Soluble Interleukin-2 Receptors in Patients with Advanced Colorectal Carcinoma

The levels of soluble interleukin-2 receptors (sIL-2R) were measured in the serum of 52 patients with advanced colorectal carcinoma and compared to CEA and CA 19-9 levels. Twenty-five normal, age and sex-matched individuals served as controls. Seventy-five per cent of the patients had increased mean serum levels of sIL-2R (1539 ± 155 U/ml), while normal controls had mean levels of 555 ± 31 U/ml (p < 0.001). The relationship with hepatic or lymph nodal metastases showed no statistically significant difference (p=0.34 and p=0.47, respectively). Serum sIL-2R levels showed a linear correlation with CEA (p < 0.05). Patients with lower pretreatment sIL-2R levels (less than 1.200 U/ml) had a longer survival than patients with higher initial levels (more than 1.200 U/ml) (p=0.0049).

In conclusion, the present work shows that the serum levels of sIL-2R: a) are elevated in patients with advanced colorectal cancer, b) have no relationship with the type of metastases, c) correlate with serum CEA and d) have a prognostic value for survival.

Serum soluble interleukin-2 receptors in epithelial ovarian cancer patients

The levels of soluble interleukin-2 receptors (sIL-R2) were measured in the serum of 52 patients with epithelial ovarian carcinoma as well as in 25 age and sex-matched normal controls. The mean serum level of sIL-2R was increased in 37 patients (71.2%). Comparison of these levels to those of normal controls showed a highly statistically significant difference (p<0.001). Serum sIL-2R levels were not related to histology, clinical stage or the presence of ascites (p-0.58, p=0.32 and p=0.67, respectively), nor did they follow disease activity or response to chemotherapy. However, patients with higher pretreatment sIL-2R levels (more than 1200 U/ml) were found to have a longer survival (p<0.02), possibly explained by the presence of activated lymphocytes and a better immune surveillance. We conclude that the serum level of sIL-2R: a) is elevated in ovarian cancer patients, b) has no relationship with histological subtypes, tumor burden or the presence of ascites, c) cannot serve as a valuable tumor marker for the monitoring of patient treatment, and d) has a prognostic value for survival.

Serum Tumor Markers in Non-Hodgkin's Lymphomas and Chronic Lymphocytic Leukemia

The levels of soluble interleukin-2 receptors (sIL-2R), beta-2 microglobulin (β-2M), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured in the serum of 50 previously untreated patients with non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL) as well as in 25 age and sex-matched normal controls. Compared to normal controls, mean serum levels of sIL-2R and β-2M were significantly increased in both NHL and CLL (p < 0.001) while the increase in ESR and CRP was less marked (p < 0.01 and p < 0.05, respectively). Comparison of these tumor markers with histologic grading showed statistically significant differences only for CRP between low, intermediate and high-grade lymphomas (p < 0.001 and p < 0.05). More advanced stages exhibited higher mean values of all serum markers than early stages (p < 0.001 for sIL-2R, β-2M and ESR and p < 0.05 for CRP). An association with the presence of b-symptoms was observed only for sIL-2R (p < 0.05). In addition, sIL-2R as well as β-2M were able to predict time to progression in patients with diffuse large-cell lymphomas.

We conclude that of the four tumor markers tested sIL-2R and β-2M more frequently showed increased serum levels and were associated with clinical stage and/or presence of b-symptoms. Both sIL-2R and β-2M were also found to have prognostic significance for survival.

Limitations of Quantitative CT in Corticosteroid Induced Osteopenia

Single energy spectrum quantitative CT (SES-QCT) was applied for the assessment of the trabecular bone mineral status in patients under long-term corticosteroid treatment. Seventeen renal graft recipients (RGR) and 12 patients receiving corticosteroid treatment for collagen disease were studied. A reduction of about 40% in the spinal trabecular bone density relative to matched controls was found, associated with the corticosteroid administration. Repeated measurements showed significant reduction in density 4 months after transplantation, and an increase in density after graft rejection. Radiologic or clinical evidence of osteopenia in the spine was not found. Other non-invasive techniques, applied in the upper extremities of the RGR, showed only minor bone reduction compared to controls. The findings of the present study suggest that adipose tissue deposition in the spinal trabeculae can introduce errors in the measurements. Therefore, SES-QCT should not be applied during corticosteroid therapy.

Educational and training activities in personal dosimetry in Greece

An individual monitoring programme is one of the main components of any radiation protection programme since it constitutes the mean for assessing and thus optimising the doses of occupationally exposed workers. The Greek Atomic Energy Commission (GAEC) is the competent authority for radiation protection and nuclear safety in Greece. GAEC's educational and training activities in the field of occupational radiation protection at the national and regional (Eastern Europe) level are presented, along with the relevant activities of the University of Ioannina in the region of North-West Greece, as an example of a local education and training programme. The curricula of two postgraduate courses addressed to qualified experts and medical physics experts and mainly the modules dedicated to individual monitoring are discussed as well.

Evolution of a Focal Brain Lesion Produced by Interlaced Microplanar X-Rays

Stereotactic radiosurgery has led to advances in the treatment of central nervous system disease. It relies upon the principle of delivering relatively high dose irradiation to a precise target, while exposing surrounding tissues to extremely low doses. We describe a novel radiosurgical approach using interlaced microplanar X-rays which we have termed "microradiosurgery." The use of microbeams allows for 1,000-times greater precision than current clinically employed techniques. As a demonstration of this new method, we produced a approximately 3.8 mm (3) lesion in the rat brain. The lesion was followed over a period of 216 days using 9.4 Tesla magnetic resonance imaging. Our results show a gradually developing lesion at the site of the interlaced beams. The lesion began as a high T2 signal only, but advanced to include a central area of low T1 and mixed T2 signal within 2 months. No lesion was observed in the other side of the brain which was exposed to non-interlaced microbeams only. Interlaced microbeams is an effective method to create focal brain microlesions. This technique may allow the future treatment of pathology not accessible by surgical or more traditional radiosurgical means.

Multi-detector row CT urography on a 16-row CT scanner in the evaluation of urothelial tumors

The purpose of this study was to assess the role of multi-detector row CT urography (MDCTU), on a 16-row CT scanner in the evaluation of patients with painless hematuria, with emphasis placed in the detection of urothelial tumors. We retrospectively reviewed the MDCT urographies of 75 patients, referred for painless hematuria. The CT protocol included unenhanced images, obtained with a detector configuration of 16x1.5 mm and pitch of 1.2, nephrographic and excretory-phase images, obtained with a detector collimation of 16x0.75 mm and pitch of 1.2. Axial and coronal reformatted images were evaluated. Three-dimensional reformation of the excretory-phase images was performed using the volume-rendering technique. The standard of reference included clinical and imaging follow-up, cystoscopic, surgical and histologic findings. In 55 (73%) of 75 patients, the cause of hematuria was identified on MDCTU; the most common cause was urothelial cancer, including seven tumors with a diameter equal or smaller than 0.5 cm in diameter. Sixteen-row MDCTU provided satisfactory results in the investigation of patients with painless hematuria. The main advantage of the technique is its ability to detect uroepithelial malignancies.

Patient and personnel dosimetry in endovascular radiotherapy with 90Sr/90Y sources

Endovascular brachytherapy (EVBT) is an established treatment to reduce the probability of restenosis after a percutaneous coronary intervention. The purpose of this study was to assess (1) the manufacturer's stated dosimetric data for (90)Sr/(90)Y source trains to be used in EVBT and (2) the procedure-related radiation burden. The radiation fields in water around six (90)Sr/(90)Y source trains were studied using phantoms made of 'solid water' and MD55-2 radiochromic films. The water equivalence of the phantom material was tested by applying quantitative computed tomography. Thermoluminescence dosemeters were used to assess personal radiation burden and crosscheck the dose distribution along the source trains. Technical failure was observed in one source train and this train was excluded from analysis. The measured dose rate in water at 2 mm radial distance was on average 8% higher than the manufacture's stated value (range of measured to stated values 1.05--1.15). The dose rate decreased exponentially with radial distance between 2 and 6 mm. The dose rate in contact with the source viewing window of the delivery devices ranged between 0.5 and 7.5 mGy h(-1). Low-energy photons were the main contributors to personal dose.

Computed Tomographic Virtual Cystoscopy for the Detection of Urinary Bladder Neoplasms

OBJECTIVE

To evaluate the role of computed tomographic virtual cystoscopy (CTVC) in the detection of bladder neoplasms and to compare CTVC at conventional and reduced milliAmperes-second (mAs) settings.

METHODS

Twenty-four patients with known bladder neoplasms from previous conventional cystoscopy were examined with CTVC. The urinary bladder was insufflated with room air and helical CT data were obtained. Virtual images were created using volume rendering algorithms. In eight patients we used both regular (240) and reduced (70) mAs values. The lesions were recorded on transverse tomographic slices and virtual images and compared with conventional cystoscopy, operative and pathology results.

RESULTS

All bladder lesions (30) seen on conventional cystoscopy were demonstrated with CTVC. Two lesions detected on imaging studies and subsequently found at operation were not seen on conventional cystoscopy. In a third case of a neobladder, conventional cystoscopy was impossible due to neoplastic involvement of the penis. In all cases the lesions were equally conspicuous with conventional and low mAs values.

CONCLUSIONS

Computed tomographic virtual cystoscopy is a minimally invasive technique that can provide comprehensive information about urinary bladder tumors. Furthermore, low mAs studies are equally effective for the examination of such patients.

Prompt-gamma neutron activation analysis facility for in vivo body composition studies in small animals

The design, calibration, dosimetry and performance evaluation of a prompt-gamma neutron activation analysis facility for in vivo body composition studies in small animals (i.e. rats or rabbits) is discussed. The system design was guided by Monte Carlo transport calculations using MCNP-4C code. A system was built and performance evaluation was made using a 185-GBq Pu-Be neutron source. Prompt-gamma rays produced by neutron capture reactions were detected by a combination of a NaI(Tl) scintillation and a HPGe semiconductor detectors. Nitrogen and chlorine were quantified by analysis of the 10.83-MeV and 6.11-MeV peaks, respectively. Appropriate corrections for the animal body size were determined. The facility described allows the in vivo determination of protein and extracellular space in sets of experimental animals.

Effects of delayed (24 h postintervention) β-irradiation therapy after coronary angioplasty and stenting in de novo native coronary artery lesions

BACKGROUND

The effects of brachytherapy performed 24 h postintervention in de novo native coronary artery lesions.

METHODS AND RESULTS

Thirty-nine patients with 39 de novo coronary artery lesions were randomised to prompt (immediately after intervention, n=21) or delayed (24 h later, n=18) beta brachytherapy ((90)Sr/(90)Y) after been successfully revascularized with stenting. Clinical follow-up data up to 21 months (median time) were compared. After irradiation and at 6-month follow-up, paired volumetric analysis of the stented segment and the 5-mm proximal and distal reference segments was performed; this included measurements of the external elastic membrane, lumen, plaque, and media (external elastic membrane minus lumen), stent and intima hyperplasia (stent minus lumen). Baseline clinical and angiographic characteristics were similar in the two groups. Postintervention measurements of stent, lumen, and intima hyperplasia volumes as well as postintervention minimum lumen cross-sectional areas were not different. In the stented segments and in the segments 5 mm proximal and distal to the stent, similar changes of all IVUS measurements were measured in the two patient groups, but in the lumen volume at the proximal stent edge of patients irradiated 24 h postinjury. At 21 months median follow-up time, target lesion revascularization (TLR) was performed in 8 patients (38%) in the prompt irradiation group compared with 3 (17%) in the delayed (P=.17).

CONCLUSION

Beta irradiation is similarly effective whether performed immediately after percutaneous coronary intervention or 24 h later.

Could X-ray microbeams inhibit angioplasty-induced restenosis in the rat carotid artery?

BACKGROUND

Parallel, thin (<100 microm) planes of synchrotron-generated X rays, have been shown to spare normal tissues and preferentially damage tumors in animal models. The aim of the present study was to assess the effect of such microbeams directed unidirectionally on angioplasted rat carotid arteries.

METHODS AND MATERIALS

Three groups of Sprague-Dawley rats were studied: (a) rats with normal, untreated arteries, (b) rats treated by balloon angioplasty, but not irradiated, and (c) rats treated with balloon angioplasty and exposed to single fraction, unidirectional, parallel, microbeams an hour after angioplasty. The microbeam array, 15 mm widex7.6 mm high, consisting of 27-microm-wide beam slices, spaced 200 microm center-to-center laterally traversed the damaged artery. The in-depth in-beam dose was 150 Gy, the "valley" dose (dose midway between microbeams resulting mainly from X-ray scattering) was 4.5 Gy on average, and the "integrated" (averaged) dose was 26 Gy.

RESULTS

Microbeam irradiation, as given in the present study, was tolerated, but was insufficient to significantly suppress the neointimal hyperplasia.

DISCUSSION

The microbeam dose used is considered low. Dose escalation would be necessary to reach conclusive results regarding the X-ray microbeam efficacy to control restenosis.

External beam irradiation in angioplasted arteries of hypercholesterolemic rabbits. The dose and time effect

PURPOSE

To study the dose and time effect of external beam irradiation on the morphometry of both angioplasted and nonangioplasted arteries in a hypercholesterolemic rabbit model.

METHODS AND MATERIALS

Eight groups of rabbit femoral arteries were studied: arteries (a) with no intervention, (b) irradiated with a 12-Gy 6 MV X-ray dose, (c) with a 18-Gy, (d) treated with balloon angioplasty, (e) dosed with 12-Gy half an hour post-angioplasty, (f) dosed with 18-Gy half an hour post-angioplasty, (g) dosed with 12-Gy 48 h post angioplasty, (g) dosed with 18-Gy 48 h post angioplasty.

RESULTS

External irradiation at either 12 or 18 Gy was not found to change vessel morphometry in noninjured arteries. The 12-Gy dose given soon after angioplasty further increased percentage stenosis (63% on the average), despite the preservation of the lumen cross-sectional area. Positive remodeling was not observed in arteries given 18-Gy half an hour post angioplasty to counterbalance the increased neointimal formation. Therefore, this treatment resulted in a drastic reduction in lumen area and in enhancement of percentage stenosis (84% on the average). On the contrary, the delayed irradiation of the angioplasted arteries at either 12 or 18 Gy was not found to influence any of the studied morphometric parameters 5 weeks after angioplasty.

CONCLUSIONS

Uniform external beam irradiation up to 18 Gy was well tolerated by intact femoral arteries. Prompt 12- or 18-Gy irradiations accentuated percentage stenosis. However the lumen cross-sectional area was preserved only at the lower dose point. Delayed irradiation at any dose did not influence the restenosis process.

Dosimetry with radiochromic films: a document scanner technique, neutron response, applications

The possibility of reading radiochromic films by the employment of a document scanner and associated software was explored. Dosimetric characteristics, such as the sensitivity of the technique, reproducibility in dose assessment, minimum detectable dose, film uniformity, OD variation with time, variation of OD due to multiple scans, polarity of the analyzing light, fast neutron response and thermal neutron yield were investigated. The technique was used to measure dose distributions in stereotactic radiotherapy, orthovoltage treatment and neutron capture therapy.

Response of avian embryonic brain to spatially segmented x-ray microbeams

Duck embryo was studied as a model for assessing the effects of microbeam radiation therapy (MRT) on the human infant brain. Because of the high risk of radiation-induced disruption of the developmental process in the immature brain, conventional wide-beam radiotherapy of brain tumors is seldom carried out in infants under the age of three. Other types of treatment for pediatric brain tumors are frequently ineffective. Recent findings from studies in Grenoble on the brain of suckling rats indicate that MRT could be of benefit for the treatment of early childhood tumors. In our studies, duck embryos were irradiated at 3-4 days prior to hatching. Irradiation was carried out using a single exposure of synchrotron-generated X-rays, either in the form of parallel microplanar beams (microbeams), or as non-segmented broad beam. The individual microplanar beams had a width of 27 microm and height of 11 mm, and a center-to-center spacing of 100 microm. Doses to the exposed areas of embryo brain were 40, 80, 160 and 450 Gy (in-slice dose) for the microbeam, and 6, 12 and 18 Gy for the broad beam. The biological end point employed in the study was ataxia. This neurological symptom of radiation damage to the brain developed within 75 days of hatching. Histopathological analysis of brain tissue did not reveal any radiation induced lesions for microbeam doses of 40-160 Gy (in-slice), although some incidences of ataxia were observed in that dose group. However, severe brain lesions did occur in animals in the 450 Gy microbeam dose groups, and mild lesions in the 18 Gy broad beam dose group. These results indicate that embryonic duck brain has an appreciably higher tolerance to the microbeam modality, as compared to the broad beam modality. When the microbeam dose was normalized to the full volume of the irradiated tissue. i.e., the dose averaged over microbeams and the space between the microbeams, brain tolerance was estimated to be about three times higher to microbeam irradiation as compared with broad beam irradiation.

A phantom for dosimetric characterization of small radiation fields: design and use

An acrylic phantom was designed and constructed for the acquisition and verification of basic dosimetric data of narrow fields in stereotactic radiotherapy/radiosurgery (SRT/SRS) using thermoluminescent (TL) dosimetry. An array of holes to accommodate up to 426 dosimeters was used to allow the assessment of dose distribution in circular fields with a 1-mm spatial dose resolution with minimal field perturbation. It was found experimentally that there must be a minimum gap of 1 mm between neighboring dosimeters in 6-MV photon fields. Most of the dosimetric characteristics of a 6-MV x-ray SRS/SRT unit assessed using TL dosimetry and ion chamber dosimetry were in good agreement when the longitudinal axis of the chamber was parallel to the central beam axis. TL dosimetry showed that the penumbra width increased with increasing collimator aperture. The low cost of the phantom and the widespread use and familiarity of TL dosimetry in radiotherapy departments offer a significant advantage in the use of the proposed methodology.

Blueberry juice used per os in upper abdominal MR imaging: composition and initial clinical data

The aim of this study was to evaluate the use of a commercially available blueberry juice (BJ) both as a positive and negative oral contrast agent and to present the exact contents of paramagnetic ions. The concentration of Mn and Fe were determined in tinned myrtilles in syrup (atomic absorption). Nine healthy volunteers and 12 patients (age range 20-65 years) were examined using a 1-T MR scanner before and after per os administration of 430 ml of BJ. A qualitative analysis of signal alterations in the stomach, duodenum, and proximal small intestine was performed. In addition, a quantitative analysis was assessed in terms of signal-to-noise ratio calculation. The mean concentration (x +/- SD) of the ions found in the content of the three cans were 3.3 +/- 0.4 microg/g for iron and 20.6 +/- 2.6 microg/g for manganese. Based on the qualitative evaluation, signal alteration on T1-weighted images after administration of BJ was statistically significant in the stomach and duodenum, but not in the proximal small bowel. Signal alteration on T2-weighted images was not statistically significant in any part of the gastrointestinal tract. The quantitative analysis of the T1- and T2 shortening showed that BJ is efficient with only T1-weighted sequences, and this applied to the stomach, duodenum, and proximal small bowl. Blueberry juice can be used as an oral contrast agent in upper abdominal MR for T1-weighted imaging.

External beam irradiation following balloon angioplasty in an atherosclerotic rabbit model

PURPOSE

To study the effect of external beam irradiation on the morphometry of both angioplasted and nonangioplasted arteries in a hypercholesterolemic rabbit model.

METHODS AND MATERIALS

Four groups of rabbit femoral arteries were studied: arteries (a) with no intervention, (b) irradiated with a 12-Gy x-ray dose, (c) treated with balloon angioplasty, and (d) dosed with 12 Gy 30 min after balloon angioplasty.

RESULTS

External irradiation did not change vessel morphometry in nonangioplasted arteries. On the contrary, it induced neointimal formation and decreased luminal area, without causing any vessel remodeling in arteries treated with balloon angioplasty.

CONCLUSION

External irradiation at 12 Gy given 30 min after angioplasty in the studied model accentuated the neointimal response to vascular injury, without causing any vessel remodeling.

The effects of boron neutron capture irradiation on oral mucosa: evaluation using a rat tongue model

The ventral surface of the tongue of male Fisher 344 rats was used to evaluate the response of oral mucosa to boron neutron capture irradiation. Three hours after i.p. injection of 700 mg/kg of the boron delivery agent p-boronophenylalanine (BPA), the boron concentrations in blood and tongue mucosal epithelium were approximately 21 and 23 microgram (10)B/g, respectively. The doses required to produce a 50% incidence of ulceration with X rays, the Brookhaven Medical Research Reactor thermal neutron beam alone, or the thermal neutron beam in the presence of BPA were 13.4 +/- 0.2, 4. 2 +/- 0.1, and 3.0 +/- 0.1 Gy, respectively. Ulceration of the tongue was evident by 6 to 7 days after irradiation, irrespective of the irradiation modality; healing was related to dose and was relatively rapid (</=19 days). Compared to 100 kVp X rays, the relative biological effectiveness factors were 3.2 for the thermal neutron beam and 4.9 for the products of the boron neutron capture reaction, (10)B(n,alpha)(7)Li. Oral mucosa is highly sensitive to BPA-mediated BNC irradiation and could be a dose-limiting normal tissue in BNCT of brain tumors, or if BPA-based BNCT is applied to the treatment of head and neck tumors.

A case report on two primary malignancies of the ovary and kidney

Multiple primary malignant tumors in the same patient are very rare. Moreover, cases with primary ovarian and renal cell carcinoma in the same patient is an extremely rare phenomenon. In this report, a case with these two primaries is described. Concomitantly, some data suggesting a relationship of these primaries with the hypothesis of hormone dependency of renal cell carcinoma is presented.

CT measurement of lung density

PURPOSE

The aim of this study was to obtain more accurate data on the electron density of the lungs in healthy subjects and to determine the factors that influence this value.

MATERIAL AND METHODS

Single kVp quantitative CT was applied in 130 normal adults (61 men and 69 women) to study the electron density of the lung.

RESULTS

The electron density of the lung in men was lower than that in women. In contrast, the area designated as lung in men was larger than that in women. The mean electron density decreased with increasing age in men, but not in women. The following parameters were not found to influence lung electron density: body mass, body height, smoking habits, and right or left lung. The electron density of the lung medial to the thoracic wall and close to the breast was lower than the density in the entire lung parenchyma.

CONCLUSION

Quantitative CT provided the means to study noninvasively the electron density of the lung and the factors that influence this value.

Bone minerals in beta-thalassemia minor

Homozygous beta-thalassemia is a severe hereditary disorder associated with osteopenia. Recently it was suggested that thalassemia minor may be a risk factor for osteoporosis. The purpose of the present study was to investigate this suggestion. Bone mineral status was assessed in 22 premenopausal women and 21 men with beta-thalassemia minor. In vivo neutron activation analysis was applied to measure hand-bone phosphorus (HBP), single-photon absorptiometry to measure forearm bone mineral content (BMC), and dual-energy X-ray absorptiometry to measure spinal bone mineral density (BMD). Comparison of the HBP, BMC, and BMD values with those of sex- and age-matched healthy subjects without the beta-thalassemia trait failed to indicate a statistically significant difference for either sex group. Concerning the biochemical markers of bone metabolism that were studied (serum calcium, phosphate, alkaline phosphatase, osteocalcin, and parathyroid hormone, and 3-h fasting urine calcium-to-urine creatinine ratio) no difference was observed between the study subjects and matched controls. In conclusion, the present study showed that subjects with beta-thalassemia minor are not at risk for osteoporosis.

Evaluation of six tumor markers in patients with carcinoma of unknown primary

We have retrospectively evaluated six serum tumor markers in 85 patients with carcinoma of unknown primary. The serum levels of carcinoembryonic antigen (CEA), CA 19-9, CA 15-3, CA 125, beta-chorionic gonadotropin (beta-HCG) and alpha-fetoprotein (AFP) were related with the histological pattern (undifferentiated carcinoma or adenocarcinoma), the number and the site of metastases, as well as the response to chemotherapy and the patients' survival. More than 40% of the patients had increased serum levels of all six tumor markers, except of AFP which was found to be increased in only 17% of them. Increased levels of CA 19-9 were related to metastatic adenocarcinoma, whereas CA 19-9 and CA 15-3 had a relationship with more advanced disease. Patients with liver involvement had higher mean levels of CEA and CA 19-9 as compared to those with nodal disease. None of these markers was found to have a predictive value for response to chemotherapy or survival. Although the present study has a retrospective nature, it allows us to conclude that patients with CUP have a nonspecific over-expression of the above serum tumor markers and that routine use of these markers does not offer any diagnostic or prognostic assistance.

New evidence that tamoxifen does not induce osteoporosis: a nuclear activation analysis and absorptiometry study

The possibility of increased risk for osteoporosis in breast cancer patients treated with tamoxifen was investigated. 26 patients aged 41-65 years without skeletal metastases were studied. All patients were treated with 20 mg/d tamoxifen for a mean time of 22 months. The data obtained by in vivo neutron activation analysis of the phosphorus content in hands, were supplemented with data obtained by single photon absorptiometry in the forearm and radiographic morphometry. Comparison of the data with that of age and sex matched normal controls showed that breast cancer patients treated with tamoxifen are not prone to osteoporosis.

Limitations of quantitative CT in corticosteroid induced osteopenia

Single energy spectrum quantitative CT (SES-QCT) was applied for the assessment of the trabecular bone mineral status in patients under long-term corticosteroid treatment. Seventeen renal graft recipients (RGR) and 12 patients receiving corticosteroid treatment for collagen disease were studied. A reduction of about 40% in the spinal trabecular bone density relative to matched controls was found, associated with the corticosteroid administration. Repeated measurements showed significant reduction in density 4 months after transplantation, and an increase in density after graft rejection. Radiologic or clinical evidence of osteopenia in the spine was not found. Other noninvasive techniques, applied in the upper extremities of the RGR, showed only minor bone reduction compared to controls. The findings of the present study suggest that adipose tissue deposition in the spinal trabeculae can introduce errors in the measurements. Therefore, SES-QCT should not be applied during corticosteroid therapy.

Comparison of measured parameters from a 24-keV and a broad spectrum epithermal neutron beam for neutron capture therapy: an identification of consequential parameters

Epithermal neutron beams are under development in a number of locations in the U.S. and abroad. The increased penetration in tissue provided by these neurons should circumvent problems associated with the rapid attenuation of thermal neutron beams encountered in previous clinical trials of neutron capture therapy (NCT). Physical and radiobiological experiments with two "intermediate energy" or "epithermal" beams have been reported. A comparison is made here between the 24-keV iron-filtered beam at Harwell, England, and the broad-spectrum Al2 O3 moderated beam at the Brookhaven Medical Research Reactor (BMRR). In addition, parameters which are relevant for NCT, and which are best suited for evaluation and comparison of beams, are discussed. Particular attention is paid to the mean neutron energy which can be tolerated without significant reduction of therapeutic gain (TG), where TG is the ratio of tumor dose to maximum normal tissue dose. It is suggested that the simplest and most meaningful parameters for comparison of beam intensity and purity are the epithermal neutron fluence rate, and the fast neutron dose per epithermal neutron (4.2 X 10(-11) rad/neutron for the broad-spectrum beam and 29 X 10(-11) rad/neutron for the 24-keV beam). While the Al2O3 beam is close to optimal, the 24-keV beam produces a significant fast neutron dose which results in a lower TG.(ABSTRACT TRUNCATED AT 250 WORDS)

In vitro determination of uptake, retention, distribution, biological efficacy, and toxicity of boronated compounds for neutron capture therapy: a comparison of porphyrins with sulfhydryl boron hydrides

A major problem remaining in the evaluation of boronated compounds for neutron capture therapy (NCT) is the need to know the intra- or extracellular microdistribution of boron. This is a consequence of the short range of the 10B(n,alpha)7Li reaction products (approximately 10 microns), such that biological efficacy is dependent upon intracellular distribution. In particular, if boron location is predominantly extracellular, a significant reduction in efficacy would be expected. The in vitro procedure described here was developed mainly to provide information regarding the intra- and extracellular location and concentration of boron. However, use of the technique also allows the measurement of compound uptake and retention (binding) and the determination of biological efficacy by the evaluation of survival curves obtained following irradiation with thermal neutrons. Comparison is made to results obtained with boric acid (H3(10)BO3) and to results calculated for various boron distributions. Concomitantly, an indication of compound toxicity can be obtained from the plating efficiency of unirradiated control cells. Currently, most investigators utilize in vivo systems for testing and evaluating boron uptake from various carrier molecules. Given the large number of boron compounds being synthesized and needing evaluation as to their usefulness for NCT, the in vitro technique described here is simple and advantageous for initial compound screening. In addition to sparing animal lives, it is both time and cost effective and utilizes much smaller quantities of test compound than are required for an in vivo assay. A boronated porphyrin (BOPP) evaluated by the above procedure shows an uptake and retention approximately 20 times that of sulfhydryl boron hydride monomer (BSH); the latter compound is currently being used clinically for NCT in Japan and is anticipated for use in clinical trials in the United States. If the advantages demonstrated by BOPP in these in vitro studies are validated in animal experiments, BOPP should be considered for clinical application.

Installation and testing of an optimized epithermal neutron beam at the Brookhaven Medical Research Reactor (BMRR)

NCT is a binary system, in which 10B is physiologically targeted to tumor and then allowed to interact with thermal neutrons generated in the treatment volume by an externally applied neutron beam. Consequently, an unusually large number of parameters are obtained, which bear on the resultant Therapeutic Gain (TG). However, a perusal of these data, as illustrated in Figure 7, indicates that the TG would increase significantly beyond values projected in this paper if the absolute amount of 10B could be increased above 30 ppm. For example, increasing 10B concentration in tumor to 45 ppm would increase TG by approximately 33% (with a T/N of 5). A similar increase in TG would follow an increase in T/N from 5 to 10. Those associated with the development of boron compounds for NCT feel that such developments are within reach.

Samarium-145: a new brachytherapy source

A new radiation source has been produced for brachytherapy, with radiation energies slightly above those of 125I, and a T1/2 of 340 d. This source, 145Sm, is produced by neutron irradiation of 144Sm (96.5% enriched). Decay is by electron capture with 140 K x-rays per 100 disintegrations in the energy region between 38-45 keV, plus 13 gamma-rays at 61 keV. These sources are encapsulated in Ti tubes, approximately 0.8 mm X 4.5 mm, and have been developed for temporary implantation in brain and ocular tumours. The 38-61 keV photons should make such sources easy to shield, while providing a dose distribution from source arrays somewhat more homogeneous than that from 125I. In addition, the 340 d half life of 145Sm permits its use for times significantly longer than that of 60 d 125I. While the 145Sm sources have been designed primarily for implantation in a brain tumour, they should be useful for almost any conventional brachytherapy application.