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Biomedical subjects

D M Ackery

Publications and source records attributed to D M Ackery.

13 recordsLinked to original sources
PubMed1992

The treatment of resistant neuroblastoma with 131I-mIBG: alternative methods of dose prescription.

A UK multi-centre study has been carried out to collect medical and dosimetry data from treatments with 131I-metaiodobenzylguanidine (mIBG) for patients suffering from resistant neuroblastoma. All data have been acquired in a standardised way, following strict physics and clinical protocols. The accuracy of three different methods of dose prescription was studied. The results show that the most accurate method involved the use of an initial tracer study to determine the therapeutic activity required to deliver a predetermined absorbed whole-body (WB) dose.

3-Iodobenzylguanidine↗
PubMed1991

The enzyme-inhibitor approach to cell-selective labelling--II. In vivo studies with pIBS in small animals and man.

p-Iodobenzenesulphonamide (pIBS), a potent red cell carbonic anhydrase inhibitor, was used as a carrier for radioiodine in the enzyme-inhibitor approach to cell-specific blood labelling. Radioactivity distribution was monitored in rats and man following i.v. administration of the radiolabelled carrier or of pre-labelled red cells. Rat blood activity fitted a two compartment model; the half-life for overall elimination was 69 +/- 27 h. At 24 h most activity remained associated with red cells, but there was a significant uptake in the large intestine (10 +/- 6%). In man there was no significant accretion by gut or any other organ over 93 h, and the blood clearance was mono-exponential (t1/2 = 9.8 +/- 1.5 days).

Animals↗
PubMed1979

A simple method for correcting left ventricular equilibrium radionuclide angiography for the effects of arrhythmias.

A simple method of correcting equilibrium radionuclide angiographic data for the effects of arrhythmias is proposed. This involves no further acquisition time or inconvenience to the patient. This correction is necessary in patients with marked arrhythmias as the left ventricular time-activity curve (LVTAC) becomes distorted with greater sampling time in the first few frames of the LVTAC than in later frames. This will show on the LVTAC as greater counts in the first few frames and will lead to an overestimation of left ventricular ejection fraction (LVEF) and wall motion. The method proposed normalises each frame to make the contribution from a non-cardiac region constant over the cardiac cycle. Results of the correction are presented and discussed.

Arrhythmias, Cardiac↗
PubMed1979

In vivo measurement of liver perfusion in the normal and partially hepatectomized rat using Tc-99m sulfur colloid.

A nonsacrificial technique for measurement of liver perfusion in rats using Tc-99m sulfur colloid and gamma camera with computer system is described. The results of measurement in normal rats and at various stages after partial hepatectomy are presented and are compared with results obtained by workers using other techniques. The method reported here is simpler to perform than those previously reported and has the additional advantage that frequent sequential determinations of liver perfusion can be made.

Animals↗
PubMed1975

Quantitative liver imaging using 131-I Rose Bengal as an index of liver function and prognosis.

A technique for assessing quantitatively hepatic function by direct measurement of liver parenchymal cell uptake of 131I Rose Bengal using a scintillation camera with a digital store and retrieval system is described. Ninety-four studies were performed on 84 patients with a variety of hepatic disorders over a two-year period, the diagnosis in each case being established by liver biopsy or laparotomy. The results were compared with the clinical, biochemical and histological assessment of the patients. A good correlation was found between the half-time for hepatic uptake of 131I Rose Bengal and the histological changes, as well as with clinical prognosis measured in terms of clinical improvement or deterioration to death. The rate of liver uptake was found to be a better index than the clearance of radioisotope from the blood and was superior to conventional biochemical investigations in both icteric and anicteric patients. The test was not shown to be of clinical value in discriminating between intra- and extrahepatic causes of jaundice. It is suggested that this technique may provide a safe and sensitive method for assessing the severity of liver dysfunction and also for monitoring clinical progress, especially in situations where liver biopsy may be unreliable or hazardous.

Biopsy↗
PubMed1975

Deconvolution analysis of the scintillation camera renogram.

A scintillation camera with digital data store has been used to assess renal function. Analysis of the renogram by deconvolution, using an on-line digital computer, shows promise as a means of expressing renal function in terms of tubular transit times for 123I-Hippuran.

Computers↗
PubMed1975

Xenon-133, 127Xe, and 125Xe for lung function investigations: a dosimetric comparison.

Of the possible radionuclides of xenon, 127Xe and 125 Xe have better physical properties for lung function measurement than 133Xe. A comparison of the radiation doses for these three radionuclides has been made for a typical scintillation camera investigation. Using an exponential model for washin and washout of gas, it is shown that the specific activity-time relationship is always equal to the product of the spirometer concentration and the rebreathing period. It is concluded that of the three radionuclides 127Xe gives the lowest radiation dose during a typical lung function study.

Adipose Tissue↗