PubMed Health⌕ Search

Biomedical subjects

J C Watkinson

Publications and source records attributed to J C Watkinson.

At least 55 records · Page 3Linked to original sources
PubMed1991

Metastatic carcinoma in the neck: a clinical, radiological, scintigraphic and pathological study.

This study was undertaken to compare clinical evaluation of the neck with 99mTc(v) DMSA planar scintigraphy and computerized tomography (CT) in patients with head and neck carcinoma. Twenty-six patients were studied and in all but one the neck was previously untreated. A total of 31 neck dissections were performed and the specimens examined histopathologically. CT was approximately as accurate (71%) as clinical examination (68%) and more accurate than 99mTc(v) DMSA planar scintigraphy (48%) in predicting which necks contained metastatic carcinoma. Overall, 13% of necks had their staging correctly changed by 99mTc(v) DMSA scintigraphy compared with 10% for CT. Although scintigraphy upstaged 13% of clinically N0 necks compared to 6% for CT, it was less sensitive and specific than either clinical examination or CT. 99mTc(v) DMSA planar scintigraphy has no role to play in the investigation of patients with metastatic carcinoma to include the clinically N0 neck.

Adenocarcinoma↗
PubMed1991

Metastatic squamous carcinoma in the neck: an anatomical and physiological study using CT and SPECT 99Tcm (V) DMSA.

Technetium-99m (99Tcm) (V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent that has been used to image squamous cell carcinoma (SCC) of the head and neck. This study has been undertaken to compare clinical examination with computed tomography (CT) (anatomical) and SPECT 99Tcm (V) DMSA (physiological) imaging in the evaluation of metastatic SCC of the neck. Twenty-five patients with head and neck cancer were studied. Computed tomography was as sensitive but more accurate than clinical examination in predicting the presence of cancer. SPECT 99Tcm (V) DMSA was inferior to both techniques in identifying metastatic disease. There is no role for SPECT 99Tcm (V) DMSA imaging in the management of patients with SCC metastatic to the neck. Combined imaging with CT offered no advantages over anatomical imaging with CT alone. There is no role for CT in the routine evaluation of the clinically N0 neck and the role of CT of the neck in the management of patients with metastatic SCC is discussed.

Adult↗
PubMed1991

The pharmacokinetics and biodistribution of technetium-99m(V)dimercaptosuccinic acid in an animal tumor model.

This study used an established rabbit tumor model with squamous carcinoma to evaluate the pharmacokinetics and biodistribution of technetium-99m-(V)dimercaptosuccinic acid. A total of 54 rabbits were studied (25 with no tumor; 29 with tumor). Technetium-99m(V)dimercaptosuccinic acid had a bi-exponential blood clearance in rabbits with no tumors (28 and 325 min) and in rabbits with tumors (27 and 352 min). There was no significant difference (p greater than 0.05) in mean clearance times between the two groups and clearance appeared unaffected by tumor mass. Technetium-99m(V)dimercaptosuccinic acid had a bi-exponential cumulative urine excretion with no apparent difference in half-times between non-tumor and tumor rabbit groups (200 and 240 min, respectively). Technetium-99m(V)dimercaptosuccinic acid had a major organ biodistribution in rabbits which included bone, kidneys, bladder and the blood pool. The major route of excretion was via the urine. There was no significant difference (p greater than 0.05) in organ biodistribution between rabbits with no tumors and rabbits with tumors and there was no evidence of active uptake of technetium-99m(V)dimercaptosuccinic acid by either squamous carcinoma or inflammatory tissue.

Animals↗
PubMed1991

Experience in the surgical management of medullary thyroid carcinoma.

The management of 12 patients with medullary thyroid carcinoma is reviewed. All patients underwent total thyroidectomy. Local nodal and extracapsular spread was aggressively resected, followed by radiotherapy. No patient died from uncontrolled local disease. Prolonged survival after radical treatment is demonstrated even in the presence of distant metastases.

Adult↗
PubMed1990

Scintigraphic evaluation of glomus tumours.

The current investigations of choice for a suspected glomus tumour are either direct or indirect angiography to include digital subtraction followed by computerized tomography (CT) or magnetic resonance imaging (MRI) or, if available, CT and MRI with gadolinium alone. Although these modalities confirm the diagnosis and give anatomical information to facilitate accurate staging, they do not provide functional data. The use of radionuclide scintigraphy can add an extra physiological dimension to glomus tumour imaging. Iodine-131/123 metaiodobenzylguanidine (MIBG) is a tumour imaging agent which has been used to diagnose head and neck neuroendocrine tumours to include paragangliomata and medullary carcinoma of the thyroid (MCT). However, it is expensive and the new head and neck tumour imaging agent technetium-99 m (Tc99m) (v) dimercaptosuccinic acid (DMSA) has superceded it as the imaging agent of choice to evaluate MCT. We report a patient with a glomus jugulare tumour which was evaluated with I131/I123-MIBG and Tc99m (v) DMSA. The tumour was functional and is the first reported case exhibiting positive accumulation of both I131-MIBG and Tc99m (v) DMSA. The patient was subsequently treated with a therapeutic dose of I131-MIBG. The significance of these results is discussed.

3-Iodobenzylguanidine↗
PubMed1990

Technetium-99m(v) dimercaptosuccinic acid planar scintigraphy in head and neck cancer: clinical, scintigraphic and radiological study.

Technetium-99m (Tc99m)(v) Dimercaptosuccinic Acid (DMSA) is an imaging agent which has been proposed as a scintigraphic marker for head and neck squamous cell carcinoma. Fifty-four patients were studied of whom 51 had a head and neck tumour. All patients were examined and then imaged using Tc99m(v) DMSA scintigraphy and computerized tomography. Scintigraphy was less sensitive than clinical examination in the detection of patients with cancer, patients with primary tumours and patients with metastatic neck disease. CT was as sensitive and as accurate as clinical examination but more sensitive than Tc99m(v) DMSA in detecting patients with cancer and with primary tumours. CT was more sensitive and more accurate than both clinical examination and Tc99m(v) DMSA scintigraphy in predicting which patients had metastatic neck disease. Although Tc99m(v) DMSA is accumulated by squamous cell carcinoma, its inability to detect low volume disease and apparent low specificity means it has no role to play in the management of patients with head and neck squamous cell carcinoma.

Adult↗
PubMed1990

99Tcm (v) DMSA and 67Ga-citrate imaging in patients with head and neck squamous carcinoma: a clinical and scintigraphic study.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to image medullary carcinoma of the thyroid and squamous cell carcinoma (SCC) of the head and neck. This study was undertaken to compare planar scintigraphy in patients with head and neck SCC using 99Tcm (v) DMSA and the established tumour imaging agent gallium-67 citrate (67Ga). Seventeen patients were studied of whom 16 had a head and neck malignancy. Clinical examination was more sensitive and accurate than 67Ga scintigraphy, which in turn was more sensitive and accurate than 99Tcm (v) DMSA in detecting patients with cancer, patients with primary tumours and patients with metastatic neck carcinoma. Neither 67Ga or 99Tcm (v) DMSA planar scintigraphy has any role to play in the routine evaluation at presentation of patients with head and neck SCC.

Adult↗
PubMed1990

99Tcm (v) DMSA: the pituitary sign.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate head and neck tumours. It has a normal head and neck biodistribution to include the lacrimal glands, nasal mucosa and the blood-pool. Seventy-seven patients were studied of whom 63 had a head and neck malignancy. Of these patients, 19 (25%) exhibited positive accumulation of radioactivity in the region of the pituitary gland and this was a constant finding in those followed-up after treatment. Biodistribution studies in forty New Zealand white rabbits confirmed pituitary accumulation of 99Tcm (v) DMSA. The pituitary gland region should be included in the normal biodistribution of 99Tcm (v) DMSA.

Adult↗
PubMed1990

Pharmacokinetics, biodistribution and dosimetry of 99Tcm(V)DMSA in humans with squamous cell carcinoma.

Technetium-99m (99Tcm)(V) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to evaluate squamous carcinoma (SCC) of the head and neck. This study evaluated the pharmacokinetics and biodistribution of 99Tcm(V)DMSA in patients with SCC and calculated the bone mass of a New Zealand White (NZW) rabbit. This data was then used to calculate the effective dose equivalent in man. A total of 16 patients were studied (5 with no tumour, 11 with tumour). 99Tcm(V)DMSA had a fast bi-exponential blood clearance in patients with no tumour (30 and 401 min) and patients with tumour (30 and 387 min) with no significant difference (p greater than 0.05) between the two groups. 99Tcm(V)DMSA had a fast cumulative urine excretion with mean half-times in non-tumour and tumour patients of 183 min and 244 min respectively. There was no significant difference (p greater than 0.05) between these two latter groups. The effective dose equivalent of 99Tcm(V)DMSA in man is 5.1 microSv/MBq.

Aged↗
PubMed1990

Subcellular biodistribution of 99Tcm(V) DMSA in squamous carcinoma: a comparative study in humans and in an animal tumour model.

Technetium-99m(99Tcm) (V) dimercaptosuccinic acid is a new imaging agent which has been used to evaluate head and neck squamous cell carcinoma (SCC). This study compared the subcellular biodistribution of 99Tcm(V)DMSA in an established rabbit tumour SCC model and in humans with head and neck SCC. In rabbits, approximately 17-37% of radioactivity was located on tumour cell membrane. Approximately 57-80% of radioactivity was located nonspecifically in tumour cytosol, only 2-6% was bound specifically to tumour mitochondria, and 1-4% bound specifically to microsomes. In humans, 25-45% of radioactivity was localized on tumour cell membrane and 28-60% localized nonspecifically in tumour cytosol. There was 11-20% of radioactivity specifically bound inside the cell to the mitochondria and 1-6% specifically bound to microsomes. These results show that although 99Tcm(V)DMSA is accumulated at sites of SCC, the localization process is nonspecific.

Aged↗
PubMed1990

The reliability of palpation in the assessment of tumours.

There is now a joint UICC-AJC classification for cervical lymph nodes based mainly on the size of the nodes. There is a recognized error in palpation, not only for detecting the presence of tumour but also its size. This study used an animal tumour model system to compare the ability of 6 independent observers of varying experience to detect and stage superficially transplanted growths. A preclinical medical student was as good as a Consultant ENT Surgeon in predicting the presence of tumour but the ability to stage tumours accurately was related to experience. Whilst the most experienced observers accurately estimated the size of tumours less than 2 cm, they were less accurate for larger (greater than 2 cm) tumours which were constantly understaged. This phenomenon may have important clinical implications particularly related to current nodal staging criteria.

Animals↗
PubMed1990

Nuclear medicine in otolaryngology.

Nuclear medicine has a distinct role to play in otolaryngological practice. Accurate diagnosis of endocrine conditions is now possible using precise in-vitro hormone measurement. Specific clinical questions can be answered using in-vivo investigations. 99mTcO-4/123I scintigraphy is used to evaluate thyrotoxicosis and solitary thyroid nodules. 99mTc/201T1 subtraction scanning is of value in the preoperative localization of parathyroid adenomas and 99mTcO-4 is particularly useful in assessing salivary and lachrymal gland function and drainage. 99mTc-MDP bone scanning is useful in the evaluation of osteomyelitis, temporomandibular joint dysfunction, bone graft viability and some facial fractures. The role of radioisotopes in the management of differentiated and medullary carcinoma of the thyroid is now well established. Although there are many other agents available to image head and neck cancer, few can actually achieve the required diagnostic sensitivity and specificity. The introduction of monoclonal antibodies into routine imaging has been hampered by distinct practical problems and the search is now on for more sensitive non-specific diagnostic agents. It is now possible to evaluate new 99mTc labelled tumour-imaging agents using animal tumour model systems and the use of radioactivity in all aspects of otolaryngological research adds an extra quantitive dimension. Together with SPECT, and the introduction of positron emission tomography (PET) to image the physiology of normal tissues and tumours, the use of radionuclide investigations can lead only to an increase in ENT diagnostic sensitivity and specificity and, subsequently, to an overall improvement in the way we diagnose, stage and treat head and neck cancer.

Carcinoma, Squamous Cell↗
PubMed1990

Technetium-99m (v) dimercaptosuccinic acid: a clinical and scintigraphic study in an animal tumour model.

Technetium-99m (99mTc) (v) dimercaptosuccinic acid (DMSA) is a new tumour-imaging agent which has been used to image head and neck squamous carcinoma. This study used an established rabbit tumour model to compare palpation versus planar scintigraphy in the detection of superficially transplanted cancers. Palpation detected 83% of tumours measuring less than 2 cm compared with 58% for scintigraphy. Overall, the sensitivity for palpation was 88% (77% specificity) compared with 50% (63% specificity) for scintigraphy.

Animals↗
PubMed1990

99Tcm (v) DMSA: a clinical, planar and SPECT study to evaluate patients with head and neck squamous carcinoma.

Technetium-99m (99Tcm) (v) dimercaptosuccinic acid (DMSA) is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. This study was undertaken to compare planar versus SPECT 99Tcm (v) DMSA scintigraphy in patients with head and neck SCC. Thirty-four patients were studied. Twenty-eight had SCC, and of these, four had received previous treatment with surgery or irradiation. SPECT was as sensitive and as accurate as clinical examination (but more sensitive and accurate than planar scintigraphy) in detecting which patients had cancer and which patients had primary tumours. SPECT was more sensitive and more accurate than planar scintigraphy (but less sensitive and accurate than clinical examination) in detecting lateral neck compartments with metastatic carcinoma. SPECT correctly upstaged 6% of clinically N0 necks. Although SPECT 99Tcm (v) DMSA scintigraphy improved the image quality, sensitivity and spatial resolution of the investigation, it has no role to play in the routine evaluation of patients with head and neck SCC (to include the clinically N0 neck).

Adult↗
PubMed1989

What is the optimal imaging time for 99Tcm-(V)-DMSA planar scintigraphy in the detection of squamous carcinoma? A comparative study in humans and in an animal tumour model.

99Tcm-(V)-DMSA is a new tumour imaging agent which has been used to image squamous cell carcinoma (SCC) of the head and neck. There have been, however, no studies to date evaluating its optimal imaging time for SCC. Seven patients were studied (six SCC; one nontumour) and seven rabbits (six with SCC, (17 tumours); one nontumour). For the human qualitative studies there was a 67% sensitivity at 2, 4 and 6 h with image quality being optimum at 4 h. Maximum quantitative uptake occurred between 2 and 4 h. For the rabbit qualitative studies the optimum imaging time was 4 h (92% sensitivity, 100% specificity) and maximum quantitative uptake occurred at between 1.5 and 5 h. Taking into account the human and rabbit qualitative and quantitative studies combined with the pharmacokinetics and biodistribution of 99Tcm-(V)-DMSA, the optimum imaging time of 99Tcm-(V)-DMSA in humans with SCC was between 2 and 4 h.

Aged↗
PubMed1989

Technetium-99m (v) dimercaptosuccinic acid uptake in patients with head and neck squamous carcinoma: experience in imaging.

A recently developed imaging agent, technetium-99m (v) dimercaptosuccinic acid (99mTc (v) DMSA), has been used to assess head and neck squamous carcinoma (SCC). We have prospectively studied 62 patients of whom 53 had a histologically proven head and neck SCC. The remaining nine had benign lesions. The results of planar imaging in patients with primary disease yielded an 85% sensitivity and 78% specificity. Planar imaging in patients with cervical lymphadenopathy revealed a 59% sensitivity. Nineteen patients also had single photon emission computed tomography imaging which improved the image quality, spatial resolution and sensitivity of the investigation. Twenty-seven patients were scanned before and after radiotherapy and, of these, 96% showed positive uptake in the salivary glands with no evidence of tumor recurrence. This study has shown 99mTc (v) DMSA imaging provides a cheap and rapid method of investigating head and neck SCC and further studies are necessary to evaluate its role in the management of patients with this disease.

Adult↗