PET/CT planning during chemoradiotherapy for esophageal cancer

Abstract

PurposeTo evaluate the usefulness of positron emission tomography/computed tomography (PET/CT) for field modification during radiotherapy in esophageal cancer.Materials and MethodsWe conducted a retrospective study on 33 patients that underwent chemoradiotherapy (CRT). Pathologic findings were squamous cell carcinoma in 32 patients and adenocarcinoma in 1 patient. All patients underwent PET/CT scans before and during CRT (after receiving 40 Gy and before a 20 Gy boost dose). Response evaluation was determined by PET/CT using metabolic tumor volume (MTV), total glycolytic activity (TGA), MTV ratio (rMTV) and TGA ratio (rTGA), or determined by CT. rMTV and rTGA were reduction ratio of MTV and TGA between before and during CRT, respectively.ResultsSignificant decreases in MTV (MTV2.5: mean 70.09%, p < 0.001) and TGA (TGA2.5: mean 79.08%, p<0.001) were found between before and during CRT. Median rMTV2.5 was 0.299 (range, 0 to 0.98) and median rTGA2.5 was 0.209 (range, 0 to 0.92). During CRT, PET/CT detected newly developed distant metastasis in 1 patient, and this resulted in a treatment strategy change. At a median 4 months (range, 0 to 12 months) after completion of CRT, 8 patients (24.2%) achieved clinically complete response, 11 (33.3%) partial response, 5 (15.2%) stable disease, and 9 (27.3%) disease progression. SUVmax (p = 0.029), rMTV50% (p = 0.016), rMTV75% (p = 0.023) on intra-treatment PET were found to correlate with complete clinical response.ConclusionPET/CT during CRT can provide additional information useful for radiotherapy planning and offer the potential for tumor response evaluation during CRT. rMTV50% during CRT was found to be a useful predictor of clinical response.

Radiomics in esophageal and gastric cancer

“…In esophageal cancer, PET has the potential to change management in up to a third of patients [21,22], and is often incorporated into radiotherapy planning pathway [23,24]. The American College of Surgeons Oncology Group reported sensitivity and specificity of 18F-FDG-PET/CT scans to be 79% and 95%, respectively [18].…”

Superiority of Deformable Image Co-registration in the Integration of Diagnostic Positron Emission Tomography-Computed Tomography to the Radiotherapy Treatment Planning Pathway for Oesophageal Carcinoma

“…These data require confirmation in a larger cohort. There is a lack of a validated method of GTV delineation using PET-CT, including the optimum SUV maximum threshold for delineating the metabolically active volume on the PET-CT [10][11][12][13]. A prior study focusing on cervical cancer showed that the minimum threshold representing tumour volume was 40% of maximum SUV with values less than this included additional background uptake [35].…”

“…PET-CT can assist in identifying the metabolically active tumour but there remains uncertainty in how this information should be used [9][10][11][12]. Some studies suggest PET-CT may enable more accurate tumour delineation, compared to CT alone [6,9,13]. There are many difficulties in integrating PET-CT to the treatment planning process; primarily because the staging PET-CT is typically acquired prior to a decision to proceed with non-surgical treatment.…”

Application of X‐Ray Computed Tomography Technology in Gas Hydrate

“…Because of the heterogeneity of the sediments in the nature, the effect of the distribution of sand size on the saturation of hydrates was studied by Seol and Kneafsey. [75] They found that with the influence of capillary force, the change of water saturation on fine sand was larger than that of coarse sand. The flaky clay was found in the Pearl River Mouth (PRM) basin by Wang et al [137] They believed that the flaky clay could promote the formation of hydrates by increasing the contact area.…”

“…The artificial gas hydrate-sediment samples [65][66][67][68][74][75] Samples of hydrate deposits in nature [69,[77][78][79][80][81] Measuring the permeability of hydrate sediment The artificial gas hydrate-sediment samples [82][83][84][85][86][87] Samples of hydrate deposits in nature [70,88,89] Identifying the occurrence mode of hydrate in sediments…”