Enamel microabrasion: An overview of clinical and scientific considerations

Superficial stains and irregularities of the enamelare generally what prompt patients to seek dental intervention to improve their smile. These stains or defects may be due to hypoplasia, amelogenesis imperfecta, mineralized white spots, or fluorosis, for which enamel microabrasion is primarily indicated. Enamel microabrasion involves the use of acidic and abrasive agents, such as with 37% phosphoric acid and pumice or 6% hydrochloric acid and silica, applied to the altered enamel surface with mechanical pressure from a rubber cup coupled to a rotatory mandrel of a lowrotation micromotor. If necessary, this treatment can be safely combined with bleaching for better esthetic results. Recent studies show that microabrasion is a conservative treatment when the enamel wear is minimal and clinically imperceptible. The most important factor contributing to the success of enamel microabrasion is the depth of the defect, as deeper, opaque stains, such as those resulting from hypoplasia, cannot be resolved with microabrasion, and require a restorative approach. Surface enamel alterations that result from microabrasion, such as roughness and microhardness, are easily restored by saliva. Clinical studies support the efficacy and longevity of this safe and minimally invasive treatment. The present article presents the clinical and scientific aspects concerning the microabrasion technique, and discusses the indications for and effects of the treatment, including recent works describing microscopic and clinical evaluations.     

Double Aortic Arch: An Unreported Anomaly with Kabuki Syndrome

Kabuki syndrome is a rare congenital disorder characterized by mental retardation, postnatal dwarfism, visceral anomalies, and peculiar facies (resembling the makeup of actors in Kabuki, traditional Japanese theater) initially described in Japan. Congenital heart and great vessel defects are the most frequent visceral anomalies found in children with Kabuki syndrome. Although many cardiovascular defects have been described, a double aortic arch has never been reported with Kabuki syndrome.     

Bone marrow dosimetry in peptide receptor radionuclide therapy with [177Lu-DOTA0,Tyr3]octreotate

Purpose  Adequate dosimetry is mandatory for effective and safe peptide receptor radionuclide therapy (PRRT). Besides the kidneys, the bone marrow is a potentially dose-limiting organ. The radiation dose to the bone marrow is usually calculated according to the MIRD scheme, where the accumulated activity in the bone marrow is calculated from the accumulated radioactivity of the radiopharmaceutical in the blood. This may underestimate the absorbed dose since stem cells express somatostatin receptors. We verified the blood-based method by comparing the activity in the blood with the radioactivity in bone marrow aspirates. Also, we evaluated the absorbed cross-dose from the source organs (liver, spleen, kidneys and blood), tumours and the so-called “remainder of the body” to the bone marrow. Methods  Bone marrow aspirates were drawn in 15 patients after treatment with [¹⁷⁷Lu-DOTA⁰,Tyr³]octreotate. Radioactivity in the bone marrow was compared with radioactivity in the blood drawn simultaneously. The nucleated cell fraction was isolated from the bone marrow aspirate and radioactivity was measured. The absorbed dose to the bone marrow was calculated. The results were correlated to the change in platelet counts 6 weeks after treatment. Results  A strong linear correlation and high agreement between the measured radioactivities in the bone marrow aspirates and in the blood was found (r=0.914, p<0.001). No correlation between the calculated absorbed dose in the bone marrow and the change in platelets was found. There was a considerable contribution from other organs and the remainder of the body to the bone marrow absorbed dose. Conclusion  (1) After PRRT with [¹⁷⁷Lu-DOTA⁰,Tyr³]octreotate, the radioactivity concentration in the bone marrow is identical to that in the blood; (2) There is no significant binding of the radiopharmaceutical to bone marrow precursor stem cells; (3) The contribution of the cross dose from source organs and tumours to the bone marrow dose is significant; and (4) There is considerable variation in bone marrow absorbed dose between patients. These findings imply that for individual dose optimization, individual calculation of the bone marrow absorbed dose is necessary.     

EANM procedure guideline for brain perfusion SPECT using 99mTc-labelled radiopharmaceuticals, version 2

These guidelines summarize the current views of the European Association of Nuclear Medicine Neuroimaging Committee (ENC). The purpose of the guidelines is to assist nuclear medicine practitioners when making recommendations, performing, interpreting, and reporting the results of brain perfusion single photon emission computed tomography (SPECT) studies using ^99mTc-labelled radiopharmaceuticals. The aim is to achieve a high quality standard for brain perfusion SPECT imaging, which will increase the diagnostic impact of this technique in clinical practice. The present document replaces a former version of the guideline published in 2001 which was inspired by the Society of Nuclear Medicine Procedure Guideline for Brain Perfusion SPECT [1], the views of the Society of Nuclear Medicine Brain Imaging Council [2], and the individual experience of experts in European countries. The guidelines are intended to present information specifically adapted to European practice. The information provided should be taken in the context of local conditions and regulations.