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Quantitative Accuracy and Lesion Detectability of Low-Dose FDG-PET for Lung Cancer Screening.

Quantitative Accuracy and Lesion Detectability of Low-Dose FDG-PET for Lung Cancer Screening.

J Nucl Med. 2016 Sep 29;

Authors: Schaefferkoetter JD, Yan J, Soderlund TA, Townsend DW, Conti M, Tam JK, Soo R, Tham I

Abstract
Lung cancer remains responsible for more deaths worldwide than any other cancer, but recently there has been a significant shift in the clinical paradigm regarding the initial management of subjects at high risk for this disease. Low dose computed tomography (CT) has demonstrated significant improvements over planar X-ray screening for patient prognoses and is now performed in the U.S. Specificity of this modality, however, is poor and the additional information from positron emission tomorgraphy (PET) has the potential to improve its accuracy. Routine screening requires consideration of the effective dose delivered to the patient, and this work investigates image quality of PET for low-dose conditions, in the context of lung lesion detectability. Reduced radiotracer doses were simulated by randomly discarding counts from clinical lung cancer scans acquired in list-mode. Bias and reproducibility of lesion activity values were relatively stable even at low total counts of around 5 million trues. Additionally, numerical observer models were developed and trained with the results of 2 physicians and 3 postdoctoral researchers with PET experience in a detection task; detection sensitivity of the observers was well correlated with lesion signal-to-noise ratio (SNR). The models were used prospectively to survey detectability of lung cancer lesions, and the findings suggested a lower limit around 10 million true counts for maximizing performance. Under the acquisition parameters used in this study, this translates to an effective patient dose less than 0.4 mSv, potentially allowing a complete low dose PET/CT lung screening scan to be performed under 1 mSv.

PMID: 27688481 [PubMed - as supplied by publisher]




Associations between somatic mutations and metabolic imaging phenotypes in non-small cell lung cancer.

Associations between somatic mutations and metabolic imaging phenotypes in non-small cell lung cancer.

J Nucl Med. 2016 Sep 29;

Authors: Yip SS, Kim J, Coroller T, Parmar C, Rios Velazquez E, Huynh E, Mak R, Aerts HJ

Abstract
PURPOSE: Positron emission tomography (PET)-based radiomics has been used to non-invasively quantify the metabolic tumor phenotypes; however, little is known about the relationship between these phenotypes and underlying somatic mutations. This study assessed the association and predictive power of (18)F-FDG-PET-based radiomic features for somatic mutations in non-small cell lung cancer (NSCLC) patients.
METHODS: 348 NSCLC patients underwent diagnostic (18)F-FDG-PET/CT scans and were tested for genetic mutations. 13% (44/348) and 28% (96/348) of patients were found to harbor an EGFR (EGFR+) or KRAS (KRAS+) mutation, respectively. We evaluated 21 imaging features: 19 independent radiomic features quantifying phenotypic traits and 2 conventional features (metabolic tumor volume (MTV) and maximum standard uptake value (SUVmax)). The association between imaging features and mutation status (e.g. EGFR+ vs. EGFR-) was assessed using the Wilcoxon rank-sum test. The ability of each imaging feature to predict mutation status was evaluated by the area under the receiver operating curve (AUC) and its significance was compared to a random guess (AUC=0.5) using the Noether's test. All p-values were corrected for multiple hypothesis testing by controlling the false discovery rate (FDRWilcoxon, FDRNoether) with a significance threshold of 10%.
RESULTS: Eight radiomic features and both conventional features were significantly associated with EGFR mutation status (FDRWilcoxon=0.01-0.10). One radiomic feature (normalized inverse difference moment) outperformed all other features in predicting EGFR mutation status (EGFR+ vs EGFR-, AUC=0.67, FDRNoether=0.0032), as well as differentiating between KRAS+ and EGFR+ (AUC=0.65, FDRnoether=0.05). None of the features were associated with or predictive of KRAS mutation status (KRAS+ vs. KRAS-, AUC=0.50-0.54).
CONCLUSION: Our results indicate that EGFR mutations may drive different metabolic tumor phenotypes that are captured in PET images, whereas KRAS mutated tumors do not. This proof-of-concept study sheds light on genotype-phenotype interactions, using radiomics to capture and describe the phenotype, and may have potential for developing non-invasive imaging biomarkers for somatic mutations.

PMID: 27688480 [PubMed - as supplied by publisher]




18F-FDG PET in Posterior Cortical Atrophy and Dementia with Lewy Bodies.

18F-FDG PET in Posterior Cortical Atrophy and Dementia with Lewy Bodies.

J Nucl Med. 2016 Sep 29;

Authors: Whitwell J, Graff-Radford J, Singh T, Drubach D, Senjem M, Spychalla A, Tosakulwong N, Lowe VJ, Josephs K

Abstract
Posterior cortical atrophy (PCA) and Dementia with Lewy bodies (DLB) have both been associated with occipital lobe hypometabolism on (18)F fluorodeoxyglucose (FDG) positron emission tomography (PET), while relative sparing of posterior cingulate metabolism compared to precuneus/cuneus (i.e. cingulate island sign) is a feature of DLB. We aimed to determine whether patterns of hypometabolism or the cingulate island sign differed between PCA and DLB.
METHODS: Sixteen clinically diagnosed PCA and 13 probable DLB subjects underwent (18)F-FDG PET. All PCA subjects showed beta-amyloid deposition on PET scanning. Regional hypometabolism was assessed compared to a control cohort (n = 29) using voxel and region-level analyses in Statistical Parametric Mapping. A ratio of metabolism in the posterior cingulate to precuneus plus cuneus was calculated to assess the cingulate island sign. In addition, a visual assessment of the (18)F-FDG PET scans was performed to determine whether the cingulate island sign was present in each subject.
RESULTS: PCA and DLB showed overlapping patterns of hypometabolism involving lateral occipital lobe, lingual gyrus, cuneus, precuneus, posterior cingulate, inferior parietal lobe, supramarginal gyrus, striatum and thalamus. However, DLB showed greater hypometabolism in medial occipital lobe, orbitofrontal cortex, anterior temporal lobe and caudate nucleus than PCA and PCA showed more asymmetric patterns of hypometabolism than DLB. The cingulate island sign was present in both DLB and PCA, although was more asymmetric in PCA.
CONCLUSION: Regional hypometabolism overlaps to a large degree between PCA and DLB, although the degree of involvement of the frontal and anterior temporal lobes, and the presence of asymmetry could be useful in differential diagnosis.

PMID: 27688479 [PubMed - as supplied by publisher]




Hybrid surgical guidance: Does hardware integration of gamma- and fluorescence- imaging modalities make sense?

Hybrid surgical guidance: Does hardware integration of gamma- and fluorescence- imaging modalities make sense?

J Nucl Med. 2016 Sep 29;

Authors: KleinJan GH, Hellingman D, van den Berg NS, van Oosterom MN, Hendricksen K, Horenblas S, Valdés Olmos RA, van Leeuwen FW

Abstract
INTRODUCTION: The clinically applied hybrid tracer indocyanine green (ICG)-(99m)Tc-nanocolloid enables combined radio- and fluorescence image guidance during sentinel node (SN) biopsy procedures. In order to provide optimal surgical guidance this tracer requires the presence of both gamma and fluorescence modalities in the operating room. We reasoned that combination and/or integration of these modalities could further evolve the hybrid surgical guidance concept. To study this potential we clinically applied two set-ups that included the combination of gamma detection modalities and an open surgery fluorescence camera.
METHODS: To attach the fluorescence camera (VITOM) to either 1) a gamma-ray detection probe (GP; VITOM-GP) or 2) a portable gamma camera (GC) (VITOM-GC), clip-on brackets were designed and 3D-printed in sterilizable RC31. Both combined modalities were evaluated in respectively five and six patients with penile cancer during a SN biopsy procedure using ICG-(99m)Tc-nanocolloid. Intraoperatively, radio- and fluorescence guided SN detection rates were scored at working distances of 0, 10, 20, and 30 cm for both combinations.
RESULTS: Using the VITOM-GP combination 9 SNs were evaluated. Gamma tracing rates were shown to be 100, 88.9, 55.6 and 55.6 % at a respective working distance of 0, 10, 20 and 30 cm. Detection rates for the fluorescence imaging-based detection were found to be 100, 77.8 and 77.8 %, at respective working distances of 10, 20, and 30 cm. Using the VITOM-GC set-up, all 10 intraoperatively evaluated SNs could be visualized with the gamma camera independent of the working distance. Fluorescence detection rates were 90, 80 and 80% at 10, 20 and 30cm working distance. The integrated detection modalities were shown to work synergistically; overall the GC was most valuable for rough localization (10-30 cm range) of the SNs, the GP for providing convenient real-time acoustic feedback, while fluorescence guidance allowed detailed real-time SN visualization.
CONCLUSION: Our findings suggest that full integration of a fluorescence camera with gamma detector (GP or GC) can be of value when a hybrid, radioactive and fluorescent, tracer is used.

PMID: 27688478 [PubMed - as supplied by publisher]




Cure of human ovarian carcinoma solid xenografts by fractionated [211At] alpha-radioimmunotherapy: Influence of tumor absorbed dose and effect on long-term survival.

Cure of human ovarian carcinoma solid xenografts by fractionated [211At] alpha-radioimmunotherapy: Influence of tumor absorbed dose and effect on long-term survival.

J Nucl Med. 2016 Sep 29;

Authors: Bäck TA, Chouin N, Lindegren S, Kahu H, Jensen H, Albertsson P, Palm S

Abstract
The goal of this study was to investigate if targeted alpha therapy (TAT) could be used to successfully treat also macro tumors, in addition to its established role for treating micrometastatic and minimal disease. We used an intravenous (i.v.) fractionated regimen of alpha-radioimmunotherapy (α-RIT) in a subcutaneous (s.c.) tumor model in mice. We aimed at evaluating the absorbed dose levels required for tumor eradication and to monitor tumor growth, as well as the long-term survival after treatment.
METHODS: Mice bearing s.c.-tumors (50 mm3, NIH:OVCAR-3) were i.v.-injected repeatedly (1 to 3 injections, 7-10 days apart allowing bone-marrow recovery) with (211)At-MX35-F(ab')2 at different activities (close to acute myelotoxicity). Mean absorbed dose to tumors and organs were estimated from biodistribution data and summed for the fractions. Tumor growth was monitored for 100 days and survival for 1 year after treatment. Toxicity analysis included body weight, WBC and hematocrit.
RESULTS: Effects on tumor growth following fractionated α-RIT with (211)At-MX35-F(ab')2 was strong and dose-dependent. Complete remission (TFF=100%) was found for tumor doses of 12.4 and 16.4 Gy. The administered activities were high and long-term toxicity effects (up to 60 weeks) were clear. Above 1 MBq, the median survival decreased linearly with injected activity, from 44 to 11 weeks. Toxicity was also seen by reduced body weight. WBC-analysis after α-RIT indicated bone marrow recovery for the low activity groups, while for high activity groups the reduction was close to acute myelotoxicity. A decrease in hematocrit was seen at a late interval (34-59 weeks after therapy). The main external indication of poor health was dehydration.
CONCLUSION: Having observed complete eradication of solid tumor xenografts, we conclude that TAT regimens could stretch beyond the realm of micrometastatic disease and be eradicative also for macro tumors. Our observations indicated that at least 10 Gy is required. This was in good agreement with the calculated TCP. Considering a RBE of 5, this dose level seemed reasonable. However, complete remission was achieved first at activity levels close-to lethal and was accompanied with biological effects that reduced the long-term survival.

PMID: 27688477 [PubMed - as supplied by publisher]




Optimization of image reconstruction for yttrium-90 SIRT on a LYSO PET/CT system using a Bayesian penalized likelihood reconstruction algorithm.

Optimization of image reconstruction for yttrium-90 SIRT on a LYSO PET/CT system using a Bayesian penalized likelihood reconstruction algorithm.

J Nucl Med. 2016 Sep 29;

Authors: Rowley LM, Bradley KM, Boardman P, Hallam A, McGowan DR

Abstract
Imaging on a gamma camera with Yttrium-90 ((90)Y) following selective internal radiotherapy (SIRT) may allow for verification of treatment delivery but suffers relatively poor spatial resolution and imprecise dosimetry calculation. (90)Y Positron Emission Tomography (PET) / Computed Tomography (CT) imaging is possible on 3D, time-of-flight machines however images are usually poor due to low count statistics and noise. A new PET reconstruction software using a Bayesian penalized likelihood (BPL) reconstruction algorithm (termed Q.Clear) released by GE was investigated using phantom and patient scans to optimize the reconstruction for post-SIRT imaging and clarify if this leads to an improvement in clinical image quality using (90)Y.
MATERIALS AND METHODS: Phantom studies over an activity range of 0.5GBq-4.2GBq were carried out to assess the contrast recovery, background variability and contrast-to-noise ratio (CNR) for a range of BPL and Ordered Subset Expectation Maximization (OSEM) reconstructions on a GE Discovery 710 PET/CT. Patient images post-SIRT were reconstructed using the same parameters and were scored and ranked based on image quality, as assessed by visual evaluation, with the corresponding Single-Photon Emission Computed Tomography (SPECT)/CT Bremsstrahlung images by two experienced radiologists.
RESULTS: CNR was significantly better in BPL reconstructions when compared to OSEM in phantom studies. The patient-derived BPL and matching Bremsstrahlung images scored higher than OSEM reconstructions when scored by radiologists. BPL with a beta value of 4000 was ranked the highest of all images. Deadtime was apparent in the system above a total phantom activity of 3.3GBq.
CONCLUSIONS: BPL with a beta value of 4000 is the optimal image reconstruction in PET/CT for confident radiological reading when compared to other reconstruction parameters for (90)Y imaging post SIRT imaging. Activity in the field-of-view should be below 3.3GBq at the time of PET imaging to avoid deadtime losses for this scanner.

PMID: 27688476 [PubMed - as supplied by publisher]




A randomized feasibility study of 18F-fluoroestradiol positron emission tomography to predict pathological response to neoadjuvant systemic therapy in estrogen receptor-rich postmenopausal breast cancer.

A randomized feasibility study of 18F-fluoroestradiol positron emission tomography to predict pathological response to neoadjuvant systemic therapy in estrogen receptor-rich postmenopausal breast cancer.

J Nucl Med. 2016 Sep 29;

Authors: Chae SY, Kim SB, Ahn SH, Kim HO, Yoon DH, Ahn JH, Jung KH, Han S, Oh SJ, Lee SJ, Kim HJ, Son BH, Gong G, Lee HS, Moon DH

Abstract
The aim of this study was to explore the ability of (18)F-fluoroestradiol ((18)F-FES) positron emission tomography/computed tomography (PET/CT) imaging to predict pathologic response to neoadjuvant therapy in postmenopausal women with estrogen receptor (ER)-rich breast cancer.
METHODS: This was a prospective, single-center study conducted as a sub-study of the neoadjuvant study of chemotherapy versus endocrine therapy in postmenopausal patients with primary breast cancer (NEOCENT) trial. Patients with ER-rich breast cancer were randomized to neoadjuvant chemotherapy (NC) or neoadjuvant endocrine therapy (NET). Baseline maximum standardized uptake values (SUVmax) of (18)F-FES PET/CT were measured. The pathologic response was assessed by the Miller-Payne system as non-response (grades 1 and 2) and response (grades 3-5).
RESULTS: Twenty-six patients were enrolled, with pathological response achieved in 25 (NC: 12, and NET: 13). Two patients achieved pathological complete response (pCR) after NC, but the remaining 23 patients had residual disease after NC or NET. Eight of twelve patients responded to NC, and 4 of 13 to NET; the difference was marginally significant (P = 0.07). In the NC group, the two patients with (18)F-FES-negative tumors and none of the ten patients with (18)F-FES-avid tumors achieved pCR (P = 0.02). No difference in the SUVmax between responders and non-responders was observed in either group. However, five of seven NC patients with a baseline SUVmax <7.3 achieved pathologic response, while none of the five NET patients with a SUVmax <7.3 were responders (P = 0.03). The SUVmax values of the NC group were negatively correlated with percentage reduction of tumor cellularity (r = -0.63, P = 0.03), while those of the NET group showed positive correlation (r = 0.62, P = 0.02). During the median follow-up of 74 months (range: 44-85 months), recurrence occurred in only four NET patients. In patients with a SUVmax <7.3, recurrence occurred in none of the eight NC patients and two of the five NET patients (P = 0.13).
CONCLUSION: Postmenopausal women who are ER-positive, but (18)F-FES-negative, may benefit from NC rather than NET. (18)F-FES PET/CT has the potential to predict response to neoadjuvant therapy in postmenopausal women with ER-rich breast cancer.

PMID: 27688475 [PubMed - as supplied by publisher]




Fission Produced 99Mo without a Nuclear Reactor.

Fission Produced 99Mo without a Nuclear Reactor.

J Nucl Med. 2016 Sep 29;

Authors: Youker AJ, Chemerisov SD, Tkac P, Kalensky M, Heltemes TA, Rotsch DA, Vandegrift GF, Krebs JF, Makarashvili V, Stepinski DC

Abstract
Molybdenum-99, the parent of the widely used medical isotope (99m)Tc, is currently produced by irradiation of enriched uranium in nuclear reactors. The supply of this isotope is encumbered by the aging of these reactors and concerns about international transportation and nuclear proliferation.
METHODS: We report results for the production of (99)Mo from the accelerator-driven subcritical fission of an aqueous solution containing low enriched uranium. The predominately fast neutrons generated by impinging high-energy electrons onto a tantalum convertor are moderated to thermal energies to increase fission processes. The separation, recovery, and purification of (99)Mo were demonstrated at the pilot scale using a recycled uranyl sulfate solution.
RESULTS AND CONCLUSION: The (99)Mo yield and purity were found to be unaffected by reuse of the previously irradiated and processed uranyl sulfate solution. Results from a 51.8 Gbq (99)Mo production run are presented.

PMID: 27688474 [PubMed - as supplied by publisher]




Repeatability of 18F-FLT PET in a Multi-Center Study of Patients with High Grade Glioma.

Repeatability of 18F-FLT PET in a Multi-Center Study of Patients with High Grade Glioma.

J Nucl Med. 2016 Sep 29;

Authors: Lodge MA, Holdhoff M, Leal JP, Bag AK, Nabors LB, Mintz A, Lesser GJ, Mankoff DA, Desai AS, Mountz JM, Lieberman FS, Fisher JD, Desideri S, Ye X, Grossman SA, Schiff D, Wahl RL

Abstract
Quantitative (18)F-3'-fluoro-3'-deoxy-L-thymidine ((18)F-FLT) positron emission tomography (PET) has potential as a non-invasive tumor biomarker for the objective assessment of response to treatment. To guide interpretation of these quantitative data, we evaluated the repeatability of (18)F-FLT PET as part of a multi-center trial involving patients with high grade glioma.
METHODS: (18)F-FLT PET was performed on 10 patients with recurrent high grade glioma at 5 different institutions within the Adult Brain Tumor Consortium trial ABTC1101. Data were acquired according to a double baseline protocol in which PET was repeated within 2 days of each other with no intervening treatment. On each of the 2 imaging days, dedicated brain PET was performed at 2 time-points, 1 and 3 hours after (18)F-FLT administration. Tumor standardized uptake values (SUVs) and related parameters were measured at a central lab using various volumes-of-interest: isocontour at 30% of the maximum pixel (SUVmean_30%); gradient-based segmentation (SUVmean_gradient); the maximum pixel (SUVmax); and a 1 mL sphere at the region of highest uptake (SUVpeak). Repeatability coefficients (RCs) were calculated from the relative differences between corresponding SUV measurements obtained on the 2 days.
RESULTS: RCs for tumor SUVs were: 22.5 % (SUVmean_30%), 23.8 % (SUVmean_gradient), 23.2 % (SUVmax) and 18.5 % (SUVpeak) at 1 hour post injection. Corresponding data at 3 hours were: 22.4, 25.0, 27.3 and 23.6 %. Normalizing the tumor SUV data with reference to a background region improved repeatability and the most stable parameter was the tumor-to-background (T-to-B) ratio derived using SUVpeak (RC 16.5 %).
CONCLUSION: SUV quantification of (18)F-FLT uptake in glioma has an RC in the range of 18-24 % when imaging began 1 hour after (18)F-FLT administration. The volume-of-interest methodology had a small but not negligible influence on repeatability, with the best performance obtained using SUVpeak. Although changes in (18)F-FLT SUV following treatment cannot be directly interpreted as a change in tumor proliferation, we have established ranges beyond which SUV differences are likely due to legitimate biological effects.

PMID: 27688473 [PubMed - as supplied by publisher]




Evaluation of spleen glucose metabolism in patients with febrile autoimmune diseases using 18F-FDG PET/CT.

Evaluation of spleen glucose metabolism in patients with febrile autoimmune diseases using 18F-FDG PET/CT.

J Nucl Med. 2016 Sep 29;

Authors: Ahn SS, Hwang SH, Jung SM, Lee SW, Park YB, Yun M, Song JJ

Abstract
The purpose of this study was to evaluate the clinical significance of (18)F-fluorodeoxyglucose (FDG) uptake by the spleen in patients with autoimmune disease.
METHODS: We retrospectively reviewed the Severance Hospital's electronic medical records of patients hospitalized for the evaluation of fever who underwent (18)F-FDG positron emission tomography/computed tomography (PET/CT). We found 91 patients with autoimmune diseases and 101 patients with localized infection. (18)F-FDG uptake was assessed by measuring standardized uptake value (SUV) in the spleen and liver. The spleen to liver ratio of the SUVmean (SLRmean) was calculated. Clinical and laboratory parameters were collected and evaluated for association with SLRmean. In-hospital mortality was defined as all-cause mortality during hospital admission for fever.
RESULTS: SLRmean was significantly higher in autoimmune disease compared to localized infectious disease (autoimmune vs.
INFECTION: 1.28 ± 0.43 vs 0.91 ± 0.21, p<0.001). In autoimmune disease, SLRmean was correlated with monocyte count, aspartate aminotransferase, alanine aminotransferase, albumin, and ferritin levels. Receiver operator characteristic curve analysis revealed that the SLRmean had the highest performance compared to laboratory parameters in differentiating autoimmune from localized infectious disease. Multivariate logistic regression analysis demonstrated that high SLRmean and low platelets were significantly associated with in-hospital mortality in febrile autoimmune disease.
CONCLUSION: These findings suggest that spleen glucose metabolism is increased in febrile autoimmune disease. Spleen (18)F-FDG uptake may provide useful information in differentiating febrile autoimmune disease from localized infectious disease and predicting clinical outcomes in febrile autoimmune disease.

PMID: 27688472 [PubMed - as supplied by publisher]




SNMMI Comment on the 2016 Society of Surgical Oncology "Choosing Wisely" Recommendation on the Use of PET/CT in Colorectal Cancer.

SNMMI Comment on the 2016 Society of Surgical Oncology "Choosing Wisely" Recommendation on the Use of PET/CT in Colorectal Cancer.

J Nucl Med. 2016 Sep 29;

Authors: Zukotynski K, Jadvar H, Hope TA, Subramaniam RM, Van Loon K, Varma M, Niederkohr RD

PMID: 27688471 [PubMed - as supplied by publisher]




NAMPT inhibitor GMX1778 enhances the efficacy of 177Lu-DOTATATE treatment of neuroendocrine tumors.

NAMPT inhibitor GMX1778 enhances the efficacy of 177Lu-DOTATATE treatment of neuroendocrine tumors.

J Nucl Med. 2016 Sep 29;

Authors: Elf AK, Bernhardt P, Hofving T, Arvidsson Y, Forssell-Aronsson E, Wängberg B, Nilsson O, Johanson V

Abstract
Neuroendocrine tumors (NETs) can be treated by peptide receptor radionuclide therapy using radiolabeled somatostatin analogs. However, the efficacy of such treatment is low and needs to be optimized.
AIMS: To evaluate the potential radiosensitizing effects of NAMPT inhibition on (177)Lu-DOTATATE treatment in a NET model.
METHODS: Nude mice xenografted with the human NET cell line GOT1 were treated with semi-efficient doses of (177)Lu-DOTATATE (7,5 MBq, i.v.) and/or GMX1778 (100 mg/kg/week, p.o.).
RESULTS: Median time to tumor progression (tumor volume larger than at day 0) was 3 days for controls, 7 days for single dose GMX1778, 28 days for single dose (177)Lu-DOTATATE and 35 days for 3 weekly doses of GMX1778. Combined treatment with (177)Lu-DOTATATE and GMX1778 x1 resulted in a median time to progression of 98 days. After (177)Lu-DOTATATE and 3 weekly doses of GMX1778 none of the tumors progressed within 120 days.
CONCLUSION: The NAMPT inhibitor GMX1778 enhances the efficacy of (177)Lu-DOTATATE treatment and induces a prolonged antitumor response. Combinations of radiolabeled somatostatin analogs and radiosensitizing drugs should be further evaluated to optimize the efficacy of peptide receptor radionuclide therapy in NETs.

PMID: 27688470 [PubMed - as supplied by publisher]




Optical imaging of ionizing radiation from clinical sources.

Optical imaging of ionizing radiation from clinical sources.

J Nucl Med. 2016 Sep 29;

Authors: Shaffer T, Drain CM, Grimm J

Abstract
Nuclear medicine utilizes ionizing radiation for both in vivo diagnosis and therapy. Ionizing radiation comes from a variety of sources, including X-rays, beam therapy, brachytherapy, and various injected radionuclides. While positron emission tomography and single-photon emission computed tomography remain clinical mainstays, optical readouts of ionizing radiation offer numerous benefits and complement these standard techniques. Furthermore, for ionizing radiation sources that cannot be imaged using these standard techniques, optical imaging offers a unique imaging alternative. This article reviews optical imaging of both radionuclide- and beam-based ionizing radiation from high-energy photons and charged particles through mechanisms including radioluminescence, Cerenkov luminescence, and scintillation. Therapeutically, these visible photons have been combined with photodynamic therapeutic agents pre-clinically for increasing therapeutic response at depths difficult to reach with external light sources. Lastly, new microscopy methods that allow single cell optical imaging of radionuclides are reviewed.

PMID: 27688469 [PubMed - as supplied by publisher]