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Posts Tagged ‘Positron Emission Tomography’

PET scan is feasible for medical prognosis in patients with inoperable lung cancer that have most aggressive tumors: a study report

 

(Courtesy: Mitch Machtay, MD, of the Seidman Cancer Center at University Hospitals)

Physicians can now easily determine patients that require specific cancer treatment, to manage their medical condition. Lung cancer is one of the prime cause of deaths in the United States.

Unlike other imaging methods (computed tomography etc.) for detailed body structure, a PET scan brings out physiologic processes in organs; chemical activity and metabolic changes in cancer cells can be observed through PET scan; regions of greater intensity through scan let care providers find/locate the disease easily.

Through the technology, care providers can customize treatment for patients with advanced lung cancers, in a better way; the study encompassed patients with stage III lung cancer that had PET scans, before, and after combined treatment course of radiotherapy and chemotherapy.

In comparison to normal cells, cancerous cells absorb sugar molecules at a higher rate, and show up clearly on PET scans; researchers evaluated FDG (radioactive sugar molecule) uptake in cancer, i.e. how swiftly the tumors absorb radioactive sugar molecules.

Researchers found that patients with higher level of FDG uptake in post treatment scan had more aggressive tumors with likelihood of recurrence. The recurrence rate of cancer was estimated to be more in patients with higher FDG uptake rates than the standard uptake value; such patients usually have lower survival rate than others.

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11C-4DST PET is feasible for brain tumor imaging; pharmacological safety and dosimetry are reasonable at the dose necessary for suitable PET images.

 

The medical research study was contributed by Jun Toyohara (Positron Medical Center, Tokyo Metropolitan Institute of Gerontology) and associates. (Courtesy: The Journal of Nuclear Medicine)

Lately, the team developed [methyl-11C]4′-thiothymidine (11C-4DST) as an in vivo cell propagation marker; the research study was to decide radiation dosimetry, security, allocation/distribution and primary brain tumor imaging of 11C-4DST in humans.

Radiation dosimetry and multi-organ biodistribution of 11C-4DST were evaluated in 3 subjects that passed through 2-h whole-body PET imaging.

OLINDA program was utilized for radiation dosimetry; about 6 patients (brain tumor) passed through dynamic 11C-4DST scans with arterial blood sampling; the patients were even assessed with 11C-methionine PET; plasma substance and urine samples were construed through liquid chromatography.

Gadolinium-enhanced T1-weighted MRI was utilized for perturbation of blood-brain obstruction in tumor tissue.

No adverse events were reported during study phase with any of subjects; 11C-4DST PET showed selective consumption in the bone marrow; high-level uptake was observed in liver.

Urinary bladder wall has had highest absorbed dose; the appraised effective dose for 11C-4DST was 4.2 μSv/MBq.

11C-4DST demonstrated slight uptake in normal tissues (brain), ensuing in low background activity for tumor imaging.

In comparison, 11C-4DST PET showed swift uptake in truculent tumor masses; no sign of 11C-4DST was found in clinically fixed disorder in which 11C-methionine uptake was high.

The allocation pattern of 11C-methionine in tumor sections was not always similar to that of 11C-4DST; examination of plasma samples through liquid chromatography showed that more than 60% of radioactivity was present as unaltered 11C-4DST at 20 min.

Conclusion: small group patient study – primary findings show that 11C-4DST PET is plausible for brain tumor imaging; pharmacological safety and dosimetry were reasonable at the dose necessary for suitable PET images.

PET scan demonstrated well, in comparison to TTE/TEE and multislice CT for infectious endocarditis.

• Infectious Endocarditis can be analyzed, once the accretion of FDG is observed on a PET scan in suspected region.
• PET scan discovered out FDG accumulation in region of prosthetic blood vessel of the right ventricular outflow tract.

The medical research was conducted by Tsuneaki Kenzaka, MD, Miho Shimoshikiryo, MD, Akihito Kitao, MD, Kazuomi Kario, MD, and Masayoshi Hashimoto, MD. The clinical trial is available in the Journal of Nuclear Cardiology.

The analysis of infectious endocarditis is characteristically based on clinical presentation, blood cultures and echocardiogram findings. Echocardiography is fundamental in the analysis/management of patients with infectious endocarditis.

Medical researches elaborated a medical case of infectious endocarditis, which could not be analyzed through Transthoracic Echocardiography (TTE) and Transesophageal Echocardiogram (TEE). The 35-year-old patient who had been suffering from high fever for more than 2 weeks had a significant medical history of tetralogy of fallot. On examination, no abnormal findings were observed in the blood and urine tests, except for increased white blood cells.

CAT scans with contrast medium and otherwise of the chest, abdomen and head did not divulge cause for the febricity. His medical history and current illness pointed out to infectious endocarditis. Due to artifact, the pulmonary valves could not be envisioned by. Streptococcus Viridans was recognized out in blood cultures, and valve repair was adjudicated for infectious endocarditis.

64-slice CTA was carried out to identify out infectious focal areas, researchers found low-density region in the valves, but could not differentiate it out from fuzzy artifact image in the simulated blood vessel site of the right ventricular outflow tract (RVOT).

PET scan then was adjudicated as a substitute for the procedure. The scan was acquired after instilling the patient with 18F-FDG (4 MBq/kg). Positron emission tomography apparently divulged out the localized accretion of FDG in the contrived blood vessel site of the RVOT. The second scan was carried out after treatment phase of six weeks. It did not show any accretion of FDG in the fraction of the artificial blood vessel.

Except for heparin administration, the second PET scan was administered as per the standard protocol. The patient recuperated with the treatment schedule, as the accumulation vanished after the treatment.

Conclusion: PET scan is effective in treating grave medical cases of infective endocarditis.

In a recent scientific research development study, conducted by medical research scientists from the US Department of Energy’s Brookhaven National Laboratory, Stony Brook University and other confederates established and confirmed out the possibilities of wearable/vesture portable PET scanner (Positron Emission Tomography) that the group has formulated for rats, as this technology tool will facilitate neuroscientists for incorporated, and simulation study of brain function (to gauge on molecular processes in the brain) and behavioral patterns in wide awake and alert animals, in motion, as PET studies in animals have helped the scientific research team to expose/discover out the molecular corroboration of conditions pertain to drug addiction.

The team had to freeze animals through general anesthesia to study them with PET, but immobilization and to make them unconscious through anesthetic treatment does not make it feasible for to concurrently study neurochemistry and the actions and behaviors of the animals, as to gauge the actions ensuing in the brain. The advancement of research team was to trim down the requirement for of control/moderation through development of PET scanner, which would be in motion with the animals, thereby amplifying the possibilities of to directly correlate the behavioral and imaging data obtained, simultaneously.

The miniature donut shaped design (portable vesture – PET scanner) that has been evolved out after so many years of scientific development phase is very easy to be worn just like a collar on a rat’s head for concurrent research and study of its behavior and brain functions. This light-weight miniature PET scanner (vesture/portable) nicknamed as RatCAP by the team, where the technology-gadget is counteracted with springs and stabilizers to facilitate the animals – considerable liberty of movement, where the PET scanner (portable) gauges on the stress hormones of the rats, when they are in motion, and up with daily cycle, and research team found that the rats were quite comfortable with the worn-up gadget (PET scanner), as they were able to move freely with it.

To authenticate the study of this portable scanner (PET) of concurrent studies for to gauge behavior and brain functions of the rat, the research team carried out tests with PET radiotracer (11C-raclopride), as it incorporates radioactive, positron releasing isotope of carbon. When the positrons act together/interrelate with electrons in a normal matter, they instantly destroy out each other, and emit back gamma rays. Detector in the donut shaped PET scanner is capable enough for to apprehend the signals from the gamma rays for to recognize out the location and absorption of the radioactive tracer in the body of the rat.

The radioactive tracer connects/combines up with receptors for dopamine, which is a brain chemical concerned with the movement and other brain memory formation.  The higher signal received out from the tracer shows out to presence of less natural dopamine in any specific part of the brain, whereas a low signal shows out to precise regions of the brain that has discharged dopamine. Through the research study, the team wanted to ensure if the portable scanner (vesture) could be utilized for to associate behavior of the brain with dopamine levels, to ensure normal functioning of the nervous system, but on an astonishing note the activity level was reciprocally associated to dopamine levels, as more active animals showed up lower amount of dopamine, as suggested on stronger radioactive tracer signals.

Scientists term it to be an unreasonable result, as the behavior establishment is generally linked with an increase in dopamine level, and on the same ground the team said their data can be taken as an exception to conventional prototypes, and eventually augments the understanding of the dopamine system. But, irrespective of the direction, the outcomes evidently show out that RatCAP can associate/compare behavioral measures with brain function measurements in a significant and useful way. The research team even put forward their results on rats wearing RatCAP, in motion about their cages along with animals that were given anesthesia, as they even compared out both the methods for to administer radioactive tracer, to instill all at once, and in a firm/steady infusion for to maintain concentration in the blood.

Researchers believe these measurements will aid them for to further improve the technique, and to add value to the results obtained through RatCAP in contrast to other study techniques. Now the research team is up for to utilize RatCAP for to explore distinctive behavioral expressions, which could be associated with concurrently gathered PET data.

The wait is over for Pakistan’s patients…no more visas, or long train travels to India to get  a PET scan done.

PET (Positron Emission Tomography) scan is considered to be a valuable tool for diagnosis, staging, treatment planning as well as follow-up of patients with cancer (not to forget the other diseases in which PET/CT scaning is valuable).  Till now, the patients from Pakistan had to go to India, Europe or Singapore for a PET scan.

Pakistan has taken a leap forward in developing its healthcare system with the installation of the nation’s first PET/CT scanner in the Shaukat Khanum Memorial Cancer Hospital & Research Centre (SKMCH&RC), with donations from local as well as foreign nationals.