out of 11 CT protocols resulted in more than 100 mGy absorbed dose. Different CT protocols did not impact PET uniformity and RC, and resulted in <4% overall bias relative to expected radioactive concentration.Conclusion: Preclinical CT protocols with increased exposure times can result in high absorbed doses to the small animals. These should be avoided, as they do not contributed toward improved microPET/CT image quantitative accuracy and could limit longitudinal scanning of small animals.

show abstract

“…However, because of the geometry of the mouse, the requirement for deep sedation and, therefore, poor lung motility leading to atelectasis, this modality is not easily translated to murine models. Additionally, CT has the disadvantages of requiring long acquisitions and of exposing the animal to high doses of radiation, which could affect some research studies (22). MRI, on the other hand, is more sensitive for pulmonary metastases and can be used for longitudinal studies of tumor development and therapeutic response, without the confounding variable of ionizing radiation.…”

Section: Discussionmentioning

confidence: 99%

PET of HER2-Positive Pulmonary Metastases with ¹⁸F-Z_HER2:342 Affibody in a Murine Model of Breast Cancer: Comparison with ¹⁸F-FDG

et al. 2012

View full text Add to dashboard Cite

Targeted therapies often depend on the expression of the target present in the tumor. This expression can be difficult to ascertain in widespread metastases. 18 F-FDG PET/CT, although sensitive, is nonspecific for particular tumor markers. Here, we compare the use of a human epidermal growth factor receptor 2 (HER2)-specific 18 F-Z HER2:342 -Affibody and 18 F-FDG in HER2-expressing pulmonary metastases in a murine model of breast cancer. Methods: The lung metastasis model was established by intravenous injection of MDA-MB-231 HER2 -Luc human breast cancer cells into the tail vein. Bioluminescence imaging was used to evaluate metastasis progression. Uptake of 18 F-Z HER2:342 -Affibody and 18 F-FDG was confirmed by coregistration of the PET images with MR and CT images. At the end of the study, the presence of neoplastic cells and HER2 expression in lung tissues, and distribution of the tracer, were assessed ex vivo by immunohistochemistry and autoradiography. Results: 18 F-Z HER2:342 -Affibody successfully targeted HER2-positive lesions in the lung and allowed detection of metastases as early as 9 wk after injection of cells. In contrast, 18 F-FDG uptake was often masked by surrounding inflammatory changes and was nonspecific for HER2 expression. HER2 expression at a cellular level correlated well with tracer uptake on autoradiography. Conclusion: 18 F-Z HER2:342 -Affibody is a promising tracer for evaluation of HER2 status of breast cancer metastases and is more specific for detecting HER2-positive lesions than 18 F-FDG.

show abstract

Evaluation of the radiation dose in micro‐CT with optimization of the scan protocol

Abstract: The radiation dose of a standard micro-CT scan is relatively high and could influence the experimental outcome. We believe that the presented adaptation of the scan protocol allows for accurate imaging without the risk of interfering with the experimental outcome of the study.

Cited by 74 publications

References 23 publications

Micro-CT for Anatomic Referencing in PET and SPECT: Radiation Dose, Biologic Damage, and Image Quality

Micro-CT for Anatomic Referencing in PET and SPECT: Radiation Dose, Biologic Damage, and Image Quality

High Dose MicroCT Does Not Contribute Toward Improved MicroPET/CT Image Quantitative Accuracy and Can Limit Longitudinal Scanning of Small Animals

PET of HER2-Positive Pulmonary Metastases with ¹⁸F-Z_HER2:342 Affibody in a Murine Model of Breast Cancer: Comparison with ¹⁸F-FDG

Contact Info

Product

Resources

About

Evaluation of the radiation dose in micro‐CT with optimization of the scan protocol

Abstract: The radiation dose of a standard micro-CT scan is relatively high and could influence the experimental outcome. We believe that the presented adaptation of the scan protocol allows for accurate imaging without the risk of interfering with the experimental outcome of the study.

Cited by 74 publications

References 23 publications

Micro-CT for Anatomic Referencing in PET and SPECT: Radiation Dose, Biologic Damage, and Image Quality

Micro-CT for Anatomic Referencing in PET and SPECT: Radiation Dose, Biologic Damage, and Image Quality

High Dose MicroCT Does Not Contribute Toward Improved MicroPET/CT Image Quantitative Accuracy and Can Limit Longitudinal Scanning of Small Animals

PET of HER2-Positive Pulmonary Metastases with 18F-ZHER2:342 Affibody in a Murine Model of Breast Cancer: Comparison with 18F-FDG

Contact Info

Product

Resources

About

PET of HER2-Positive Pulmonary Metastases with ¹⁸F-Z_HER2:342 Affibody in a Murine Model of Breast Cancer: Comparison with ¹⁸F-FDG