Static and moving phantom studies for radiation treatment planning in a positron emission tomography and computed tomography (PET/CT) system

Okubo, Masaaki; Nishimura, Yasumasa; Nakamatsu, Kiyoshi; Okumura, Masahiko; Shibata, Toru; Kanamori, Shuichi; Hanaoka, Kouhei; Hosono, Makoto

doi:10.1007/s12149-008-0166-8

Cited by 29 publications

(39 citation statements)

References 39 publications

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“…We also determined the tumor volumes of true-positive lesions using an automated attenuation-corrected FDG PET method according to a previous study [12]. ROIs placed over true-positive lesions were drawn manually referring to fusion images or CT images.…”

Section: Discussionmentioning

confidence: 99%

Ability of 18F-FDG PET/CT to diagnose recurrent colorectal cancer in patients with elevated CEA concentrations

et al. 2010

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Section: Discussionmentioning

confidence: 99%

Ability of 18F-FDG PET/CT to diagnose recurrent colorectal cancer in patients with elevated CEA concentrations

et al. 2010

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“…N Two absolute threshold PET contours were delineated using an absolute standardised uptake value (SUV) threshold of 2.5 (GTV SUV2.5 ) and a threshold of 35% (GTV 35%SUVMAX ) of the maximal SUV within the target image (SUV MAX ) [16,17].…”

Section: Target Volume Delineationmentioning

confidence: 99%

“…Hence the PET component of the scan contains an element of the respiratory motion of a lung tumour. It has been suggested that this four-dimensional (4D) element of a PET scan might be able to define an internal target volume, compensating for all respiratory motion [16,23]. Thus, with current scanning protocols, a 3D scanning modality (CT) is in effect being combined with a 4D scanning modality (PET).…”

Section: Target Volume Delineationmentioning

confidence: 99%

Conventional 3D staging PET/CT in CT simulation for lung cancer: impact of rigid and deformable target volume alignments for radiotherapy treatment planning

Hanna

Koste

Carson³

et al. 2011

BJR

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Objective: Positron emission tomography (PET)/CT scans can improve target definition in radiotherapy for non-small cell lung cancer (NSCLC). As staging PET/CT scans are increasingly available, we evaluated different methods for co-registration of staging PET/CT data to radiotherapy simulation (RTP) scans. Methods: 10 patients underwent staging PET/CT followed by RTP PET/CT. On both scans, gross tumour volumes (GTVs) were delineated using CT (GTV CT ) and PET display settings. Four PET-based contours (manual delineation, two threshold methods and a source-to-background ratio method) were delineated. The CT component of the staging scan was co-registered using both rigid and deformable techniques to the CT component of RTP PET/CT. Subsequently rigid registration and deformation warps were used to transfer PET and CT contours from the staging scan to the RTP scan. Dice's similarity coefficient (DSC) was used to assess the registration accuracy of staging-based GTVs following both registration methods with the GTVs delineated on the RTP PET/CT scan. Results: When the GTV CT delineated on the staging scan after both rigid registration and deformation was compared with the GTV CT on the RTP scan, a significant improvement in overlap (registration) using deformation was observed (mean DSC 0.66 for rigid registration and 0.82 for deformable registration, p50.008). A similar comparison for PET contours revealed no significant improvement in overlap with the use of deformable registration. Conclusions: No consistent improvements in similarity measures were observed when deformable registration was used for transferring PET-based contours from a staging PET/CT. This suggests that currently the use of rigid registration remains the most appropriate method for RTP in NSCLC.

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“…Okubo et al [31] constructed an elliptic phantom and found that when a threshold value of 35% of the measured maximum 18 FDG activity was adopted, the sizes of PET delineation were almost the same for static and moving phantom spheres of 22 mm or more in the axial plane.…”

Section: Thresholding Methods For Target Outliningmentioning

confidence: 99%

“…An annular ring of water bags of 3 cm thickness was fitted over an International Electro-technical Commission (IEC) phantom in order to obtain counting rates similar to those found in average patients. They found that both the target size and the T/B ratio play a major role in explaining the variance of the percentage threshold throughout the whole range of target sizes and T/B ratios examined.Okubo et al [31] constructed an elliptic phantom and found that when a threshold value of 35% of the measured maximum 18 FDG activity was adopted, the sizes of PET delineation were almost the same for static and moving phantom spheres of 22 mm or more in the axial plane.Adaptive thresholding methods: Black et al [13] proposed an advanced adaptive threshold method for target delineation using PET images in which threshold value varies with the size of the target. However, they employed SUV, which does not represent the quantity of choice for the radiation treatment planning segmentation as mentioned previously [14].…”

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confidence: 99%

Towards Biological Target Volumes Definition for Radiotherapy Treatment Planning: Quo Vadis PET/CT?

Dević¹

2013

J Nucl Med Radiat Ther

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IntroductionRadiotherapy treatment planning (RTP) over the last few decades has been based on anatomical targets, namely gross tumor volume (GTV) and from it derived clinical target volume (CTV) as well as the planning target volume (PTV). Owing to its superb spatial reproducibility and the ability to provide the information on electron density (useful for heterogeneity corrections), computed tomography (CT) was, and it still represents, the backbone of modern/high technology radiotherapy treatment planning. The lack of sufficient soft tissue contrast in CT resulted in the incorporation of other imaging methods, such as the magnetic resonance imaging (MRI), into the target definition through the process of image co-registration (sometimes incorrectly termed as image fusion). Whereas the MRI has widely contributed to a better definition of the GTV, [1] which represents an anatomical volume, functional information has not been readily available in the framework of conformal 3D treatment planning and delivery in radiotherapy until recently. In addition, it has been widely accepted that a homogeneous dose delivery to the PTV is the standard of care one should pursue to achieve the best local tumor control.Integration of positron emission tomography (PET) and computed tomography (CT) scanners [2][3][4][5] introduced a new dimension in nuclear medicine by combining functional and anatomical imaging in one machine: the PET/CT scanner. Main advantages of PET/CT scanners are:9 Improved quality of reconstructed PET images with the use of a CT map for attenuation correction of emission PET scans 9 Decrease of about half of the PET acquisition time compared to the previous generation of PET scanners, which used an external radioactive source to acquire transmission scan for attenuation correction. In addition, new faster scintillation materials have also contributed to the shortening of the scanning time 9 The combined medical imaging modality is likely helping management of radiotherapy patients 9 Better understanding of tumor metabolic activity spatial localization by the ability to map the distribution of a specific radiopharmaceutical in co-registered PET/CT images, despite the relatively poor spatial resolution of PET image [6,7].With an increased access to PET/CT information and an apparent appreciation that different sections of the tumor functionally do not behave uniformly, radiation oncologists started to contemplate a change in the traditional concept of uniform dose to the PTV delivery. Instead, a notion of biological targeting and dose painting has come into the play. The first question that comes to our attention is how to define the biological target volumes (BTV) and what do they represent? Ten years after the introduction of the PET/CT scanners into the radiation oncology community, target delineation in radiotherapy treatment planning using FDG-PET/CT scans still has a lot of controversy. The aim of this article is to review the limitations of the current methods for the incorporation of FDG based PET/CT ...

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Static and moving phantom studies for radiation treatment planning in a positron emission tomography and computed tomography (PET/CT) system

Abstract: When a threshold value of 35% of the measured maximum (18)FDG activity was adopted, the sizes of PET delineation were almost the same for static and moving phantom spheres of 22 mm or more in the axial plane. In addition, PET images have the potential to provide an individualized ITV.

Cited by 29 publications

References 39 publications

Ability of 18F-FDG PET/CT to diagnose recurrent colorectal cancer in patients with elevated CEA concentrations

Ability of 18F-FDG PET/CT to diagnose recurrent colorectal cancer in patients with elevated CEA concentrations

Conventional 3D staging PET/CT in CT simulation for lung cancer: impact of rigid and deformable target volume alignments for radiotherapy treatment planning

Towards Biological Target Volumes Definition for Radiotherapy Treatment Planning: Quo Vadis PET/CT?

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