Biomedical subjects

Gerald Antoch

Publications and source records attributed to Gerald Antoch.

At least 19 recordsLinked to original sources

PubMed2007

Can PET/CT replace separate diagnostic CT for cancer imaging? Optimizing CT protocols for imaging cancers of the chest and abdomen.

Stage-adapted treatment in oncology relies on correct tumor staging for patients with malignant diseases. To ensure accurate assessment of the tumor stage in thoracic and abdominal diseases by PET/CT, both CT and PET need to be optimized. In this setting, different malignant diseases require customized imaging protocols. Although in the clinical setting of therapy assessment, PET/CT with integration of low-dose, nonenhanced CT may be sufficient, tumor staging may require a more sophisticated CT protocol. This review focuses on potential CT protocols for imaging cancers of the chest and abdomen. Examples of CT protocols are presented and discussed for non-small cell lung cancer, breast cancer, colorectal cancer, gastrointestinal stromal tumors, and interventional liver therapy.

Abdominal Neoplasms↗

PubMed2006

Diagnostic accuracy of colorectal cancer staging with whole-body PET/CT colonography.

CONTEXT: Staging of patients with colorectal cancer often requires a multimodality, multistep imaging approach. Colonography composed of a combined modality of positron emission tomography (PET) and computed tomography (CT) provides whole-body tumor staging in a single session. OBJECTIVES: To determine the staging accuracy of whole-body PET/CT colonography compared with the staging accuracies of CT followed by PET (CT + PET) and CT alone and to evaluate the effect of PET/CT colonography on therapy planning compared with conventional staging (CT of the abdomen and thorax and optical colonoscopy). DESIGN, SETTING, AND PATIENTS: Prospective study of 47 patients enrolled between May 2004 and June 2006 with clinical findings and optical colonoscopy that suggested primary colorectal cancer (mean [SD] age, 71 [11] years; range, 47-92 years). Patients underwent whole-body PET/CT colonography 1 day after colonoscopy. The study was conducted at a university hospital with a mean (SD) follow-up of 447 (140) days (range, 232-653 days). MAIN OUTCOME MEASURES: Correct classification of overall TNM stage using PET/CT colonography compared with CT + PET and CT alone. Secondary outcome measures were the accurate assessment of T-stage, N-stage, and M-stage by PET/CT colonography compared with CT + PET and CT alone and the effect of PET/CT colonography on therapy planning. RESULTS: Of the 47 patients with a total of 50 lesions, the overall TNM stage was correctly determined for 37 lesions with PET/CT colonography (74%; 95% confidence interval [CI], 60%-85%), 32 lesions with CT + PET (64%; 95% CI, 49%-77%), and 26 lesions with CT alone with a 0.7-cm node threshold (52%; 95% CI, 37%-66%). Compared with optimized abdominal CT staging alone, PET/CT colonography was significantly more accurate in defining TNM stage (difference, 22%; 95% CI, 9%-36%; P=.003), which was mainly based on a more accurate definition of the T-stage. Differences were not detected for defining N-stage between PET/CT colonography and CT alone with a threshold of 0.7 cm for malignant nodes but were detected with a threshold of 1 cm. Differences were not detected in defining M-stage separately or when comparing the accuracies of PET/CT colonography with CT + PET. PET/CT colonography affected consecutive therapy decisions in 4 patients (9%; 95% CI, 2.4%-20.4%) compared with conventional staging (CT alone and colonoscopy). CONCLUSIONS: In this preliminary study, PET/CT colonography is at least equivalent to CT + PET for tumor staging in patients with colorectal cancer. Thus, PET/CT colonography in conjunction with optical colonoscopy may be a suitable concept of tumor staging for patients with colorectal cancer.

Aged↗

PubMed2006

Accuracy of combined PET/CT in image-guided interventions of liver lesions: an ex-vivo study.

AIM: Positioning of interventional devices in liver lesions is a challenging task if only CT is available. We investigated the potential benefit of combined PET/CT images for localization of interventional devices in interventional liver studies. METHODS: Thirty lesions each of hyperdense, isodense and hypodense attenuation compared to normal liver parenchyma were injected into 15 ex-vivo pig livers. All lesions were composed of the same amounts of gelatine containing 0.5 MBq of (18)F-FDG. Following lesion insertion, an interventional needle was placed in each lesion under CT-guidance solely. After that, a PET/CT study was performed. The localization of the needle within the lesion was assessed for CT alone and PET/CT and the root mean square (RMS) was calculated. Results were compared with macroscopic measurements after lesion dissection serving as the standard of reference. RESULTS: In hypo- and isodense lesions PET/CT proved more accurate in defining the position of the interventional device when compared with CT alone. The mean RMS for CT and PET/CT differed significantly in isodense and hypodense lesions. No significant difference was found for hyperdense lesions. CONCLUSION: Combined FDG-PET/CT imaging provides more accurate information than CT alone concerning the needle position in FDG-PET positive liver lesions. Therefore combined PET/CT might be potentially beneficial not only for localization of an interventional device, but may also be beneficial for guidance in interventional liver procedures.

Animals↗

PubMed2006

Lymph node staging with dual-modality PET/CT: enhancing the diagnostic accuracy in oncology.

Lymph node staging according to the TNM criteria is an essential part of tumor evaluation. Several morphological and functional imaging procedures are used complementarily in this setting. Dual-modality PET/CT scanners are able to provide anatomical and functional data sets in a single session with accurate image co-registration. Comparative studies between morphological imaging procedures, such as MRI and CT, with co-registered PET/CT demonstrated significantly better lymph node staging with PET/CT than with anatomical procedures alone, regardless of the staged body compartment (head and neck, thorax or abdominal area). Based on more accurate staging results, PET/CT was able to alter the patients' therapy in a significant number of studies. Functional imaging with FDG-PET ([(18)F]-2-fluoro-2-desoxy-D-glucose-positron emission tomography) demonstrated outstanding results in lymph node staging of different tumor diseases. By adding anatomical information to PET, PET/CT outperforms PET alone when assessing the TNM-stage of different malignant diseases. This paper provides an overview concerning the performance of PET/CT in staging lymph nodes for malignant spread and points out benefits and limitations of this new imaging modality.

Contrast Media↗

PubMed2006

Value of 18F-fluoro-2-deoxy-D-glucose-positron emission tomography/computed tomography in non-small-cell lung cancer for prediction of pathologic response and times to relapse after neoadjuvant chemoradiotherapy.

PURPOSE: To determine the value of combined positron emission tomography/computed tomography (PET/CT) during induction chemotherapy (CTx) followed by chemoradiotherapy (CTx/RTx) for non-small-cell lung cancer to predict histopathologic response in primary tumor and mediastinum and prognosis of the patient. EXPERIMENTAL DESIGN: Fifty consecutive patients with locally advanced non-small-cell lung cancer received induction therapy and, if considered resectable, proceeded to surgery (37 of 50 patients). Patients had at least two repeated 18F-2-fluoro-2-deoxy-D-glucose (FDG)-PET/CT scans either before treatment (t0) or after induction CTx (t1) or CTx/RTx (t2). Variables from the PET/CT studies [e.g., lesion volume and corrected maximum standardized glucose uptake values (SUV(max,corr))] were correlated with histopathologic response (graded as 3, 2b, or 2a: 0%, >0-10%, or >10% residual tumor cells) and times to failure. RESULTS: Primary tumors showed a percentage decrease in SUV(max,corr) during induction significantly larger in grade 2b/3 than in grade 2a responding tumors (67% versus 34% at t(1), 73% versus 49% at t(2); both P < 0.005). SUV(max,corr) at t(2) was significantly correlated with histopathologic response in tumors smaller than the median volume (7.5 cm(3); r = -0.54, P = 0.02). In the mediastinal lymph nodes, SUV(max,corr) values at t2 predicted an ypN0 status with a sensitivity and specificity of 73% and 89%, respectively (SUV(max,corr) threshold of 4.1, r = -0.54, P = 0.0005). Freedom from extracerebral relapse was significantly better in grade 2b/3 patients (86% at 16 months versus 20% in 2a responders; P = 0.003) and in patients with a greater percentage decrease in SUV(max,corr) in the primary tumor at t2 in relation to t0 than in patients with lesser response (83% at 16 months versus 43%; P = 0.03 for cutoff points between 0.45 and 0.55). CONCLUSIONS: SUV(max,corr) values from two serial PET/CT scans, before and after three chemotherapy cycles or later, allow prediction of histopathologic response in the primary tumor and mediastinal lymph nodes and have prognostic value.

Adult↗

PubMed2005

False-positive FDG PET uptake--the role of PET/CT.

Positron emission tomography (PET) is a powerful molecular imaging technique for the human body-imaging applications currently available. As altered glucose metabolism is characteristic for many malignancies, FDG-PET is mostly used in oncology for staging and therapy control. Although PET is a sensitive tool for detecting malignancy, FDG uptake is not tumor specific. It can also be seen in healthy tissue or in benign disease as inflammation or posttraumatic repair and could be mistaken for cancer. The experienced nuclear medicine physician mostly manages to differentiate malignant from non-malignant FDG uptake, but some findings may remain ambiguous. In these cases, the difficulties in differentiating physiologic variants or benign causes of FDG uptake from tumor tissue can often be overcome by combined PET and CT (PET/CT) as anatomic information is added to the metabolic data. Thus, PET/CT improves the diagnostic accuracy compared to PET alone and helps to avoid unnecessary surgery/therapy. However, PET/CT involves other sources of artifacts that may occur when using CT for attenuation correction of PET or by patient motion caused by respiration or bowel movements.

Artifacts↗

PubMed2005

Resection of residual disease in patients with metastatic gastrointestinal stromal tumors responding to treatment with imatinib.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Long-term survival of patients with metastatic disease has only been observed in patients with completely resected disease. Recently, the tyrosine kinase inhibitor imatinib has been found to yield responses in the majority of patients with metastatic GIST suggesting improved resectability in responding patients. Combined treatment approaches including resective surgery after imatinib treatment in patients with advanced metastatic disease have rarely been explored. We report a series of 90 patients with metastatic GIST in whom treatment with imatinib enabled 12 patients with mostly recurrent and extensive disease to be considered for resection of residual disease. In 11 of these patients, complete resection could be achieved. Viable tumor cells were found in all but one resected specimens suggesting that despite favorable radiological or clinical responses, imatinib is unlikely to induce pathological complete responses. Until more mature data from prospective trials are available, these data suggest that an early aggressive surgical approach should be considered for all patients with metastatic GIST. Further trials investigating a combined surgical and pre/postoperative treatment with imatinib in patients with advanced metastatic GIST are warranted.

Adult↗

PubMed2005

Detection of residual tumor after radiofrequency ablation of liver metastasis with dual-modality PET/CT: initial results.

The aim of this study was to determine the accuracy of dual-modality positron emission tomography(PET)/computed tomography (CT) in the detection of residual tumor after radiofrequency ablation (RFA) of liver metastasis of colorectal cancer. Eleven patients with 16 hepatic metastases (mean size 2.9 cm) from colorectal cancer were enrolled in this study, and 19 RFA procedures and 32 PET/CT examinations were performed. The patients had PET/CT before and after RFA using [18F]-2-fluoro-2-deoxy-D: -glucose. CT images alone were read by two radiologists, PET images alone were evaluated by two nuclear physicians. Fused images were read by one physician of each speciality in consensus. The accuracy for detection of residual tumor by the different imaging modalities following RFA was assessed. Eleven patients with a mean age of 63 (range 55-71) years were evaluated. The mean follow-up period was 393 days. The overall procedure-based sensitivity for detection of residual tumor was 65% for PET and PET/CT and 44% for CT alone. The accuracies were 68% and 47%, respectively. Four patients had residual tumor after RFA, six patients total developed local recurrence. PET/CT therefore possibly proved superior to CT alone when assessing the liver for residual tumor after RFA.

Aged↗

PubMed2005

Parallel acquisition techniques for accelerated volumetric interpolated breath-hold examination magnetic resonance imaging of the upper abdomen: assessment of image quality and lesion conspicuity.

PURPOSE: To evaluate the impact of parallel acquisition techniques (PATs) on image quality and detection of liver metastases using three-dimensional volumetric interpolated breath-hold examination (VIBE) for clinical liver imaging. MATERIALS AND METHODS: Forty-nine patients with various primary malignancies underwent abdominal dynamic contrast-enhanced three-dimensional VIBE magnetic resonance imaging (MRI) (1.5 T) using a standard phased array coil. Recently introduced Generalized Autocalibrating Partially Parallel Acquisition (GRAPPA) and SENSitivity Encoding (mSENSE) PAT reconstruction algorithms were added to reduce scan time twofold. Overall image quality, motion, and aliasing artifacts were classified on a 5-point scale. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurements were performed for quantitative comparison. All sequences were evaluated concerning the number of detected lesions. RESULTS: PAT resulted in a reduction of data acquisition time from 23 to 13 seconds. Both GRAPPA and mSENSE data sets yielded 30% less SNR (34.8 +/- 14.1 and 33.1 +/- 13.3, P < 0.001) and 35% less CNR (21.2 +/- 15.0 and 20.9 +/- 12.7, P < 0.05) in comparison to unaccelerated VIBE (SNR = 50.8 +/- 20.3/CNR = 32.5 +/- 19.1). Similarly, PAT revealed lower-image-quality scores than unaccelerated VIBE. GRAPPA resulted in more fold-over artifacts than mSENSE. mSENSE revealed slightly fewer motion artifacts than no PAT. The unaccelerated late-venous-phase VIBE sequence revealed 146 lesions in the same patients. Accelerated images with mSENSE reconstruction detected 138 lesions. GRAPPA revealed 127 lesions, and thus performed inferior to mSENSE. CONCLUSION: At least for arrays with small numbers of elements, such as arrays used in this study, the PAT-induced reduction in scanning times must be weighed against compromises in image quality, which translate into poorer diagnostic performance regarding detection of small hepatic lesions. Thus, the PAT implementations tested in this study should probably be reserved for patients unable to hold their breaths for regular three-dimensional VIBE data sets.

Abdomen↗

PubMed2005

Positron emission tomography/computed tomography improves diagnostics of inflammatory arteritis.

Based on the unique property of fluorine-18 fluorodeoxyglucose, localization and follow-up of hypermetabolic processes is possible with positron emission tomography (PET). The dual-modality PET/computed tomography (CT) systems provide intrinsically fused morphologic and functional data in a single examination. We report on two patients with inflammatory aortitis and positive PET/CT findings. A 57-year-old woman with an inflammatory process involving the thoracolumbal aorta with an aneurysm and a 48-year-old woman with an aneurysm of the thoracic aorta and pronounced fluorodeoxyglucose-uptake. The advantages in differentiation of vessel wall structures compared with PET or CT alone are pointed out.

Aortic Aneurysm↗

PubMed2005

Strategies in detection of the primary tumour in anti-Yo associated paraneoplastic cerebellar degeneration.

In patients with anti-Yo associated paraneoplastic cerebellar degeneration (PCD) neurological symptoms precede the diagnosis of the underlying cancer in about 60%. Ovarian carcinoma, breast cancer and other gynaecological malignancies are most frequently found as causative malignancies. Antitumour treatment should be applied in an early stage of disease. The identification of the tumour is a diagnostic challenge in many of these patients. In the first of two patients reported here a pelvic tumour was suggested after detection of a pathological lymph node and elevated tumour markers. The intraoperative findings appeared macroscopically normal during ovariectomy with adnexectomy. Not until microscopic examination of the resected tissue was performed was a tubal adenocarcinoma found. If intrapelvic gynaecological tumours are suspected a deliberate surgical exploration seems to be justified, but only after an intensive diagnostic investigation. To search for the underlying cancer in patients with paraneoplastic neurological disorders successive CT and [18F]-FDG-PET are widely recommended. Instead of this in the second reported patient whole-body dual-modality PET/CT was performed revealing enhanced uptake in three regions of the left thorax. By combining function and anatomy PET/CT was able to localise the lesions and characterise them as lymph node metastases of breast cancer. Diagnosis could be confirmed by subsequently executed needle biopsy. PET/CT seems to be highly applicable in the investigation of paraneoplastic disorders with unknown primary cancer. It may help in guidance of needle biopsy or to optimise the results of deliberate surgery and it provides whole-body tumour staging in a single session with higher diagnostic accuracy than PET alone.

Adenocarcinoma↗

PubMed2005

Evaluation of integrated whole-body PET/CT in the detection of recurrent ovarian cancer.

PURPOSE: To assess the usefulness and reliability of integrated whole-body positron emission tomography/computed tomography (PET/CT) in patients in whom recurrent ovarian cancer is suspected. METHODS: Integrated whole-body PET/CT imaging was performed in 19 patients with suspected ovarian cancer recurrence. CT, PET and fused PET/CT images were evaluated separately and imaging results were compared with pathological findings and clinical follow-up after 6 months. RESULTS: Of the 19 patients studied, 11 were found to have recurrent cancer. In 8 of these 11 patients, recurrence was diagnosed by CT, PET and fused PET/CT. In the remaining three patients, only PET and PET/CT showed a recurrent tumour, while CT was negative. Twelve localisations of ovarian cancer recurrence could be detected by CT, 17 by PET and 18 by PET/CT. In one patient with pulmonary metastases in CT and in the CT component of PET/CT, PET was negative. In the case of three metastases in the diaphragm, the spleen and the thoracic wall, respectively, the determination of the exact localisation was only possible by fused PET/CT. CONCLUSION: In patients with recurrent ovarian cancer, PET/CT detects more lesions than PET or CT alone. PET/CT permits the exact anatomical localisation of pathologic tracer uptake and can thus direct further treatment to the precise site of tumour recurrence. Hence, PET/CT should be considered for follow-up of patients with ovarian cancer.

Aged↗

PubMed2005

Contrast-enhanced dark lumen PET/CT and MR colonography in a rodent polyp model: initial results with histopathologic correlation.

OBJECTIVE: The objective of this study was to assess the feasibility of PET/CT for the detection of colorectal masses in a rodent polyp model in an intraindividual comparison with dark-lumen MR colonography. CONCLUSION: Detection of small tumors with PET/CT and MR colonography is possible in a rodent model. The technique thus warrants further evaluation in animal studies as well as in patients with suspected colorectal disease.

Animals↗

PubMed2005

Optimized intravenous contrast administration for diagnostic whole-body 18F-FDG PET/CT.

UNLABELLED: Standard application of CT intravenous contrast agents in combined PET/CT may lead to high-density artifacts on CT and attenuation-corrected PET. To avoid associated diagnostic pitfalls, we designed and compared different intravenous contrast injection protocols for routine whole-body PET/CT. METHODS: Whole-body PET/CT included a topogram and a single spiral CT scan (2-row) with or without intravenous contrast, followed by an emission scan. The CT scan was used for attenuation correction of the emission data. Four groups of 10 whole-body PET/CT referrals each were investigated: (A) no intravenous contrast agent, (B) biphasic injection (90 and 50 mL at 3 and 1.5 mL/s, respectively) of intravenous contrast (300 mg/mL iodine) and CT in the craniocaudal direction with a 30-s delay, (C) triple-phase injection (90, 40, and 40 mL at 3, 2, and 1.5 mL/s, respectively) in the craniocaudal direction with a 50-s delay, and (D) dual-phase injection (80 and 60 mL at 3 and 1.5 mL/s, respectively) in the caudocranial direction with a 50-s delay. CT image quality was assessed on a scale from 1 to 3, and CT and attenuation-corrected PET images were reviewed separately for contrast-induced artifacts. RESULTS: Average CT image quality was poorest for protocol A (1.0) but improved to 2.8 when using intravenous contrast agents (protocols B-D). Only protocols B and C resulted in contrast-induced image artifacts that were limited to the thorax. The most homogeneous intravenous contrast enhancement without high-density image artifacts on either CT or PET after CT-based attenuation correction was achieved with protocol D. CONCLUSION: Dual-phase intravenous contrast injection and CT in the caudocranial direction with a 50-s delay yields reproducible high image quality and is now used routinely for combined diagnostic PET/CT at our hospital.

Contrast Media↗

PubMed2005

Assessment of liver tissue after radiofrequency ablation: findings with different imaging procedures.

UNLABELLED: Our goal was to assess the typical appearance of normal liver tissue immediately after radiofrequency ablation (RF-ablation) when imaged with contrast-enhanced ultrasound, CT, MRI, 18F-FDG PET, and PET/CT. METHODS: Nineteen RF-ablation sessions were performed on nontumorous liver tissue of 10 Göttingen Mini Pigs. CT, ultrasound, MRI, 18F-FDG PET, and PET/CT were performed immediately after the intervention. All imaging procedures were evaluated qualitatively for areas of increased contrast enhancement (morphologic imaging) and regions of elevated tracer uptake (functional imaging). Images were assessed quantitatively by determination of ratios (r(p/p)) comparing contrast enhancement/tracer uptake in the periphery of the necrosis with contrast enhancement/tracer uptake of normal liver parenchyma. RESULTS: On morphologic imaging, an increase in contrast enhancement surrounding the ablative necrosis was detected in all lesions. Quantification of this area of increased contrast enhancement revealed ratios of r(p/p) = 1.57 +/- 0.2 for CT and r(p/p) = 1.57 +/- 0.19 for MRI. On PET and PET/CT, homogeneous tracer utilization was found surrounding all lesions. There were no areas of a focal or rim-like increase in glucose metabolism. The ratio r(p/p) was found to be 1.05 +/- 0.08 for functional data. Histologic examination revealed pooling of blood in the sinusoids of the lesion's periphery that was caused by outflow obstruction due to the central necrosis. CONCLUSION: On morphologic imaging, a rim-like increase of contrast enhancement was found immediately after RF-ablation resembling peripheral hyperperfusion. This area of contrast enhancement may hamper detection of residual tumor. On the basis of homogeneous tracer distribution surrounding the area of necrosis, PET and PET/CT may serve for early assessment of patients after RF-ablation.

Animals↗

PubMed2004

Unknown primary tumors: detection with dual-modality PET/CT--initial experience.

PURPOSE: To retrospectively evaluate fused positron emission tomography (PET)/computed tomography (CT) in depicting the primary lesion in cancer of an unknown primary tumor, compared with PET, CT, and PET and CT side-by-side evaluation. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Forty-five patients (26 men and 19 women) with metastatic cervical adenopathy (n = 18) or extracervical metastases (n = 27) of unknown primary tumor were included. The mean age of the patients was 57 years (range, 29-95 years). PET/CT imaging was performed in all patients 1 hour after administration of 350 MBq of fluorodeoxyglucose with a whole-body field of view. Contrast agents were administered orally and intravenously in all patients to ensure diagnostic CT data. PET/CT data sets were evaluated for the primary tumor, and imaging results were compared with those of CT, PET, and PET and CT side-by-side evaluation. Differences in diagnostic performance were assessed by using the McNemar test with Bonferroni correction, which accounts for multiple comparisons. RESULTS: PET/CT depicted the primary tumor in 15 (33%) of 45 patients. In 30 (67%) patients, the primary tumor site remained occult (P > .05). PET and CT side-by-side evaluation depicted 13 (29%) of 45 tumors (P > .05). PET alone revealed the primary tumor in 11 (24%) of 45 patients (P > .05), while CT alone helped in the correct diagnosis in eight (18%) of 45 patients (P > .05). There were no significant differences between the diagnostic accuracies of PET/CT and the other imaging modalities. CONCLUSION: PET/CT was able to depict more primary tumors, though not significantly, than either of the other imaging modalities, but larger patient cohorts are required to finally judge its value for revealing the primary tumor site.

Adult↗

PubMed2004

Accuracy of whole-body dual-modality fluorine-18-2-fluoro-2-deoxy-D-glucose positron emission tomography and computed tomography (FDG-PET/CT) for tumor staging in solid tumors: comparison with CT and PET.

PURPOSE: To assess the accuracy of positron emission tomography/computed tomography (PET/CT) when staging different malignant diseases. PATIENTS AND METHODS: This was a retrospective, blinded, investigator-initiated study of 260 patients with various oncological diseases who underwent fluorine-18-2-fluoro-2-deoxy-d-glucose PET/CT for tumor staging. CT images alone, PET images alone, PET + CT data viewed side by side, and fused PET/CT images were evaluated separately according to the tumor-node-metastasis system. One hundred forty patients with tumors not staged according to the tumor-node-metastasis system or a lack of reference standard were excluded from data analysis; 260 patients were included. Diagnostic accuracies were determined for each of the four image sets. Histopathology and a clinical follow-up of 311 (+/- 125) days served as standards of reference. RESULTS: PET/CT proved significantly more accurate in assessing tumor-node-metastasis system stage compared with CT alone, PET alone, and side-by-side PET + CT (P < .0001). Of 260 patients, 218 (84%; 95% CI, 79% to 88%) were correctly staged with PET/CT, 197 (76%; 95% CI, 70% to 81%) with side-by-side PET + CT, 163 (63%; 95% CI, 57% to 69%) with CT alone, and 166 (64%; 95% CI, 58% to 70%) with PET alone. Combined PET/CT had an impact on the treatment plan in 16, 39, and 43 patients when compared with PET + CT, CT alone, and PET alone, respectively. CONCLUSION: Tumor staging with PET/CT is significantly more accurate than CT alone, PET alone, and side-by-side PET + CT. This diagnostic advantage translates into treatment plan changes in a substantial number of patients.

Adolescent↗

PubMed2004

Intraoperative radiation therapy in liver tissue in a pig model: monitoring with dual-modality PET/CT.

PURPOSE: To assess, in a pig model, the value of dual-modality positron emission tomography (PET)/computed tomography (CT) for monitoring radiation therapy. MATERIALS AND METHODS: Central bile duct resection followed by creation of a biliodigestive anastomosis was performed in nine pigs. Six of these pigs were also treated with intraoperative radiation therapy (IORT) (20 Gy) in the area of the anastomosis. Two, 4, and 8 weeks postoperatively, contrast material-enhanced fluorine 18 fluorodeoxyglucose (FDG) PET/CT of the liver was performed in all of the animals. The radioactive tracer concentration in the region of the anastomosis was quantified, and the values were compared intraindividually with the values at the liver periphery. Histologic evaluation of the liver was performed 8 weeks postoperatively. The PET/CT images were assessed for changes in liver volume and bile duct diameter over time. RESULTS: In all nine pigs, the region of the anastomosis could be clearly defined on the fused PET/CT images. PET/CT revealed a decreased concentration of FDG in the irradiated field 2 and 4 weeks after IORT. At 8 weeks, however, the distribution of the tracer in the irradiated pigs did not differ from that in the nonirradiated pigs. Homogeneous tracer uptake in all liver regions was observed in the nonirradiated animals. The CT images showed an increase in liver volume in all pigs and bile duct dilatation that increased over time in the irradiated pigs. CONCLUSION: The morphologic and functional changes due to IORT in liver tissue can be accurately monitored with dual-modality PET/CT. By enabling the integration of functional and morphologic data, PET/CT may have an important role in monitoring radiation treatment.

Anastomosis, Roux-en-Y↗