Radiation doses in the surroundings of patients undergoing nuclear medicine diagnostic studies

Dose rate measurements were performed at 0, 0.5, and 1 m from the external surface of 79 patients corresponding to the most frequent studies: 99mTc-cardiac with reinjection, 99mTc-cardiac single injection, 99mTc-bone scan, 99mTc-lung studies, and cardiac studies using 201Tl. Doses to staff, nearby patients, and the collective effective doses were estimated for the different working shifts and hospital areas. The estimated dose for nurses for 1 y was 518 microSv in the cardiology section and 338 microSv in the short stay section. For patients, the mean dose per stay was calculated to be 8.5 microSv in the cardiology section. The maximum dose that a patient could receive from a radioactive patient is 499 microSv for a double injection cardiac patient study. The maximum collective effective dose for the whole hospital was calculated to be 0.063 person-Sv. The probability of staff receiving doses higher than the limits for a working day is negligible. Maximum doses for staff and patients are far below dose limits for the public and therefore no additional radiological protection is needed.

[Graft viability of patients with renal transplantation from non heart beating donors]

INTRODUCTION

Renal transplantation (RT) is currently the treatment of choice in end-stage renal disease. The Gregorio Marañón hospital performed 65 RT, 97.01 pmp, this year.

OBJECTIVE

To study the characteristics which RT patients from non-heart beating donors have in the immediate post-transplantation renogram. To know the evolution of the renal function, by renogram.

METHODS

Ten patients with NHBD graft out of 65 patients with RT were studied in the year 2003.

RESULTS

The study is made up of 10 patients with RT from NHBD, with an average timing of warm ischemia of 35 min and average timing of cool ischemia 21 h. In the post-transplantation renal function study, 9 of then showed hemodilution and one an acute tubular necrosis (ATN) pattern. In most of the cases, the study was performed the day after the RT except for one that was performed on the 4th day (1.7 +/- 1 days). Renal perfusion was conserved in every case. The renal graft maintained this type of record until post-RT day 7 (6.67 +/- 0.57 days) and evolved towards ATN after day 10 (11.65 +/- 1.5 days) and normal range on day 55 +/- 51.1 post-transplantation. All patients supported the graft, with acceptable renal function, except one of then who was treated with transplantectomy due to a renal venous thrombosis.

CONCLUSION

The renal function study showed "hemodilution" in the first post-transplantation in 90 % of the RT from NHBD. Evolution went from ATN to normality. The NHBD are adequate for transplantation, significantly shortening the waiting time for RN.

Regularity in irregular echinoids

Using the mathematical concept of eutactic star, we prove that it is possible to define a morphospace for irregular echinoids by using a single parameter. In particular, we have found an extraordinary geometric property in the flower-like patterns of the five ambulacral petals of these animals. This property is fulfilled with great accuracy for a large collection of fossil specimens and provides new insights in the study of the viable skeletal designs of extinct and/or living organisms.

[Hemarthrosis as a hemorrhagic complication after thrombolytic treatment]

Hemorrhage of variable severity is the main complication of thrombolytic treatment. We present the case of a rare hemorrhagic location after the use of this treatment for acute myocardial infarction, as ankle hemarthrosis. In the first twelve hours the patient had a joint hemorrhagic effusion with refractory pain and arthrocentesis was required. Recurrence occurred while receiving heparin and after discontinuation of heparin perfusion stopped the patient developed occlusion of the coronary artery related to the infarct requiring emergency angioplasty. We discuss the severity and possible treatment of this situation.

[Utility of SPECT with 99m Tc-tetrofosmin and stimulus with dipyridamole in patients with permanent ventricular pacemakers]

BACKGROUND AND OBJECTIVE

Patients with permanent ventricular pacemakers (PP) are a difficult subgroup to assess in the study of coronary artery disease. The objective of this study was to evaluate the diagnostic value of the myocardial perfusion scintigraphy with 99mTC-Tetrofosmin (Tc-Tf) and stimulus with dipyridamole in patients with PP and suspected coronary artery disease.

PATIENTS AND METHODS

Fourteen patients with suspected coronary artery disease and without structural cardiopathy, who underwent Tc-Tf and cardiac catheterization, were studied retrospectively. Sensitivity, specificity, predictive values and Kappa index were calculated for the diagnosis of coronary artery disease, multivessel disease, and for each one of the coronary arteries (left anterior descending, right coronary, and circumflex). In addition, the correlation between the number of territories with perfusion defects and the number of diseased vessels was studied.

RESULTS

In regards to the diagnosis of coronary artery disease, sensitivity, specificity, positive predictive value, negative predictive value and the Kappa index were 100%, 50%, 83%, 100% and 0.55, respectively. For multi-vessel disease, these values were 83%, 64%, 64%, 83% and 0.43 respectively. The correlation coefficient between the number of territories with perfusion defects and the number of diseased vessels was 0.61 (p = 0.02). In the diagnosis of anterior descending disease, sensitivity and specificity were 83% and 88% respectively. For the right coronary artery, these values were 100% and 44% and for the circumflex artery 38% and 83%, respectively.

CONCLUSION

In patients with PP and suspected coronary artery disease, myocardial perfusion scintigraphy with Tc-Tf and stimulus with dipyridamole is of great value in the diagnosis of coronary artery disease and in the assessment of its extension.

[Meaning of clinical and electrical positivity in the myocardial perfusion scintigraphy during the administration of dipyridamole]

BACKGROUND AND OBJECTIVES

Administration of dipyridamole produces angina and ST depression in 20%-30% and 6%-34% of patients, respectively. This study aimed to evaluate the clinical implications of the presentation of angina and/or ST depression during the administration of dipyridamole in the study of coronary heart disease by myocardial perfusion SPECT (MPS).

METHODS

The study population is constituted by 593 consecutive patients without left branch block or ventricular pacemaker rhythm who were referred to our service to undergo MPS with dipyridamole. A SPECT was performed after the administration of 99mTc-tetrosfosmine and drug stimulation with dipyridamole (0.142 mg/kg/min for 4 minutes). A coronariography was performed in 338 patients (57%). The frequency of clinical and electrical positivity and their relationship with the MPS and the coronariography were studied.

RESULTS

The rate of angina and ST depression was 32% (n = 190) and 10% (n = 58), respectively. Myocardial perfusion defects were observed in 465 patients (78%), and signs of scintigraphic ischemia in 311 (52%). The patients with ST depression presented a higher frequency of perfusion defects (93% vs 76%, p = 0.0012) and scintigraphic ischemia (89% vs 49%, p < 0.0001). In addition, perfusion defects in more than one territory were observed in these patients in a higher percentage (53% vs 34%, p = 0.0036). Among the patients who underwent cardiac catheterization, those who had a ST depression had a greater extension of coronary heart disease (1.8 +/- 1.2 vs 1.3 +/- 1.0 diseased vessels, respectively. p = 0.0100) and a higher frequency of multivessel disease (61% vs 43%, p = 0.0380). Those patients who had clinical positivity showed a scintigraphic ischemia more frequently (66% vs 47%, p < 0.0001), however no statistically significant differences were observed between the presence of patients with perfusion defects or in the extension of these defects as well as in the number of diseased vessels in the coronariographic study.

CONCLUSIONS

During the administration of dipyridamole, the ST depression is associated with more frequent scintigraphic ischemia, larger extension of perfusion defects and more diseased vessels. The appearance of angina is associated with scintigraphic ischemia, but it is not necessarily associated with the extension of perfusion defects or greater number of diseased vessels.

[Bone scintigraphy findings in patients with recently diagnosed adenocarcinoma of the prostate: relationship with prostate specific antigen levels]

BACKGROUND AND OBJECTIVES

Although it has been suggested that bone scintigraphy (BS) may not be necessary in patients with prostate adenocarcinoma (PA) and normal prostate specific antigen (PSA) plasma levels, controversy still remains. The objective of the study was to evaluate the existing relationship between PSA plasma levels and BS findings in patients with a recently diagnosed PA in order to assess whether BS may be omitted on the basis of the PSA levels in these patients.

METHODS

The 475 patients (70+/-7 years old) consecutively diagnosed of PA between 1994 and 1998 in our institution made up the study population. PSA plasmatic levels were determined and BS was performed (body planar study after 99mTc-methyl diphosphonate 900 MBq administration) in all the patients.

RESULTS

In 362 patients (76.2%), BS was negative, in 108 (22.7%) positive and undetermined in the remaining 5 patients (1.1%). The mean PSA level in the whole study population was 74+/-267 ng/ml (range 0.4-4.200) and was higher in patients with positive GO (218+/-512 vs 31+/-89, p<0,0001). As PSA increased, the rate of patients with positive BS was significantly higher, this being 0%, 16.4%, 9.7%, 14.0%, 31.0% and 48.3% in patients with PSA 4, 4.1-10; 10.1-20; 20.1-30; 30.1-40, and >40 ng/ml, respectively (p<0.0001). In patients with positive BS, the PSA levels were 20 and 10 ng/ml in 30.6% and 18.6% of the patients, respectively.

CONCLUSION

According to our experience, there is a significant association between PSA plasma levels and the BS results in patients with recently diagnosed PA. However, a significant proportion of patients with bone metastasis have normal PSA levels, and therefore BS should be performed in all patients with recently diagnosed PA regardless of the PSA levels.

[Results of myocardial scintigraphy with 99mTc-tetrofosmin and dipyridamole administration in patients diagnosed of microvascular angina]

The objective of the study was to evaluate the results of the myocardial scintigraphy with 99mTc-tetrofosmin (Tc-Tf) and pharmacological stimulation with dipyridamole in patients diagnosed of microvascular angina. The study population is made up of 50 patients discharged with the diagnosis of microvascular angina who had undergone Tc-Tf-dipyridamole. Clinical and electrical positivity appeared in 40% and 12% of the patients, respectively. Myocardial perfusion defects were found in 35 patients (70%), and were reversible in 21 (60%), fixed in 11 (21%), and combined in 3 (9%). Abnormalities were inferior, anteroseptal and lateral in 21, 18, and 2 patients, respectively. Patients with a positive exercise treadmill test, compared with those with a negative one, had more frequent perfusion abnormalities (91% vs 50%, p = 0.0327) and myocardial ischemia (64% vs 20%, p = 0.392). Women, in comparison with men, had angina (56% vs 22%, p = 0.013), and anteroseptal perfusion abnormalities (26% vs 4%, p = 0.028) more frequently. On the contrary, men had inferior perfusion abnormalities more frequently (57% vs 30%, p = 0.057). Thus, Tc-Tf-dipyridamole shows perfusion abnormalities in 70% of patients with microvascular angina (91% in patients with a positive exercise treadmill test). Scintigraphic pattern may be partially conditioned by gender in these patients.

[Usefulness of spect with 99mTc-tetrofosmin and stimulus with dipyridamole in patients with left bundle branch block of His]

BACKGROUND

In patients with left bundle branch block, the 201Tl scintigraphic studies show high sensitivity, but with low specificity, in the diagnosis of coronary artery disease.

OBJECTIVE

[corrected] To assess the value of 99mTc-tetrofosmin Single Photon Emission Computed Tomography (SPECT) and dipyridamole administration in patients with left bundle branch block.

METHODS

22 patients with angina and left bundle branch block were retrospectively studied by cardiac catheterization and Tc-Tf after dipyridamole administration (0,142 mg/kg/min. i.v.) and at rest.

RESULTS

The mean number of territories with perfusion defects was 1.5+/-1.0, and the average number of diseased vessels in the coronariographic study was 1.6+/-1.3 (r = 0.77, p<0.001). Sensitivity, specificity, positive predictive value, negative predictive value, total predictive value and Kappa index in the diagnosis of multivessel disease were 92%, 90%, 92%, 90%, 91% and 0.82, respectively. In the diagnosis of anterior descending artery disease, these values were 83%, 70%, 77%, 78%, 77%, and 0.54, respectively.

CONCLUSION

In patients with angina and left bundle branch block, SPECT with Tc-Tf-dipyridamole is of great value in the study of coronary artery disease extension. Sensitivity and specificity for the diagnosis of anterior descending artery disease were similar to that shown in series with thallium-dipyridamole.

[Scintigraphy diagnosis of renovascular hypertension in renal transplanted patients]

Captopril renography (CR) has been shown to be a useful technique in the diagnosis of renovascular hypertension (RVH). This disease is a significant complication of the kidney transplanted patient so that early diagnosis would be extremely useful to preserve renal function and prevent graft loss. This work evaluates the role of CR, together with arteriography and doppler-ultrasound, in the diagnosis of RVH.

MATERIALS

A total of 19 transplanted patients with clinical suspicion of RVH underwent an isotopic study, a doppler-ultrasound study and an arteriography. Scintigraphy was performed 1 hour after a 50 mg dose of captopril, with oral hydration and i.v. administration of approximately 111 MBq of 99mTc-MAG3 and 20 mg of furosemide. If abnormal, a subsequent renography in baseline conditions was performed for comparison.

RESULTS

Overall, 11 patients had renovascular hypertension. Sensitivity and specificity of CR were 91% and 80% respectively, 100% and 60% for US and 91% and 100% for arteriography. The CR yielded one false positive result and 2 false negatives cases: one with 50% stenosis and one polar artery stenosis. Six patients were successfully dilated or operated.

CONCLUSION

CR seems to be a reliable diagnostic tool for the diagnosis of renovascular hypertension in kidney transplanted patients.

Bilateral massive edema of the ovary

We present a case of synchronic bilateral ovary mass edema. In spite of the patient's age and the difficulties of the intraoperative study it reveals a high likelihood of malignancy in the preoperative stage.

[Surgery unit for epilepsy]

INTRODUCTION

Only few medically refractory epileptic patients are evaluated for surgical treatment, in spite of the good results obtained at the Centers where epilepsy surgery is performed.

OBJECTIVE

We are presenting the way the Gregorio Marañón Hospital Epilepsy Surgery Unit functions and their casuistry.

PATIENTS AND METHODS

This Unit is composed by members of the Services of Neurosurgery, Neurology, Neurophysiology, Neuroradiology, Psychology, Neuropediatry, Nuclear Medicine and Neuroanestesiology. Patients are studied by means of protocols.

RESULTS

Twenty cases were operated upon. The procedures were temporal lobectomy in 9 cases, amygdalo-hipocampectomy in 4, frontal lobectomy in 3, frontal topectomy in 2, partial hemispherectomy in 1 and vagal nerve stimulation in 1. In 16 of the 19 surgery specimen there were some pathological abnormalities. In the short follow-up 13 patients are seizures free experience significant improvement.

[Kinetic assessment of salivary secretory response to citric acid. Differences with pilocarpine]

BACKGROUND

Induction of salivation is becoming increasingly popular in the assessment of salivary gland status. Various mechanical or pharmacological procedures are empirically used to produce salivation. Oral stimulation by citric acid (AC) is by far the most used sialagogue procedure.

AIM

To characterize the salivary secretory response to AC solutions applied to the dorsolateral tongue surfaces.

SUBJECTS AND METHODS

Young healthy women from the upper levels of a medical career (n = 19) participated as volunteers. Salivary volume and UV-absorbing organic material in saliva from single subjects were measured after various protocols of topical stimulation by AC.

RESULTS

After a single stimulation by 1-8% AC the salivary flow rate peaked before 30 seconds and recovered the basal level earlier than 2 minutes. Repetitive stimulations at 30-sec intervals kept the flow rate at a maximum. After suspending these stimulations, basal flow rate was recovered before 2 minutes. Repetitive AC-stimulations at 8-min intervals produced a series of identical and independent secretory responses. The concentration of organic material in saliva remained unaltered after the various modes of stimulation. Thus, the profile of organic material secretion was always a direct expression of changes in salivary flow rate. In contrast to AC, the oral administration of the cholinergic agonist pilocarpine (PIL) produced a two-wave salivary response that as a whole lasted for about 30 minutes. In this case the volume and the amount of organic material were at least 10-fold the ones secreted in response to AC.

CONCLUSIONS

AC provoked a rapid and short-lived salivary response that differs markedly from the one produced by other secretagogues, like pilocarpine.

Clinical, histopathological, cytogenetic and prognostic differences between mucinous and nonmucinous colorectal adenocarcinomas

OBJECTIVE

To assess the clinical and biological significance of histological typing of colorectal carcinomas.

PATIENTS AND METHODS

The retrospective analysis of 142 consecutive patients who underwent surgical resection of a mucinous (MC; n = 27; 19%) or a nonmucinous (nMC; n = 115; 81%) colorectal adenocarcinoma was carried out. The two groups were compared in terms of the clinical features, p53 gene expression (antiserum CM1), proliferating cell nuclear antigen (PCNA) labeling index, DNA ploidy (by flow cytometry), histopathological features, prognosis and recurrence rate.

RESULTS

The two types of tumors differed with respect to patient age, location, morphology, pattern of genetic lesions and type of tumor recurrences. Twenty-five percent of the patients with MC and 9% of those with nMC (p = 0.04) were under 50 years of age. The incidences of right MC and left MC were similar, while the majority of the nMC were located on the left side (p = 0.04). The MC were of higher grade and their margins more infiltrative than those of the nMC (p = 0.001 and p = 0.01, respectively), p53 nuclear staining was observed less frequently in the MC than in the nMC (30% vs 55%; p = 0.03). The PCNA labeling index was higher in the nMC (46% vs 21%; p = 0.05). We observed no significant differences with respect to tumor stage, incidence of vascular invasion or prevalence of lymphocytic infiltration. The prognosis was similar in both groups, although their recurrence patterns differed, with a tendency toward locoregional recurrence in the cases of MC.

CONCLUSION

These findings suggest that, despite their similar prognoses, these two types of lesions are epidemiologically, phenotypically and genotypically different and, thus, result from distinct carcinogenic pathways.

[Integration of multimodal medical images]

Multimodality analysis is becoming a required tool in medical practice due to the development of different image techniques and new imaging processing tools. This paper is a review of the basis of medical image integration, image fusion techniques, and their clinical applications, especially addressing our experience with brain tomographic studies in nuclear medicine and radiology.

[Devices for saliva collection from the major salivary glands. Results in normal subjects]

BACKGROUND

Collection of saliva produced by the major salivary glands may be accomplished either by cannulation of the glandular ducts or by the application of specific collecting devices to the emergence area of the glandular ducts. Those procedures are complex, slow, invasive and require skilled personnel.

AIM

To report the design and application of a device to collect parotid saliva (snail collector) and another device to collect saliva from the submandibular/sublingual complex.

MATERIAL AND METHODS

The saliva collection devices were tested in 40 healthy volunteers (20 male) aged 18 to 22 years old. Saliva was collected using conventional conditions, during 5 to 15 min.

RESULTS

An average of 1 to 1.5 ml of saliva was collected in the 10-15 min period from both parotid and submandibular/sublingual glands. Flow rates from parotid glands were 80 microliters/min and 180 microliters/min from submandibular/sublingual glands. Parotid saliva had a protein and organic material concentration twice as high than saliva from submandibular/sublingual glands. The presence of human alpha-amylase duplet (Mr 55 kD and 58 kD) predominated in parotid saliva, whereas saliva from submandibular/sublingual glands had other molecular markers such as the lysozyme duplet (Mr 18.5 kD and 17 kD).

CONCLUSIONS

The tested devices were easily applicable, comfortable and allowed the collection of both parotid saliva and submandibular/sublingual saliva from various subjects at once, under the supervision of a single professional.

Technetium-99m-HMPAO in Tourette's syndrome on neuroleptic therapy and after withdrawal

Both decreased and increased perfusion and metabolism have been described with PET and SPECT in different areas of the brain in patients with Gilles de la Tourette's syndrome. The aim of this study was to define the regional cerebral perfusion pattern in drug-free patients and the changes in perfusion with the usual neuroleptic treatment.

METHODS

A group of 13 normal control subjects and 15 unmedicated Gilles de la Tourette's syndrome patients were studied with 99mTc-HMPAO brain SPECT. Thirteen of the initial group of patients were retested on neuroleptic treatment. A semiquantitative analysis of the images was performed.

RESULTS

Decreased perfusion in orbital and anterior medial regions of both frontal lobes as well as in both temporal lobes was observed in the nontreated group compared with control subjects. With treatment, a perfusion increase in these frontal regions and in the left medial temporal cortex was observed.

CONCLUSION

Neuroleptic treatment could decrease the hyperactivity of the dopaminergic system leading to improvement of the clinical symptoms and reperfusion of some previously hypoperfused regions.