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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dual-modality imaging is an in vivo diagnostic technique that obtains structural and functional information directly from patient studies in a way that cannot be achieved with separate imaging systems alone. Dual-modality imaging systems are configured by combining computed tomography (CT) with radionuclide imaging (using positron emission tomography (PET) or single-photon emission computed tomography (SPECT)) on a single gantry which allows both functional and structural imaging to be performed during a single imaging session without having the patient leave the imaging system. A SPECT/CT system developed at UCSF is being used in a study to determine if dual-modality imaging offers advantages for assessment of patients with prostate cancer using (111)In-ProstaScint, a radiolabeled antibody for the prostate-specific membrane antigen. (111)In-ProstaScint images are reconstructed using an iterative maximum-likelihood expectation-maximization (ML-EM) algorithm with correction for photon attenuation using a patient-specific map of attenuation coefficients derived from CT. The ML-EM algorithm accounts for the dual-photon nature of the 111In-labeled radionuclide, and incorporates correction for the geometric response of the radionuclide collimator. The radionuclide image then can be coregistered and overlaid in color on a grayscale CT image for improved localization of the functional information from SPECT. Radionuclide images obtained with SPECT/CT and reconstructed using ML-EM with correction for photon attenuation and collimator response improve image quality in comparison to conventional radionuclide images obtained with filtered backprojection reconstruction. These results illustrate the potential advantages of dual-modality imaging for improving the quality and the localization of radionuclide uptake for staging disease, planning treatment, and monitoring therapeutic response in patients with cancer.
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PMID:Dual-modality imaging of cancer with SPECT/CT. 1262 72

At this time there is no highly sensitive and specific widespread radiographic test for local staging of prostate cancer. Future developments will likely require a combination of imaging modalities with utilization guided by risk-stratification models (Table 4). Staging data for all imaging tests discussed in this article are summarized in Tables 5 and 6. Clinically, conventional gray-scale TRUS remains the most frequently used tool because of its utility in guiding prostatic biopsies. Modifications of TRUS--including power and color Doppler, 3D imaging, and new ultrasound contrast agents and elastography--show promise in increasing the accuracy of ultrasound. Endorectal MRI may have some value for staging selected patients. The addition of prostatic MRS, which images the differential activity of metabolites, may increase the specificity of MRI. Newer techniques with finer voxel resolution may prove to be clinically useful. A large well-designed study evaluating the utility of MRI/MRS is currently being planned. Cross-sectional imaging of the pelvis with either MRI or CT should be used selectively as should radionuclide bone scans. Similarly, ProstaScint scans should be ordered selectively, either before or after primary therapy, rather than routinely in all patients.
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PMID:Imaging clinically localized prostate cancer. 1273 4

ProstaScint (CYT-356 or capromab pendetide, Cytogen) is an 111In-labeled monoclonal mouse antibody specific for prostate-specific membrane antigen, a prostate transmembrane glycoprotein that is upregulated in prostate adenocarcinoma. ProstaScint scans are US Food and Drug Administration approved for pretreatment evaluation of metastatic disease in high-risk patients. They are also approved for post-prostatectomy assessment of recurrent disease in patients with a rising prostate-specific antigen level. This review explores the literature on ProstaScint and its use in guiding the treatment of prostate cancer. A novel technique for identifying areas of cancer within the prostate using ProstaScint images fused with pelvic computed tomography scans is also described. The identification of areas of high antibody signal provides targets for radiotherapeutic dose escalation, with the overall goals of improving treatment outcome while preserving adjacent tissue structures and decreasing treatment morbidity.
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PMID:Role of ProstaScint for brachytherapy in localized prostate adenocarcinoma. 1522 91

Prostate cancer is the most common malignant disease and second in causes of cancer death among men in Western Europe and North America. Despite improved surgical and irradiation techniques tumor relapse after curatively intended therapy is not uncommon. Due to the difficulty in discriminating local and systemic progression, it is often difficult to decide what this means for the patient and what kind of second-line treatment has to be given. Modern imaging techniques (MRI with endorectal coil, Choline-PET-CT, ProstaScint-Scan) are used for diagnosis of prostate cancer relapse. Nevertheless, early detection of local tumor relapse and likewise the detection of disseminated tumor cells often fails. To differentiate between local and systemic progression, prognostic factors of the primary tumor (grading, surgical margins, infiltration of the seminal vesicles, lymph node metastases) and PSA kinetics are used. The time from initial treatment to biochemical relapse and PSA doubling time are of highest prognostic relevance. Local progression allows second-line local treatment with potentially curative results (local irradiation after radical prostatectomy, salvage-surgery / cryotherapy / HIFU after irradiation), while in the case of systemic progress a palliative systemic therapy (hormonal treatment, chemotherapy, bisphosphonates) is indicated. Before deciding on the most appropriate therapy, prognostic factors and the patient's individual situation (co-morbidity, life expectancy, individual wishes) should be taken into account.
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PMID:Prostate cancer relapse after therapy with curative intention: a diagnostic and therapeutic dilemma. 1593 26

During the last decade, there has been a significant advancement in imaging of urologic diseases. Transrectal ultrasound (TRUS), computerized tomography (CT), magnetic resonance imaging (MRI), magnetic resonance spectroscopy (MRS), and positron emission tomography (PET) are still experiencing new developments in urology. Despite these many technological advances, the initial diagnostic procedure for a patient with suspected prostate cancer (PC) is multiple site blind prostate biopsies. There is a need for a noninvasive metabolic imaging modality to direct the site of biopsy to decrease the sampling error. MRS seems promising but as it is a costly and more time-consuming test, further studies are needed to evaluate its clinical utility. Currently, PET does not play any role to direct biopsy. Acetate and choline appear to be better tracers than FDG for the detection of a prostate lesion, however, further well-organized studies are needed before any of these agents can be used clinically. Incidental detection of intense focal uptake in the prostate during whole body PET scanning should be evaluated with prostate-specific antigen (PSA) and TRUS-guided biopsy. Although FDG is inferior to other tracers for primary staging, it may be useful in selected patients with suspected high-grade cancer. The role of ProstaScint scan is still controversial for detection of recurrent PC. This study may be helpful for evaluating nodal metastases when PSA is elevated and bone scan is negative. Bone scan remains the study of choice when bone metastases are suspected (PSA>15-20 ng/mL+/-bone pain). Acetate and choline provide better accuracy than FDG in the detection of local soft tissue disease, nodal involvement, and distant metastases. High FDG uptake may be indicative of more aggressive and possibly androgen-independent disease. PET/CT with any of the above PET tracers will most likely be preferred to the PET scan alone due to better localization of a hot lesion in PET/CT. Nuclear medicine studies also have been used to evaluate acute scrotum and testicular neoplasms. Scrotal scintigraphy has lost its popularity to Doppler ultrasound in the evaluation of the acute scrotum. In testicular tumors, FDG-PET appears to be superior to conventional imaging modalities in initial staging, detection of residual/recurrence, and monitoring treatment response. Tumor markers after treatment occasionally are elevated and cannot locate the site of recurrence, FDG-PET can play a very important role in this regard. Nuclear medicine studies also have been used to evaluate diseases of the urinary bladder. Radionuclide cystography is more sensitive and has less than 1/20 the radiation exposure of the conventional contrast enhanced micturating cystourethrogram (MCU). However, the utility of FDG-PET in the evaluation of bladder cancer seems to be limited to the evaluation of distant metastases. 11C-Methionine and choline may be a better option for local and nodal disease due to their negligible excretion in the urine.
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PMID:Nuclear medicine studies of the prostate, testes, and bladder. 1635 96

Prostate cancer is the most common type of cancer (other than skin cancer) among men in the United States. Although prostate cancer is one of the few cancers that grow so slowly that it may never threaten the lives of some patients, it can be lethal once metastasized. Indium-111 capromab pendetide (ProstaScint, Cytogen Corporation, Princeton, NJ) imaging is indicated for staging and recurrence detection of the disease, and is particularly useful to determine whether or not the disease has spread to distant metastatic sites. However, the interpretation of 111In-capromab pendetide is challenging without correlated structural information mostly because the radiopharmaceutical demonstrates nonspecific uptake in the normal vasculature, bowel, bone marrow, and the prostate gland. We developed an improved method of imaging and localizing 111In-Capromab pendetide using a SPECT/CT imaging system. The specific goals included: i) development and application of a novel iterative SPECT reconstruction algorithm that utilizes a priori information from coregistered CT; and ii) assessment of clinical impact of adding SPECT/CT for prostate cancer imaging with capromab pendetide utilizing the standard and novel reconstruction techniques. Patient imaging studies with capromab pendetide were performed from 1999 to 2004 using two different SPECT/CT scanners, a prototype SPECT/CT system and a commercial SPECT/CT system (Discovery VH, GE Healthcare, Waukesha, WI). SPECT projection data from both systems were reconstructed using an experimental iterative algorithm that compensates for both photon attenuation and collimator blurring. In addition, the data obtained from the commercial system were reconstructed with attenuation correction using an OSEM reconstruction supplied by the camera manufacturer for routine clinical interpretation. For 12 sets of patient data, SPECT images reconstructed using the experimental algorithm were interpreted separately and compared with interpretation of images obtained using the standard reconstruction technique. The experimental reconstruction algorithm improved spatial resolution, reduced streak artifacts, and yielded a better correlation with anatomic details of CT in comparison to conventional reconstruction methods (e.g., filtered back-projection or OSEM with attenuation correction only). Images produced with the experimental algorithm produced a subjective improvement in the confidence of interpretation for 11 of 12 studies. There were also changes in interpretations for 4 of 12 studies although the changes were not sufficient to alter prognosis or the patient treatment plan.
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PMID:Progress in SPECT/CT imaging of prostate cancer. 1686 63

Efforts to evaluate and discover diagnostic and therapeutic markers for prostate cancer continue. One of these, prostate-specific membrane antigen (PSMA), a transmembrane protein expressed in all types of prostatic tissue, remains a useful diagnostic and possibly therapeutic target. The radio-immunoconjugate form of the anti-PSMA monoclonal antibody 7E11 is used in the commercially available and US Food and Drug Administration-approved diagnostic tool, the ProstaScint(R) (Cytogen Corporation, Princeton, NJ) scan. Recent studies have demonstrated other possible useful roles for PSMA as a target, not only in prostate cancer, but in other malignancies.
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PMID:Overview of prostate-specific membrane antigen. 1698 27

Indium In 111 capromab pendetide (ProstaScint(R); Cytogen Corporation, Princeton, NJ), a radiolabeled monoclonal antibody to prostate-specific membrane antigen, offers a potential means of localizing sites of soft tissue metastasis in prostate cancer patients. Although the test was previously limited by poor positive predictive value and specificity owing to the inherent limitations of single photon emission computed tomography, improvements in techniques of anatomic localization, along with increased reader experience, have significantly improved its accuracy. In addition to the conventional roles for ProstaScint, such as staging and detection of relapse, a number of new potential applications have emerged.
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PMID:ProstaScint(R) Scan: Contemporary Use in Clinical Practice. 1698 28

The rationale on which positron emission tomography/computed tomography (PET/CT) imaging is based, combining the functional features of PET with the anatomic detail of CT, provides many advantages that are easily transferable to single-photon emission computed tomography (SPECT)/CT imaging. Our efforts have focused on applying fused SPECT/CT imaging to identify prostate cancer and its metastasis and recurrence through radioimmunoscintigraphy (RIS). This application of RIS to imaging prostate cancer requires 2 key components: (1) a well-defined target associated with the cancer and (2) a "magic bullet" to seek that target. A well-characterized RIS target for prostate cancer is prostate-specific membrane antigen, or PSMA, and finding the bullet to seek this target with high sensitivity and specificity has been the focus of intensive study for nearly two decades. One of the candidate bullets developed is capromab pendetide, which is a monoclonal antibody that seeks PSMA. This antibody is commercially available as ProstaScint, which can be labeled with indium-111 to localize prostate cancer via SPECT imaging. In the course of applying fused SPECT/CT ProstaScint imaging to more than 800 prostate cancer cases, numerous refinements to our protocol have evolved that are aimed at staging the cancer with utmost accuracy. In addition to optimizing the localization of prostate cancer and its metastasis, these refinements also have been extended toward guiding both the implantation of radioactive seeds in brachytherapy and in other types of radiation therapy which is illustrated through 5 case reports. Progress in the therapeutic targeting of PSMA is also being actively explored, which has more universal ramifications because PSMA is found in the neovasculature of other types of cancers.
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PMID:Synergistic value of single-photon emission computed tomography/computed tomography fusion to radioimmunoscintigraphic imaging of prostate cancer. 1716 Oct 36

Cancer of the prostate is the most common cancer in males accounting for 33% of newly diagnosed cases. It is the second leading cause of cancer death in American males. The prevalence of prostate cancer increases most rapidly with age and the incidence (unlike other cancers) continues to rise with advancing age. Death due to this cancer is almost invariably the result of failure to control metastatic disease. In addition, several studies have demonstrated that over 30% of patients will experience biochemical recurrence after surgery with long-term (more than 10 years) follow-up. Information regarding the location of the cancer is critical to the success of initial therapy when deciding between local versus systemic treatment options in the newly diagnosed patient. For patients who have already undergone definitive treatment, the localization of recurrent tumor, evidenced by an elevation of prostate-specific antigen, is difficult unless the tumor burden is large enough to be detected on conventional radiographic studies or digital rectal examination and prostatic fossa biopsy. ProstaScint is a diagnostic tool used to detect metastatic prostate cancer in lymph nodes or other sites. This article provides an overview on the uses of ProstaScint in the assessment of patients with recurrent or metastatic prostate cancer.
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PMID:ProstaScint and its role in the diagnosis of prostate cancer. 1762 43


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