Prostate cancer localization with 18fluorine fluorocholine positron emission tomography

PURPOSE: We evaluated positron emission tomography (PET) with fluorine fluorocholine (F FCH) for the pretreatment localization of prostate cancer. MATERIALS AND METHODS: A total of 17 patients with prostate cancer who had not yet received treatment for the disease underwent whole body PET following intravenous administration of 3.3 to 4 MBq/kg F FCH. PET findings were compared with the results of prostate sextant biopsy and other imaging studies, and the clinical course. Tracer uptake in prostate sextants was measured as a maximum standardized uptake value (SUVmax) and evaluated as a predictor of the prostate sextant biopsy result by ROC analysis. RESULTS: Prostate sextants positive for malignancy on biopsy demonstrated significantly higher SUVmax than biopsy negative sextants (mean 5.5 vs 3.3, p <0.001). In all 6 cases in which biopsy identified malignancy on only 1 side of the prostate it was possible to identify correctly the affected side based on higher SUVmax. Area under the ROC curve for SUVmax as a discriminator of biopsy positive sextants was 0.86. In 2 patients PET demonstrated areas of abnormal uptake in the retroperitoneum. Computerized tomography confirmed the presence of retroperitoneal lymphadenopathy in these areas. In the 2 patients these lesions regressed following hormonal treatment for prostate cancer. CONCLUSIONS: Malignant tumors in the prostate gland can be localized based on a standardized regional measurement of F FCH uptake. PET with F FCH is potentially useful for staging and localizing prostate cancer.     

Pulmonary metastatic melanoma -- the survival benefit associated with positron emission tomography scanning.

OBJECTIVE: Positron emission tomography (PET) scanning is more sensitive at detecting metastatic disease than conventional radiological techniques. For patients with pulmonary metastatic melanoma, we investigate if PET scanning to detect occult extra pulmonary disease prior to thoracotomy and metastectomy is associated with improved survival compared to patients staged by conventional radiology. METHODS: Between November 1984 and December 1999, 121 patients (90 males, 31 females) have undergone a thoracotomy and pulmonary metastectomy for metastatic melanoma. The age range was 19-84 years (mean 57, median 59). In every case all palpable nodules were removed and the diagnosis confirmed histologically. A total of 68 (56%) patients had a PET scan preoperatively, 53 (44%) underwent conventional or nuclear imaging. Patients with only radiologically isolated pulmonary disease are included. RESULTS: Survival is 100% complete and totals 238 pt/years (mean 2.2 years, median 1.4 years). Survival (+/-SE) at 1, 3, 5 and 7 years for all patients is 68% (+/-4.5) (n=67), 36.6% (+/-5.2) (n=27), 22.1% (+/-4.8) (n=15) and 13.5% (+/-4.2) (n=7), respectively. Survival (+/-SE) was significantly better at 3 and 5 years in patients who underwent a PET scan preoperatively (Log rank P=0.002). There was no significant difference in survival by 7 years. CONCLUSIONS: There is a significant survival benefit associated with excluding extra pulmonary disease using a PET scan prior to thoracotomy and metastectomy. We recommend that PET scanning be used in the investigation of patients with pulmonary metastatic melanoma prior to metastectomy.     

Acrometastasis and the potential benefits of early positron emission tomography scanning

A case report of a rare proximal phalanx metastasis from a primary lung carcinoma is described. The presenting symptom of the patient was pain in the proximal phalanx of the index finger. Radiographs at the time of presentation were unremarkable, and no diagnosis was provided. Because of increasing pain and eventual swelling, the patient presented for emergency assessment. Radiographs, less than 3 months after initial assessment, demonstrated a large lytic lesion within the proximal phalanx. Biopsy of the lesion documented a large cell malignancy consistent with a poorly differentiated adenocarcinoma. Subsequent investigations documented an occult lung neoplasm. The patient underwent palliative ray resection followed by the initiation of palliative chemotherapy for the primary carcinoma. A brief review of literature regarding acrometastases is provided and the potential benefit of early positron emission tomography scanning is discussed.     

Incidental thyroid carcinoma identified by positron emission tomography scanning obtained for metastatic evaluation.

Positron emission tomography (PET) scanning is an emerging technology with substantial implications for patients with solid tumors. PET is useful in identifying sites of metastatic disease as well as primary malignancy and evaluating suspicious findings found via other imaging modalities. PET is becoming a standard modality for metastatic evaluation of a variety of malignancies. However, this imaging is not limited by histology and may reveal clinically occult second lesions. We present five cases of a clinically occult thyroid cancer found in patients who underwent PET scanning for metastatic evaluations. The principal diagnoses included two patients with malignant melanoma, one each with gastric, rectal, and colonic adenocarcinoma. None of the cases had findings on physical examination. Increased uptake in the region of the thyroid was evident on the PET scan, and fine-needle aspiration biopsy indicated papillary carcinoma of the thyroid in all five cases. Although evaluation of metastatic disease is the primary purpose for PET in this setting the discovery of occult thyroid malignancy is an additional benefit of such imaging. This emphasizes the importance of investigating suspicious areas found by PET and not simply assuming that these are all sites of metastatic disease. Furthermore incidental findings of uptake in the region of the thyroid make consideration of a primary carcinoma mandatory.     

Oncogenic osteomalacia: exact tumor localization by co-registration of positron emission and computed tomography.

In oncogenic osteomalacia, the causative tumor is almost always difficult to find. A novel diagnostic approach is presented that facilitates a precise and rapid localization of the associated lesion by PET-CT co-registration using the radiotracer (68)Ga-DOTANOC. INTRODUCTION: Oncogenic osteomalacia (OOM) is an uncommon disorder characterized by hyperphosphaturia, hypophosphatemia, decreased vitamin D(3) serum levels, and osteomalacia. The paraneoplastic syndrome is exclusively driven by a small somatostatin receptor (sst)-positive tumor that produces phosphatonins, proteins that cause renal phosphate loss. OOM can be cured completely on tumor removal. However, the exact tumor localization is the most challenging step, because the lesion is notoriously difficult to detect by common imaging techniques. MATERIALS AND METHODS: A 60-year-old woman complained of severe pain in her back and chest wall, muscle weakness, and reduced physical activity for >1 year. She suffered a metatarsal fracture and presented with hyperphosphaturia and hypophosphatemia. OOM was suspected, and a meticulous search for the tumor was initiated by conventional imaging techniques, sst-mediated imaging using (111)In-octreotide scintigraphy, and (68)Ga-DOTANOC-based positron emission tomography (PET)-CT co-registration. (68)Ga-DOTANOC is a novel radiopharmaceutical compound in which the somatostatin analog octreotide is modified at position 3, chelated with DOTA, and complexed with (68)Gallium. (68)Ga-DOTANOC has an improved affinity to sst2 and sst5 relative to other radiopeptides. RESULTS: Whereas common imaging techniques such as CT failed to localize the tumor, (111)In-octreotide scintigraphy was able to detect the lesion, but only PET-CT using (68)Ga-DOTANOC revealed the exact tumor localization in the right femoral head. On tumor resection, the well being of the patient improved significantly, and biochemical parameters returned to normal. CONCLUSIONS: (68)Ga-DOTANOC-based PET-CT is a novel and powerful approach to detect sst-positive tumors in a timely manner and to provide highly resolved images facilitating the development of a therapeutic strategy.     

Mapping human somatosensory cortex with positron emission tomography

Positron emission tomography measurements of regional cerebral blood flow were used to detect focal neuronal activation in the first somatosensory cortex (SI) of humans induced by cutaneous vibratory stimulation. Intravenously administered water labeled with oxygen-15 (H2(15)O) was used as a blood flow tracer to obtain five stimulated-state and two resting-state blood flow images in each of eight normal volunteers. Three cutaneous surfaces were tested: lips, fingers, and toes. Intense, highly focal SI responses were seen during all 39 stimulated-state trials. The SI responses from the three stimulation sites were anatomically distinct and formed a medial-to-lateral homonculus in every subject. Response magnitudes (increase in local blood flow) and response locales (expressed as proportionately measured bicommissural stereotaxic coordinates) were highly consistent among subjects and on repeated trials for each subject. These findings suggest that eliciting cerebral blood flow responses by cutaneous vibration provides a safe, rapid, and reproducible tool for locating and assessing the functional status of somatosensory cortex, and offers potential clinical and research utility. This study has established normative values for future applications of this experimental paradigm.     

Functional evaluation of microvascular free flaps with positron emission tomography.

BACKGROUND: The aim of this study was to assess blood flow (BF) of microvascular free flaps studied with positron emission tomography (PET) in patients with head and neck squamous cell cancer (HNSCC) undergoing major radical surgery 3-4 weeks after high-dose radiotherapy. METHODS: Five patients underwent resection of the HNSCC of the oral cavity followed by microvascular reconstruction with a radial forearm flap. Regional BF in oral and neck tissues was measured with PET using radiolabelled water ([15O]H2O) twice (1-2 and 12-14 days, respectively) following radical surgery. RESULTS: In the first postoperative PET study, the median BF in the cutaneous flap area was 5.1 mL/100 g/min, and in the muscle contra-lateral to the recipient site 19.9 mL/100 g/min. A low flap-to-muscle BF ratio appeared to correlate with circulatory incongruity, and thus with poorer flap success. The follow-up study on the second postoperative week supported the results of the primary PET scan. CONCLUSIONS: This pilot study suggests that PET using [15O]H2O is a feasible method to quantitatively evaluate BF of the whole free flap in patients operated on for oral     

Stereotactic imaging for radiosurgery: localization accuracy of magnetic resonance imaging and positron emission tomography compared with computed tomography

Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) provide complementary information for treatment planning in stereotactic radiosurgery. We evaluated the localization accuracy of MRI and PET compared with CT. Two kinds of phantoms applicable to the Leksell G stereotactic skull frame (Elekta, Tokyo) were developed. Deviations of measured coordinates at target points (x = 50, 100, 150; y = 50, 100, 150) were determined on different axial planes (z = 30-140 for MRI and CT study and Z = 50-120 for PET and CT study). For MRI, the deviations were no more than 0.8 mm in each direction. For PET, the deviations were no more than 2.7 mm. For both imaging modalities studied, accuracy was at or below the imaging resolution (pixel size) and should be considered useful for clinical stereotactic planning purposes.     

Functional brain mapping using positron emission tomography scanning in preoperative neurosurgical planning for pediatric brain tumors.

OBJECT: The purpose of this report is to demonstrate the value of functional brain mapping using the positron emission tomography (PET) method for preoperative neurosurgical planning in children with brain tumors. Brain maps were used to characterize the relationship between potentially resectable tumors and functionally eloquent brain areas. METHODS: Five children, ranging in age from 3 to 13 years, with hemispheric brain tumors adjacent to eloquent cortex were studied. Magnetic resonance (MR) imaging was used to identify the brain tumors; PET imaging after injection of [18F] fluorodeoxyglucose (FDG), [11C]L-methionine (CMET), or a combination of the two was performed to grade the tumors; and a [15O] H2O uptake study was used to characterize the anatomical relationships of the tumors to functional cortex. The cortical activation maps were obtained during control periods and during behavioral tasks and were used to document motor, visual, and speech and language organizational areas. Wada tests were performed in two patients. Language and speech activation was concordant with the results of Wada testing. CONCLUSIONS: Functional brain mapping using PET scans and coregistered MR images provided the neurosurgeon with precise definitions of structural and functional cortical areas; this altered surgical management in some cases and/or was used to predict outcome. The combination of PET imaging with FDG and/or CMET and measurements of [15O] water uptake was useful in characterizing and grading tumors and instrumental in achieving effective neurosurgical planning. Postoperative results in the five cases suggest that preoperative functional brain mapping has the potential to improve outcome by defining a surgical plan to maximize resection and minimize the risk of neurological sequelae.     

Localization of somatosensory function by using positron emission tomography scanning: a comparison with intraoperative cortical stimulation

OBJECT: To investigate the utility of [15O]H2O positron emission tomography (PET) activation studies in the presurgical mapping of primary somatosensory cortex, the authors compared the magnitude and location of activation foci obtained using PET scanning with the results of intraoperative cortical stimulation (ICS). METHODS: The authors used PET scanning and vibrotactile stimulation (of the face, hand, or foot) to localize the primary somatosensory cortex before surgical resection of mass lesions or epileptogenic foci affecting the central area in 20 patients. With the aid of image-guided surgical systems, the locations of significant activation foci on PET scanning were compared with those of positive ICS performed at craniotomy after the patient had received a local anesthetic agent. In addition, the relationship between the magnitude and statistical significance of blood flow changes and the presence of positive ICS was examined. In 22 (95.6%) of 23 statistically significant (p < 0.05) PET activation foci, spatially concordant sites on ICS were also observed. Intraoperative cortical stimulation was positive in 40% of the PET activation studies that did not result in statistically significant activation. In the patients showing these results, there was a clearly identifiable t-statistic peak that was spatially concordant with the site of positive ICS in the sensorimotor area. All PET activation foci with a t statistic greater than 4.75 were associated with spatially concordant sites of positive ICS. All PET activation foci with a t statistic less than 3.2 were associated with negative ICS. CONCLUSIONS: Positron emission tomography is an accurate method for mapping the primary somatosensory cortex before surgery. The need for ICS, which requires local anesthesia, may be eliminated when PET foci with high (> 4.75) or low (< 3.20) t-statistic peaks are elicited by vibrotactile stimulation.     

Visual activation positron emission tomography for presurgical evaluation of occipital lobe epilepsy--case report

A 14-year-old boy suffered from daily epileptic seizures originating from the left polymicrogyric occipital cortex. Visual activation positron emission tomography (PET) was used to map the function of the occipital cortex presurgically. Loss of visual function in the left occipital cortex was suggested by both visual activation PET and electrical cortical stimulation. Left occipital lobectomy resulted in a completely seizure-free status without deterioration in the visual function. Preoperative evaluation of the visual function in the epileptogenic occipital cortex by activation studies using PET or functional magnetic resonance imaging is the key to the successful surgical treatment of occipital lobe epilepsy.     

Imaging bone microdamage in vivo with positron emission tomography

Microdamage accumulation in bone is now considered a contributing cause for bone fragility in older women. However, there is still no method to detect and quantify microdamage in vivo. We have found that positron emission tomography (PET) may be useful to detect and quantify bone microdamage in vivo using a high-resolution PET scanner with [¹⁸F]NaF as the tracer. We have done several experiments using the rat ulnar loading model that demonstrate that (1) high-resolution [¹⁸F]NaF PET can detect newly created microdamage in vivo; (2) the microdamage detected in this way is co-localized with damage detected by histological and autoradiographic procedures; and (3) high-resolution [¹⁸F]NaF PET can distinguish between the effects of mechanical loading that does not produce damage and fatigue loading that creates microdamage. The high-resolution [¹⁸F]NaF PET shows promise as a non-invasive means to image bone microdamage.     

Imaging bone microdamage in vivo with positron emission tomography

Microdamage accumulation in bone is now considered a contributing cause for bone fragility in older women. However, there is still no method to detect and quantify microdamage in vivo. We have found that positron emission tomography (PET) may be useful to detect and quantify bone microdamage in vivo using a high-resolution PET scanner with [¹⁸F]NaF as the tracer. We have done several experiments using the rat ulnar loading model that demonstrate that (1) high-resolution [¹⁸F]NaF PET can detect newly created microdamage in vivo; (2) the microdamage detected in this way is co-localized with damage detected by histological and autoradiographic procedures; and (3) high-resolution [¹⁸F]NaF PET can distinguish between the effects of mechanical loading that does not produce damage and fatigue loading that creates microdamage. The high-resolution [¹⁸F]NaF PET shows promise as a non-invasive means to image bone microdamage.     

11C-choline positron emission tomography/computerized tomography for tumor localization of primary prostate cancer in comparison with 12-core biopsy

PURPOSE: (11)C-choline positron emission tomography is an innovative imaging technique for prostate cancer. We assessed the sensitivity of positron emission tomography used together with computerized tomography for intraprostatic localization of primary prostate cancer on a nodule-by-nodule basis, and compared its performance with 12-core transrectal biopsy. MATERIALS AND METHODS: In 43 patients with known prostate cancer who had received positron emission tomography/computerized tomography before initial biopsy, we assessed sensitivity of positron emission tomography/computerized tomography for localization of nodules 5 mm or greater (those theoretically large enough for visualization) using radical prostatectomy histopathology as the reference standard. Comparison with transrectal ultrasound guided biopsy was based on sextant assessment of all cancer foci following sextant-by-sextant matching and reconstruction. Sensitivity/specificity of positron emission tomography/computerized tomography and magnetic resonance imaging for prediction of extraprostatic extension was also assessed. RESULTS: Positron emission tomography/computerized tomography showed 83% sensitivity for localization of nodules 5 mm or greater. At logistic regression analysis only nodule size appeared to influence sensitivity. At sextant assessment positron emission tomography/computerized tomography had slightly better sensitivity than transrectal ultrasound guided biopsy (66% vs 61%, p = 0.434) but was less specific (84% vs 97%, p = 0.008). For assessment of extraprostatic extension, sensitivity of PET/CT was low in comparison with magnetic resonance imaging (22% vs 63%, p <0.001). CONCLUSIONS: Positron emission tomography/computerized tomography has good sensitivity for intraprostatic localization of primary prostate cancer nodules 5 mm or greater. Positron emission tomography/computerized tomography and transrectal ultrasound guided biopsy show similar sensitivity for localization of any cancer focus. Positron emission tomography/computerized tomography does not seem to have any role in extraprostatic extension detection. Studies of diagnostic accuracy (as opposed to tumor localization) are needed in patients with suspected prostate cancer to see whether positron emission tomography/computerized tomography could have a role in not selected patients.