18F-FDG-PET-based tumor delineation in cervical cancer: Threshold contouring and lesion volumes

Erlich, F.; Camisão, C.; Nogueira-Rodrigues, A.; Altino, S.; Ferreira, Carlos Gil; Mamede, Marcelo

doi:10.1016/j.remn.2012.06.003

Cited by 5 publications

(4 citation statements)

References 16 publications

(15 reference statements)

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“…Thresholds between 15 to 60% of the maximum SUV have been studied across several tumour sites. [29][30][31][32] Further techniques have defined tumour based on the gradient of SUV change at the edge of a tumour. 33 These methods utilise complex image interpretation and derivation models to define the relevant PET metabolic borders.…”

Section: Introductionmentioning

confidence: 99%

Defining primary anal cancer tumour volume on FDG–PET – an initial assessment of semi–automated methods

Smith¹,

Joon²,

Schneider-Kolsky³

et al. 2021

IJRRT

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Purpose Clinician inexperience, intra–observer and inter–observer variations in tumour definition may affect staging, radiotherapy target definition, and treatment outcomes, particularly in rare cancers. The purpose of this study was to assess the correlation between semi–automated methods of primary anal cancer (AC) definition and our current clinical standard of manual clinician definition using 18F–FDG–PET imaging and to provide recommendations for clinical use. Methods All patients referred for chemoradiotherapy for AC between 2012 and 2016 were prospectively enrolled, with all 18F–FDG–PET imaging acquired within one year of chemoradiotherapy collected. Three methods of primary AC definition were performed on all PET datasets. Manual definition by an experienced radiologist was considered the clinical standard for comparison of volume and coincidence (Dice coefficient) in our study. Semi–automated techniques assessed included a gradient–based SUV (SUV–gradient) method and a SUV threshold method with a range of thresholds relative to SUVmax (40 (T40), 50 (T50) and 60% (T60)). Results Ten patients were enrolled with 33 PET study sets available for analysis. While all methods created contours on pre– and post–treatment scans, manual definition of PET–avid disease was only necessary on 11 of the 33 study sets. SUV–gradient and T40 defined contours were not statistically different in volume to the clinical standard (p = 0.83 & 0.72 respectively). The observed Dice coefficient relative to the manual clinician contours were 0.75 and 0.73 for the SUV–gradient and T40 methods respectively. Conclusions It is possible to define gross AC using SUV–based methods, with the SUV–gradient–based method followed by the T40 method most closely correlating with our current clinical standard. The SUV–gradient–based method studied is housed within a proprietary clinical system. A semi–automated approach that uses a vendor neutral T40 method and the clinician’s knowledge and skill appears optimal in defining AC. With this approach AC may be defined reliably to enhance efficiencies in radiotherapy and nuclear medicine processes, and to support clinicians in identifying and defining this rare disease. Trial registration ANZCTR, ACTRN12620000066987. Registered 28 January 2020–Retrospectively registered, https://www.anzctr.org.au/ACTRN12620000066987.aspx

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Section: Introductionmentioning

confidence: 99%

Defining primary anal cancer tumour volume on FDG–PET – an initial assessment of semi–automated methods

Smith¹,

Joon²,

Schneider-Kolsky³

et al. 2021

IJRRT

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“…FDG PET/CT utilises FDG, a glucose analogue, to provide valuable metabolic information based on the increased glucose uptake and glycolysis of cancer cells, and can depict metabolic abnormalities before morphological alterations occur [ 17 ]. FDG PET/CT has been employed to define radiotherapy targets using a threshold based on the standardised uptake value (SUV) for over a decade [ 18 ], and that for cervical cancer has been recently demonstrated [ 19 ]. Modification of radiation treatment volumes to FDG-avid lymph nodes and primary tumour can facilitate the accurate definition of tissues with metabolically active disease and the avoidance of normal tissue; hence allowing dose boosts to FDG-avid tumour volumes and lower doses to the bone marrow, urinary bladder and rectum [ 20 , 21 ].…”

Section: Introductionmentioning

confidence: 99%

Concordance of FDG PET/CT metabolic tumour volume versus DW-MRI functional tumour volume with T2-weighted anatomical tumour volume in cervical cancer

Lai

Perucho

et al. 2017

BMC Cancer

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Background 18F–fluoro-deoxyglucose positron emission tomography with computed tomography (FDG PET/CT) has been employed to define radiotherapy targets using a threshold based on the standardised uptake value (SUV), and has been described for use in cervical cancer. The aim of this study was to evaluate the concordance between the metabolic tumour volume (MTV) measured on FDG PET/CT and the anatomical tumour volume (ATV) measured on T2-weighted magnetic resonance imaging (T2W-MRI); and compared with the functional tumour volume (FTV) measured on diffusion-weighted MRI (DW-MRI) in cervical cancer, taking the T2W-ATV as gold standard.MethodsConsecutive newly diagnosed cervical cancer patients who underwent FDG PET/CT and DW-MRI were retrospectively reviewed from June 2013 to July 2017.Volumes of interest was inserted to the focal hypermetabolic activity corresponding to the cervical tumour on FDG PET/CT with automated tumour contouring and manual adjustment, based on SUV 20%–80% thresholds of the maximum SUV (SUVmax) to define the MTV20–80, with intervals of 5%.Tumour areas were manually delineated on T2W-MRI and multiplied by slice thickness to calculate the ATV.FTV were derived by manually delineating tumour area on ADC map, multiplied by the slice thickness to determine the FTV(manual). Diffusion restricted areas was extracted from b0 and ADC map using K-means clustering to determine the FTV(semi-automated).The ATVs, FTVs and the MTVs at different thresholds were compared using the mean and correlated using Pearson’s product-moment correlation.ResultsTwenty-nine patients were evaluated (median age 52 years). Paired difference of mean between ATV and MTV was the closest and not statistically significant at MTV30 (−2.9cm3, −5.2%, p = 0.301). This was less than the differences between ATV and FTV(semi-automated) (25.0cm3, 45.1%, p < 0.001) and FTV(manual) (11.2cm3, 20.1%, p = 0.001). The correlation of MTV30 with ATV was excellent (r = 0.968, p < 0.001) and better than that of the FTVs.ConclusionsOur study demonstrated that MTV30 was the only parameter investigated with no statistically significant difference with ATV, had the least absolute difference from ATV, and showed excellent positive correlation with ATV, suggesting its superiority as a functional imaging modality when compared with DW-MRI and supporting its use as a surrogate for ATV for radiotherapy tumour contouring.

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“…Many automatic segmentation methods have been suggested in literature over the last decade, but only fixed threshold‐based segmentation algorithms are available in commercial treatment planning systems (e.g., Eclipse from Varian). A number of clinical papers 9 , 10 , 11 still report work done using fixed threshold methods like absolute value of SUV (e.g.,

SUV = 2.5, 3, 5

) or percentage of the maximum intensity (40% or 50%), though it has largely been proven to be an oversimplification 12 , 13 , 14 , 15 . Adaptive threshold methods based on calibrated curves giving the threshold as a function of source‐to‐background ratio are superior to fixed threshold‐based segmentation 16 , 17 , 18 , 19 and are intuitively simpler to implement, especially in a setting of limited medical physics support.…”

Section: Introductionmentioning

confidence: 99%

Adaptive threshold segmentation of pituitary adenomas from FDG PET images for radiosurgery

Hecking

Devadhas

Heck

et al. 2014

J Applied Clin Med Phys

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In this study we have attempted to optimize a PET based adaptive threshold segmentation method for delineating small tumors, particularly in a background of high tracer activity. The metabolic nature of pituitary adenomas and the constraints of MRI imaging in the postoperative setting to delineate these tumors during radiosurgical procedures motivated us to develop this method. Phantom experiments were done to establish a relationship between the threshold required for segmenting the PET images and the target size and the activity concentration within the target in relation to its background. The threshold was developed from multiple linear regression of the experimental data optimized for tumor sizes less than 4 cm3. We validated our method against the phantom target volumes with measured target to background ratios ranging from 1.6 to 14.58. The method was tested on ten retrospective patients with residual growth hormone‐secreting pituitary adenomas that underwent radiosurgery and compared against the volumes delineated by manual method. The predicted volumes against the true volume of the phantom inserts gave a correlation coefficient of 99% (p<0.01). In the ten retrospective patients, the automatically segmented tumor volumes against volumes manually delineated by the clinicians had a correlation of 94% (p<0.01). This adaptive threshold segmentation showed promising results in delineating tumor volumes in pituitary adenomas planned for stereotactic radiosurgery, particularly in the postoperative setting where MR and CT images may be associated with artifacts, provided optimization experiment is carried out.PACS number: 87.57.nm, 87.57.uk

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18F-FDG-PET-based tumor delineation in cervical cancer: Threshold contouring and lesion volumes

Cited by 5 publications

References 16 publications

Defining primary anal cancer tumour volume on FDG–PET – an initial assessment of semi–automated methods

Defining primary anal cancer tumour volume on FDG–PET – an initial assessment of semi–automated methods

Concordance of FDG PET/CT metabolic tumour volume versus DW-MRI functional tumour volume with T2-weighted anatomical tumour volume in cervical cancer

Adaptive threshold segmentation of pituitary adenomas from FDG PET images for radiosurgery

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