In fact, two studies showed no correlation between PLMS and objective measures of excessive daytime sleepiness. In addition, EDS in these patients is best treated with psychostimulants—and not with dopaminergic agents known to suppress PLMS. "Neuromuscular diseases and spinal cord diseases often lead to sleep disturbances due to respiratory dysfunction causing sleep apnea, and they may also cause insomnia related to pain. "Other sleep alterations, such as periodic limb movement disorders in patients with spinal cord disease, have also been uncovered with the widespread use of polysomnography. "Primary hypersomnia in diabetes, hepatic encephalopathy, and acromegaly is rarely reported, but these medical conditions may also be associated with hypersomnia secondary to sleep apnea and periodic limb movement disorder (PLMD).Chronic fatigue syndrome and fibromyalgia can also be associated with hypersomnia. Chronic fatigue syndrome is "characterized by persistent or relapsing fatigue that does not resolve with sleep or rest. Polysomnography shows reduced sleep efficiency and may include alpha intrusion into sleep EEG. It is likely that a number of cases labeled as chronic fatigue syndrome are unrecognized cases of upper airway resistance syndrome" or other sleep disorders, such as narcolepsy, sleep apnea, PLMD, etc.As with chronic fatigue syndrome, fibromyalgia may be associated with anomalous alpha wave activity (typically associated with arousal states) during NREM sleep. Also, researchers have shown that disrupting stage IV sleep consistently in young, healthy subjects causes a significant increase in muscle tenderness—similar to that experienced in "neurasthenic musculoskeletal pain syndrome".
Fluorine-18 has a half-life of 110 min, which requires it to be used promptly once produced; this logistical limitation hampered its adoption in the face of the more convenient technetium-99m-labelled radiopharmaceuticals. However fluorine-18 is generally considered to be a superior radiopharmaceutical for skeletal imaging. In particular it has a high and rapid bone uptake accompanied by very rapid blood clearance, which results in a high bone-to-background ratio in a short time. Additionally the annihilation photons produced by decay of 18F have a high energy of 511 keV  compared to the 140 keV photons of 99mTc. Chemistry
Sodium fluoride has a variety of specialty chemical applications in synthesis and extractive metallurgy. It reacts with electrophilic chlorides including acyl chlorides, sulfur chlorides, and phosphorus chloride. Like other fluorides, sodium fluoride finds use in desilylation in organic synthesis. Sodium fluoride can be used to produce fluorocarbons via the Finkelstein reaction; this process has the advantage of being simple to perform on a small scale but is rarely used on an industrial scale due to the existence of more effective techniques (e.g. Electrofluorination, Fowler process). Other uses
Sodium fluoride is used as a cleaning agent (e.g., as a "laundry sour").Sodium fluoride can be used in a nuclear molten salt reactor. Over a century ago, sodium fluoride was used as a stomach poison for plant-feeding insects. Inorganic fluorides such as fluorosilicates and sodium fluoride complex magnesium ions as magnesium fluorophosphate. They inhibit enzymes such as enolase that require Mg2+ as a prosthetic group. Thus, fluoride poisoning prevents phosphate transfer in oxidative metabolism.