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Biomedical subjects

C P Wells

Publications and source records attributed to C P Wells.

At least 19 recordsLinked to original sources
PubMed1999

South Thames quality standard for nuclear medicine equipment. South Thames Region Nuclear Medicine Specialty Service Committee.

A survey of the quality assurance of the nuclear medicine equipment in use in the South Thames Region was undertaken as part of the clinical audit process within the region. The results revealed the variation in practice across the region and highlighted the need for an agreed quality standard, together with the appropriate level of physics support to provide that standard.

Data Collection↗
PubMed1997

South Thames Nuclear Medicine Survey 1996-97. South Thames Regional Nuclear Medicine Specialty Service Committee.

Data on the equipment available, staffing levels, number and type of procedures carried out in the South Thames Region during 1993-94 and 1996-97 are presented. These are compared with national data for 1993. The number of gamma cameras has increased by 5%, overall staffing by 15% and the number of procedures has increased by 31%. There has been a disproportionate increase in the technically more complex procedures, for example cardiac tomography (84%). Regional data have been collated since 1979 and techniques have been established to ensure consistency. Staffing levels, although improving, do not meet the minimum levels recommended by professional bodies. This raises questions about the quality and, possibly, the legality of the service provision.

England↗
PubMed1996

Radiation dose rates from patients receiving iodine-131 therapy for carcinoma of the thyroid.

Patients treated with radioiodine present a radiation hazard and precautions are necessary to limit the radiation dose to family members, nursing staff and members of the public. The precautions advised are usually based on instantaneous dose rates or iodine retention and do not take into account the time spent in close proximity with a patient. We have combined whole-body dose rate measurements taken from 86 thyroid cancer patients after radioiodine administration with published data on nursing and social contact times to calculate the cumulative dose that may be received by an individual in contact with a patient. These dose estimates have been used to calculate restrictions to patients behaviour to limit received doses to less than 1 mSv. We have also measured urinary iodide excretion in 19 patients to estimate the potential risk from the discharge of radioiodide into the domestic drainage system. The dose rate decay was biexponential for patients receiving radioiodine to ablate the thyroid after surgery (the ablation group, A) and monoexponential for these receiving subsequent treatments for residual or recurrent disease (the follow-up group, FU). The faster clearance in the follow-up patients generally resulted in less stringent restrictions than those advised for ablation patients. For typical activities of 1850 MBq for the ablation patients and 3700 MBq or 7400 MBq for the follow-up patients, the following restrictions were advised. Patients could travel in a private car for up to 8h on the day of treatment (for an administered activity of 1850 MBq in group A) or 4 and 2h (for activities of 3700 or 7400 MBq in group FU) respectively. Patients should remain off work for 3 days (1850 MBq/group A) or 2 days (up to 7400 MBq/group FU). Partners should avoid close contact and sleep apart for 16 days (1850 MBq/group A) or 4-5 days (3700 or 7400 MBq/group FU). Contact with children should be restricted according to their age, ranging from 16 days (1850 MBq/group A) or 4-5 days (3700 or 7400 MBq in group FU) for younger children, down to 10 days (1850 MBq/group A) or 4 days (up to 7400 MBq/group FU) for older children. The cumulative dose to nursing staff for the week after treatment was dependent on patient mobility and was estimated at 0.08 mSv for a self-caring patient to 6.3 mSv for a totally helpless patient (1840 MBq/group A). Corresponding doses to nurses looking after patients in group FU were 0.18-12.3 mSv (3700 MBq) or 0.36-24.6 mSv (7400 MBq). Sensible guidelines can be derived to limit the dose received by members of the public and staff who may come into contact with cancer patient treated with radioiodine to less than 1 mSv. The rapid clearance of radioiodine in patients treated on one or more than one occasion means that therapy could be administered at home to selected patients with suitable domestic circumstances. In most cases the restriction times, despite the high administered activities, are less than those for patients treated for thyrotoxicosis. The concentration of radioiodide in domestic drainage systems should not pose a significant risk.

Adult↗
PubMed1995

Home reporting for the nuclear clinician?

The computer-based 'home office' is becoming a widely accepted mode of operation for modern businesses. It is implausible to believe that a nuclear medicine department can be covered permanently at a distance by a single physician, but it should be possible to provide cover for colleagues during sickness or at night or weekends. We have used a 486 PC with a high-resolution screen and software provided by LINK Medical Ltd to obtain images from hospital sites using a modem link to ADAC, Bartec and Nuclear Diagnostic SUN workstations. The data were transferred via standard telephone lines to the homes of two of the authors. During a trial period lasting several months, 60 lung scans, 20 bone scans, 1 gastrointestinal bleeding study, 4 leukocyte scans, 5 bone tomograms, 9 renograms, 6 myocardial perfusion tomograms and 2 gated cardiac studies were transferred. The system allowed transfer of a 128 x 128 eight-view lung scan to be completed in approximately 2 min. The program on the PC allowed alteration of individual image contrast, image rotation, cine display and a variety of colour scales to enhance image interpretation. A system to transfer chest X-rays has been developed and typical transfer times are approximately 3.5 min. Within the viewing protocol on the PC, a reporting window was available with the ability to fax the report directly to the hospital. The system allowed consultants who live at a distance from their nuclear medicine departments to provide cover and is now used as an integral part of our out-of-hours service. The system also allows cover of satellite units or to provide cover for junior staff at night or weekends.

Computer Communication Networks↗
PubMed1995

Gamma camera purchasing.

The purchase of a new gamma camera is a major undertaking and represents a long-term commitment for most nuclear medicine departments. The purpose of tendering for gamma cameras is to assess the best match between the requirements of the clinical department and the equipment available and not necessarily to buy the 'best camera' [1-3]. After many years of drawing up tender specifications, this paper tries to outline some of the traps and pitfalls of this potentially perilous, although largely rewarding, exercise.

Gamma Cameras↗
PubMed1989

99Tcm sestamibi--a new agent for parathyroid imaging.

Parathyroid imaging using 99Tcm sestamibi has been carried out prior to surgery in five patients with hyperparathyroidism and the results compared with a standard preoperative localization technique using 201Tl (thallous chloride). The 99Tcm sestamibi correctly localized all abnormal glands and showed higher parathyroid to thyroid uptake in three of four parathyroid adenomas. Both agents showed localization in a thyroid adenoma. The higher uptake of sestambi and better imaging properties of its 99Tcm radiolabel means that the agent may replace thallium for routine preoperative parathyroid localization.

Drug Evaluation↗
PubMed1986

Liver scintiscanning as a screening test in the detection of alcoholic cirrhosis.

Ninety-nine patients with alcohol related problems underwent a liver scintiscan and biopsy. The scan changes were graded and compared with the histological changes found from percutaneous liver biopsy. The overall correlation between scan and biopsy changes was poor. However, scintiscanning was found to be highly sensitive (90%) in detecting cirrhosis and for this reason is useful as a screening test in selecting alcoholic patients for biopsy.

Biopsy↗
PubMed1986

99Tcm-MDP, 67Ga-citrate and 111In-leucocytes for detecting prosthetic hip infection.

An assessment was made of the roles of 99Tcm-MDP, 67Ga-citrate and 111In-leucocytes in identifying infected hip prostheses. Fifty painful prosthetic hips were investigated with a 99Tcm-MDP bone scan and an 111In-labelled leucocyte scan (ILLS). In 32 cases, a 67Ga-citrate scan was also performed. Normal or focal MDP uptake was obtained only in uninfected hips. Diffuse uptake of MDP was obtained only in infected hips and in one case of non-septic synovitis which also produced a false positive ILLS. A focal MDP uptake superimposed on a diffuse pattern was obtained in both infected and uninfected hips. The ILLS was abnormal in eight out of 11 cases of infection and in two out of 39 cases without infection. The 67Ga scan was abnormal in five out of six cases of infection and in five out of 26 cases without infection. It was concluded that a 99Tcm bone scan should be performed first on a painful prosthetic hip, and that for detecting infection, an ILLS was more specific but less sensitive than a 67Ga-citrate scan.

Gallium Radioisotopes↗
PubMed1985

Leucocyte and contaminant cell-bound activities resulting from the labelling of leucocytes with 111In-oxine.

A simple method is described for estimating the activities bound to leucocytes, erythrocytes, platelets and the free activity, as resulted from the preparation and labelling of leucocytes with 111In-oxine. Measurements are required only of 111In activity, suspension volumes, and platelet concentrations. The limitations of the method are discussed. When blood from a normal volunteer was labelled by an 111In-oxine manufacturer's recommended technique, the greatest proportion of activity was bound to leucocytes, and in addition, a significant proportion of the activity was found to be associated with platelets. If the number of centrifugations between sedimentation and labelling was reduced from two to one, the proportion of free activity increased at the expense of a reduction in leucocyte activity, but the platelet activity remained unchanged. The relative distribution of cell-bound and free activities was independent of the relative centrifugal force (85-450 g), and of the time (15-30 min) and the suspension volume (5-10 ml) used to incubate the cells with 111In-oxine.

Blood Platelets↗
PubMed1985

Is the skull view necessary in routine gamma camera bone scanning?

Bone scans were reviewed in 478 patients, 237 with carcinoma of the breast, 47 with carcinoma of the lung, 43 with carcinoma of the prostate, 56 with other malignancies and 95 in whom scans were performed for basic screening purposes. In only 11 of the scans reviewed were abnormalities of the skull alone observed and in only one of the 11 scans was the finding of an abnormality thought to be clinically useful. This study suggests that in patients with known malignant disease, the skull view adds little useful information. However, when performing bone scans for screening purposes, the skull view may well give helpful information.

Breast Neoplasms↗
PubMed1985

A study of leucocyte labelling efficiencies obtained with 111In-oxine.

The range of leucocyte labelling efficiencies with 111In-oxine for a group of patients extended significantly (P = 0.05) below that obtained for a series of labellings of the same normal blood from a volunteer. A retrospective analysis was made of the results in the two groups to identify the cause of this difference in range. The labelling efficiency for patients did not vary with the volume of 111In-oxine, and was independent of the whole blood leucocyte concentration. The difference between the average labelling efficiencies obtained for a group of patients and the normal series labelled by the same operator was more significant than the difference in average labelling efficiencies obtained by different operators. It was concluded that biological variation in patients' blood, rather than operator technique, must have been a more important cause to the difference in the labelling efficiency range between patients and normal. It was also concluded that variations of contaminant platelet-bound activity and of plasma viscosity were greater in the patient group than the normal series, and contributed to this difference in labelling efficiency range.

Humans↗
PubMed1984

Breast-milk radioactivity after a Tc-99m DTPA aerosol/Tc-99m MAA lung study.

Measurements were made of the concentration of Tc-99m activity in samples of breast milk following an administration of Tc-99m DTPA aerosol for a lung ventilation image and one of Tc-99m MAA for lung perfusion. The activity was 222 nCi/ml of milk (8.2 kBq/ml) at 2 hr after the MAA injection, and it was found to be excreted exponentially with an effective half-life of 4.6 hr. There was a small incorporation of Tc-99m into breast-milk protein. We conclude that the combined use of these two Tc-99m agents did not indicate the interruption of breast feeding beyond 24 hr after administration of the MAA, and that for an aerosol ventilation study alone, breast feeding need not be interrupted for more than 4 hr after the test.

Adult↗
PubMed1984

Potential radiation dose to a breast-fed infant following administration of sodium 32P-phosphate to the mother.

A 32P uptake test to diagnose an intraocular tumour was performed on a lactating woman. Breast feeding of her infant had been stopped and after injection of the 32P, a sample of breast milk on two consecutive days was collected. The concentration of 32P in the milk was greater in the second sample than the first, but it was calculated that the potential whole body radiation dose to her infant on the second day would not have exceeded 180 microSv (18 mrem).

Adult↗