Radiotherapy and radiation oncology play a key role in the clinical management of patients suffering from oncological diseases. In clinical routine, anatomic imaging such as contrast-enhanced CT and ...MRI are widely available and are usually used to improve the target volume delineation for subsequent radiotherapy. Moreover, these modalities are also used for treatment monitoring after radiotherapy. However, some diagnostic questions cannot be sufficiently addressed by the mere use standard morphological imaging. Therefore, positron emission tomography (PET) imaging gains increasing clinical significance in the management of oncological patients undergoing radiotherapy, as PET allows the visualization and quantification of tumoral features on a molecular level beyond the mere morphological extent shown by conventional imaging, such as tumor metabolism or receptor expression. The tumor metabolism or receptor expression information derived from PET can be used as tool for visualization of tumor extent, for assessing response during and after therapy, for prediction of patterns of failure and for definition of the volume in need of dose-escalation. This review focuses on recent and current advances of PET imaging within the field of clinical radiotherapy / radiation oncology in several oncological entities (neuro-oncology, head & neck cancer, lung cancer, gastrointestinal tumors and prostate cancer) with particular emphasis on radiotherapy planning, response assessment after radiotherapy and prognostication.
Although there has been a growing literature on cooperative diversity, the current literature is mainly limited to the Rayleigh fading channel model, which typically assumes a wireless communication ...scenario with a stationary base station antenna above rooftop level and a mobile station at street level. In this paper, we investigate cooperative diversity for intervehicular communication based on cascaded Nakagami fading. This channel model provides a realistic description of an intervehicular channel where two or more independent Nakagami fading processes are assumed to be generated by independent groups of scatterers around the two mobile terminals. We investigate the performance of amplify-and-forward relaying for an intervehicular cooperative scheme assisted by either a roadside access point or another vehicle that acts as a relay. Our diversity analysis reveals that the cooperative scheme is able to extract the full distributed spatial diversity. We further formulate a power-allocation problem for the considered scheme to optimize the power allocated to the broadcasting and relaying phases. Performance gains up to 3 dB are obtained through optimum power allocation, depending on the relay location.
Intracranial arachnoid cysts are cystic congenital malformations, filled with cerebrospinal fluid (CSF) originating from the arachnoid membrane. Generally, giant arachnoid cysts present with symptoms ...related to increased intracranial pressure, hydrocephalus or cognitive disorders, endocrinological problems, growth retardation, seizures, headache, and nonspecific symptoms such as dizziness. They can be detected by imaging when they become symptomatic or incidentally in childhood and adulthood. Our case was referred to our clinic because of ptosis and facial asymmetry found on examination. Subsequently, a intracranial giant arachnoid cyst was found incidentally on cranial computed tomography (CT).
In an 18-month-old male infant admitted with ptosis, left frontal bulging and a dystopic globe with ptosis of the left upper lid were noted. The left half of the facial region and the left nostril also appeared to be asymmetrically elongated downward relative to the right. Fundus examination revealed an optic disc coloboma in the left eye. On general physical examination, he was unable to walk. A giant fronto-temporo-parietal arachnoid cyst with the cerebral parenchyma shifted 2cm to the right of the midline was observed on cranial CT. After a cysto-peritoneal shunt was performed, the physical appearance of our patient returned to normal.
Ptosis cases accompanied by abnormalities such as optic disc coloboma and facial asymmetry should be evaluated for possible midline defects and intracranial pathologies prior to eyelid surgery.
18F-fluoroestradiol (FES) positron emission tomography (PET)/computed tomography (CT) is considered an accurate diagnostic tool to determine whole-body endocrine responsiveness. In the endocrine ...therapy (ET)-FES trial, we evaluated 18F-FES PET/CT as a predictive tool in estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2−) metastatic breast cancer (MBC).
Eligible patients underwent an 18F-FES PET/CT at baseline. Patients with standardized uptake value (SUV) ≥ 2 received single-agent ET until progressive disease; patients with SUV < 2 were randomized to single-agent ET (arm A) or chemotherapy (ChT) (arm B). The primary objective was to compare the activity of first-line ET versus ChT in patients with 18F-FES SUV < 2.
Overall, 147 patients were enrolled; 117 presented with 18F-FES SUV ≥ 2 and received ET; 30 patients with SUV < 2 were randomized to ET or ChT. After a median follow-up of 62.4 months, 104 patients (73.2%) had disease progression and 53 died (37.3%). Median progression-free survival (PFS) was 12.4 months 95% confidence interval (CI) 3.1-59.6 months in patients with SUV < 2 randomized to arm A versus 23.0 months (95% CI 7.7-30.0 months) in arm B, hazard (HR) = 0.71, 95% CI 0.3-1.7 months; median PFS was 18.0 months (95% CI 11.2-23.1 months) in patients with SUV ≥ 2 treated with ET. Median overall survival (OS) was 28.2 months (95% CI 14.2 months-not estimable) in patients with SUV < 2 randomized to ET (arm A) versus 52.8 months (95% CI 16.2 months-not estimable) in arm B (ChT). Median OS was not reached in patients with SUV ≥ 2. 60-month OS rate was 41.6% (95% CI 10.4% to 71.1%) in arm A, 42.0% (95% CI 14.0% to 68.2%) in arm B, and 59.6% (95% CI 48.6% to 69.0%) in patients with SUV ≥ 2. In patients with SUV ≥ 2, 60-month OS rate was 72.6% if treated with aromatase inhibitors (AIs) versus 40.6% in case of fulvestrant or tamoxifen (P < 0.005).
The ET-FES trial demonstrated that ER+/HER2− MBC patients are a heterogeneous population, with different levels of endocrine responsiveness based on 18F-FES CT/PET SUV.
•18F-FES PET/CT may be used as a predictive tool of efficacy of ET to assess overall endocrine sensitivity.•Endocrine-sensitive patients (SUVmax ≥ 2) treated with single-agent ET have a prolonged OS.•In endocrine-sensitive patients, PFS and OS related to the use of AI were significantly higher than ER-directed agents.•18F-FES PET/CT can be used as a valid alternative to biopsy.
In this study, a thermophilic bacterium isolated from a thermal source in Turkey and identified as
Geobacillus pallidus
P26 was used to produce the alkaline phosphatase (ALP) enzyme. The enzyme was ...partially isolated by salting out the supernatant with saturated ammonium sulphate. Then, the enzyme was purified 23 times using ion-exchange (DEAE-Sepharose) and size-exclusion chromatography (Sephacryl S-200). Using
p
-nitrophenyl phosphate (pNPP) substrate, the maximum reaction velocity (
V
max
) of the purified enzyme was calculated as 0.255 µmol/min/mg and Michaelis-Menten constant (
K
m
) for pNPP (p-nitrophenyl phosphate) as 3.92 mM.
k
cat
(turnover number) and
k
cat
/
K
m
were calculated as 0.812 s
–1
and 207.14 s
–1
M
–1
, respectively. The half-life of the enzyme (
t
1/2
) purified from
Geobacillus pallidus
G26 was calculated as 38 hours at 60°C, 14 hours at 70°C and 1.5 hours at 80°C. The thermodynamic parameters of ALP (
and
) were also calculated. The enzymes extracted from thermophilic bacteria can maintain their stability at high temperatures for a longer period. This characteristic is favorable for implementations that require high temperatures.
Introduction
Tyrosine kinase (TKI) and checkpoint inhibitors (CI) prolonged overall survival in metastatic renal cell carcinoma (mRCC). Early prediction of treatment response is highly desirable for ...the individualization of patient management and improvement of therapeutic outcome; however, serum biochemistry is unable to predict therapeutic efficacy. Therefore, we compared
18
F-PSMA-1007 PET imaging for response assessment in mRCC patients undergoing TKI or CI therapy compared to CT-based response assessment as the current imaging reference standard.
Methods
18
F-PSMA-1007 PET/CT was performed in mRCC patients prior to initiation of systemic treatment and 8 weeks after therapy initiation. Treatment response was evaluated separately on
18
F-PSMA-PET and CT. Changes on PSMA-PET (SUV
mean
) were assessed on a per patient basis using a modified PERCIST scoring system. Complete response (CR
PET
) was defined as absence of any uptake in all target lesions on posttreatment PET. Partial response (PR
PET
) was defined as decrease in summed SUV
mean
of > 30%. The appearance of new, PET-positive lesions or an increase in summed SUV
mean
of > 30% was defined as progressive disease (PD
PET
). A change in summed SUV
mean
of ± 30% defined stable disease (SD
PET
). RECIST 1.1 criteria were used for response assessment on CT. Results of radiographic response assessment on PSMA-PET and CT were compared.
Results
Overall, 11 mRCC patients undergoing systemic treatment were included. At baseline PSMA-PET
1
, all mRCC patients showed at least one PSMA-avid lesion. On follow-up PET
2
, 3 patients showed CR
PET
, 3 PR
PET
, 4 SD
PET
, and 1 PD
PET
. According to RECIST 1.1, 1 patient showed PR
CT
, 9 SD
CT
, and 1 PD
CT
. Overall, concordant classifications were found in only 2 cases (2 SD
CT + PET
). Patients with CR
PET
on PET were classified as 3 SD
CT
on CT using RECIST 1.1. By contrast, the patient classified as PR
CT
on CT showed PSMA uptake without major changes during therapy (SD
PET
). However, among 9 patients with SD
CT
on CT, 3 were classified as CR
PET
, 3 as PR
PET
, 1 as PD
PET
, and only 2 as SD
PET
on PSMA-PET.
Conclusion
On PSMA-PET, heterogeneous courses were observed during systemic treatment in mRCC patients with highly diverging results compared to RECIST 1.1. In the light of missing biomarkers for early response assessment, PSMA-PET might allow more precise response assessment to systemic treatment, especially in patients classified as SD on CT.
Background NETTER-1 trial demonstrated high efficacy and low toxicity of four cycles of Peptide Receptor Radionuclide Therapy (PRRT) in patients with metastasized NET. The present study evaluates the ...outcome of further PRRT cycles in the so called salvage setting in patients after initial response to four therapy cycles and later progression. Methods Thirty five patients (pat.) (25 male, 10 female, 63 + or - 9 years) with progressive, metastasized NET (23 small intestinal, 5 lung, 4 CUP, 1 rectal, 1 gastric and 1 paraganglioma) were included. All patients previously received 4 PRRT cycles with .sup.177Lu-DOTATATE and showed initial response. SPECT based dosimetry was applied to determine kidney and tumor doses. Therapy response was evaluated using .sup.68Ga-DOTATATE PET/CT (with high dose CT), CT alone or MRI (RECIST 1.1), toxicity was defined using CTCAE 5.0 criteria. .sup.99mTc99-MAG3 scintigraphy was used to assess potential renal tubular damage. Progression free survival (PFS) and Overall survival (OS) analysis was performed with the Kaplan-Meier-method. Results The median PFS after initial PRRT was 33 months (95% CI: 30-36). The mean cumulative dose for including salvage PRRT was 44 GBq (range 33.5-47). One pat. (2.9%) showed grade 3 hematotoxicity. Kidney dosimetry revealed a mean cumulative kidney dose after a median of 6 PRRT cycles of 23.8 Gy. No grade 3 / 4 nephrotoxicity or relevant decrease in renal function was observed. Follow-up imaging was available in 32 patients after salvage therapy. Best response according to RECIST 1.1. was PR in one patient (3.1%), SD in 26 patients (81.3%) and PD in 5 patients (15.6%). PFS after salvage therapy was 6 months (95% CI: 0-16; 8 patients censored). Mean OS after initial PRRT was 105 months (95% CI: 92-119) and 51 months (95% CI: 41-61) after start of salvage therapy. Median OS was not reached within a follow-up of 71 months after initial PRRT and 25 months after start of salvage PRRT, respectively. Conclusions Salvage therapy with .sup.177Lu-DOTATATE is safe and effective even in patients with extensive previous multimodal therapies during disease progression and represents a feasible and valuable therapy option for progressive NET. Keywords: PRRT, Salvage therapy, NET, SPECT, Dosimetry, Survival
AIM: To evaluate the factors associated with delayed diagnosis of foreign body aspiration (FBA) in children and to compare clinical, radiological and bronchoscopic findings in the patients with ...suspected FBA.
MATERIAL AND METHODS: The medical records of 214 children who underwent bronchoscopy for suspected FBA were reviewed. The data were analysed in three groups: the patients with negative bronchoscopy for FBA (group I), early (group II) and delayed diagnosis (group III).
RESULTS: The majority of the patients with FBA were between 1 and 3 years of age. Choking episodes, coughing and decreased breath sounds were determined in a significantly higher number of the patients with FBA. The plain chest radiography revealed radio-opaque foreign bodies (FBs) in 19.7% of all patients with FBA. Emphysema was more common in children with FBA. Clinical and radiological findings of pneumonia and atelectasis were significantly more common in the groups with negative bronchoscopy and with delayed diagnosis (
p<0.01). The FBs were most frequently of vegetable origin, such as seeds and peanuts. A significant tissue reaction with inflammation was more common in the delayed cases.
CONCLUSION: To prevent delayed diagnosis, characteristic symptoms, signs and radiological findings of FBA should be checked in all suspected cases. As clinical and radiological findings of FBA in delayed cases may mimic other disorders, the clinician must be aware of the likelihood of FBA. Regardless of radiological findings, bronchoscopy should be considered in patients with an appropriate history.
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