William M. Burch

Passage of Inhaled Particles Into the Blood Circulation in Humans

To the Editor: It is clear from Figure 2 in the article by Nemmar et al1 that their aerosol contained a high level of a species somewhere between Technegas and Pertechnegas. Technegas generation demands a 100% inert atmosphere to work properly. Even minute traces of oxygen will begin to create a mixed oxide species. Machines that are not fully serviced at regular intervals can trap sufficient oxygen in the carbon deposited on the chamber walls, for example, to generate Pertechnegas. The immediate clinical sign is thyroid uptake in the images. This alone is often the first reason to call in a service engineer. There should be no visible thyroid on a study done using a properly functioning machine. Even the original discovery of Pertechnegas arose out of a wrongly filled argon cylinder. A curious alumina micro-aerosol within gas cylinders made of aluminum was implicated in a whole series of inadvertent Pertechnegas studies generated from …

The observation of fullerenes in a Technegas lung ventilation unit.

Evidence is provided to show that Technegas has a structure compatible with the Buckminsterfullerene model C60 in which 99Tcm atoms are trapped.

Use of Technegas as a radiopharmaceutical for the measurement of gastric emptying.

Abstract. Many radiopharmaceuticals and test meals that are used to measure gastric emptying are less than optimal. A vegetable-based solid meal, such as rice, labelled with a radiopharmaceutical that also has the capacity to measure gastric emptying of liquids, is likely to be ideal. The role of Technegas as a radioisotopic marker to measure gastric emptying of rice and liquids was evaluated. Technegas-labelled rice was incubated in 0.9% saline, 1 M HCl and simulated gastric fluid (3.2 g/l pepsinogen, pH 2–3) to assess stability of the label. In eight healthy volunteers gastric emptying of two meals – 200 g rice (370 kcal) and 75 g dextrose dissolved in 300 ml water (300 kcal), both labelled with 20 MBq of Technegas – was measured scintigraphically. Over 4 h, the average label stability was 93.7%±0.5% in 0.9% saline, 91.0%±0.4% in 1 M HCl and 93.6%±0.7% in simulated gastric juice. The lag phase was longer for rice than dextrose (25±7 min vs 4±2 min; P<0.05), but there was no difference in the post-lag emptying rate (2.1±0.3 kcal/min vs 1.7±0.2 kcal/min; P=0.2) between the two meals. We conclude that Technegas is a suitable radiopharmaceutical for measurement of gastric emptying of rice and nutrient-containing liquids.

Focus on…: Čerenkov radiation

Dear Sir, The “Focus on...” article in the March 2011 issue of EJNMMI [1] omitted one excellent Cerenkov emitter, P, and a classical organ in which to exploit it, namely, the eye. In 1971, I demonstrated Cerenkov radiation from P in a rabbit’s eye following IV injection of the orthophosphate [2]. It was the proof of concept stage of a project to differentially diagnose ocular melanoma. The basic apparatus was to have a binocular system where the unaffected eye tracked a moving spot on a display while the eye under examination was monitored with a light detector, thereby mapping the Cerenkov distribution on the back of that eye. If ocular melanoma still poses a diagnostic dilemma, this simple technique is waiting to be tested.