Optical fibre based real-time measurements during an LDR prostate brachytherapy implant simulation: using a 3D printed anthropomorphic phantom.

An optical fibre sensor based on radioluminescence, using the scintillation material terbium doped gadolinium oxysulphide (Gd2O2S:Tb) is evaluated, using a 3D printed anthropomorphic phantom for applications in low dose-rate (LDR) prostate brachytherapy. The scintillation material is embedded in a 700 µm diameter cavity within a 1 mm plastic optical fibre that is fixed within a brachytherapy needle. The high spatial resolution dosimeter is used to measure the dose contribution from Iodine-125 (I-125) seeds. Initially, the effects of sterilisation on the sensors (1) repeatability, (2) response as a function of angle, and (3) response as a function of distance, are evaluated in a custom polymethyl methacrylate phantom. Results obtained in this study demonstrate that the output response of the sensor, pre- and post-sterilisation are within the acceptable measurement uncertainty ranging from a maximum standard deviation of 4.7% pre and 5.5% post respectively, indicating that the low temperature sterilisation process does not damage the sensor or reduce performance. Subsequently, an LDR brachytherapy plan reconstructed using the VariSeed treatment planning system, in an anthropomorphic 3D printed training phantom, was used to assess the suitability of the sensor for applications in LDR brachytherapy. This phantom was printed based on patient anatomy, with the volume and dimensions of the prostate designed to represent that of the patient. I-125 brachytherapy seeds, with an average activity of 0.410 mCi, were implanted into the prostate phantom under trans-rectal ultrasound guidance; following the same techniques as employed in clinical practice by an experienced radiation oncologist. This work has demonstrated that this sensor is capable of accurately identifying when radioactive I-125 sources are introduced into the prostate via a brachytherapy needle.

Prospective, randomised clinical trial of four different presurgical hand antiseptic techniques in equine surgery.

BACKGROUND: Currently, the World Health Organization recommends the use of alcohol-based hand rubs (ABR) for surgical hand preparation in human surgery. When disinfecting soaps are used, a rubbing technique causes less skin irritation than brush scrubbing. Based on a recent survey, most equine surgeons still use disinfecting soap. The efficacy of scrubbing vs. rubbing and the use of sole ABR compared with chlorhexidine (CHx)- based products has not been evaluated in the equine surgical setting. OBJECTIVES: To compare four surgical hand antisepsis techniques in equine surgery for reduction of aerobic bacterial counts from pre- to post-preparation (immediate efficacy) and at the end of surgery (sustained efficacy). STUDY DESIGN: Randomised, prospective clinical trial. METHODS: A 4% CHx-based product applied with either a scrub or rub technique, one sole ABR (ET; 80% ethanol) and one CHx/alcohol-combination (CHx/ET; 1% CHx and 61% ethanol) product both applied with a rub technique were evaluated. Samples were collected by glove juice technique and cultured on 3M™ Petrifilm plates and counted using a 3M™ Petrifilm plate reader. RESULTS: Immediate mean bacterial log10 colony forming unit (CFU) reduction was 2.4 for CHx-scrub, 2.8 for CHx-rub, 3.1 for CHx/ET and 2.1 for ET. CHx/ET resulted in significantly lower bacterial counts than CHx-scrub (P<0.005) and ET (P<0.001) while CHx-rub resulted in significantly lower counts than ET (P<0.001). At the end of surgery bacterial counts were the lowest for CHx-rub, significantly lower than CHx/ET (P<0.001) and ET (P<0.001). There was no difference between CHx-rub and -scrub techniques (P = 0.7). MAIN LIMITATIONS: Bacterial counts were used as the outcome measure rather than prevalence of surgical site infection, and the effect of hand preparation on skin health was not assessed. CONCLUSIONS: ABR did not decrease bacterial log10 CFU counts more effectively than CHx products. When using CHx soaps in the equine setting, hand-rub is as effective as a hand-scrub-technique.

Magnetic resonance imaging of lipoma and atypical lipomatous tumour/well-differentiated liposarcoma: observer performance using T1-weighted and fluid-sensitive MRI.

The aim of this study was to evaluate observer performance using T1-weighted spin-echo and fluid-sensitive MRI sequences in distinguishing between lipoma and atypical lipomatous tumour/well-differentiated liposarcoma (ALT/WDL). Magnetic resonance images of 51 patients with benign lipoma and ALT/WDL of the musculoskeletal system were reviewed. There were 33 benign lipomas and 18 ALT/WDL. The character of septa and nodularity of the fatty tumours on T1-weighted spin-echo sequences and the presence of high signal on fluid-sensitive sequences were assessed. Two independent observers took part. Observer agreement was measured. The two observers achieved sensitivities of 100 and 94% for T1-weighted images and 100% each for fluid-sensitive sequences. Specificities were 76 and 64% for T1-weighted and 70 and 73% for fluid-sensitive images. Observer agreement was very good (kappa 0.87 for T1-weighted and 0.88 for fluid-sensitive images). In distinguishing lipoma from ALT/WDL, observer performance was comparable using T1-weighted and fluid-sensitive MR sequences. High sensitivity and moderately high specificity were attained.

The "penumbra sign" on T1-weighted MRI for differentiating musculoskeletal infection from tumour.

OBJECTIVE: The "penumbra sign" on unenhanced T1-weighted MR sequences is thought to be helpful for discriminating subacute osteomyelitis from bone neoplasm. We sought to quantify the sensitivity and specificity of this sign for bone and soft tissue infection in a general referral population. DESIGN: Clinical coding was used to identify patients admitted to Middlemore Hospital (Auckland, New Zealand) between January 2000 and November 2003 with a diagnosis of either infection or neoplasm of the upper or lower limb who had undergone an MRI scan. One hundred and eighty-three patients were included in the study. Fifty-seven patients had bone or soft tissue infection. One hundred and twenty-six had a bone or soft tissue neoplasm. Relevant unenhanced T1-weighted images were selected for each patient, randomised and placed in a folder on the Hospital PACS system. Four reviewers were shown the original article describing the penumbra sign and then asked to look at the images in the folder stating whether the penumbra sign was present or absent. RESULTS: The average specificity and sensitivity of the penumbra sign for musculoskeletal infection was 96% (range 94-99%) and 27% (range 21-34%) respectively. Interobserver reliability was moderate to good with an average kappa score of 0.57 (range 0.50-0.62). For isolated soft tissue infection there was a higher sensitivity (54%, 33-83%) but with similar specificity (98%, 96-100%) and interobserver reliability (0.47, 0.33-0.58). Of the 11 out of 57 (19%) true positive penumbra signs identified by a consensus of three or more of the observers, all were subacute, chronic or acute on chronic infections. CONCLUSIONS: The penumbra sign has a high specificity for musculoskeletal infection. This is also true for isolated soft tissue infection. The penumbra sign is helpful in differentiating neoplasm from infection and its presence in the setting of a high pretest probability is useful in making a diagnosis of infection.

Total and partial ovariohysterectomy in seven mares.

REASONS FOR PERFORMING STUDY: Ovariohysterectomy appears to have a low mortality rate in mares, but the procedure needs to be reviewed because of the high risk of life-threatening complications. HYPOTHESIS: That ovariohysterectomy can be effective treatment for a variety of uterine diseases in mares and carries a good prognosis. METHODS: Diagnosis, clinical data, surgical technique, post operative care, complications and outcome were recorded from medical records of 7 mares that underwent total (6) and partial (1) ovariohysterectomy at the University of Illinois from 1994 to 2001. RESULTS: The indications for ovariohysterectomy were chronic pyometra (4 mares), chronic uterine torsion (n = 2) and chronic intramural haematoma (n = 1). Surgical exposure was difficult but was improved by traction on stay sutures and right-angled clamps. In some cases, application of the TA-90 autosuture instrument as a right-angled clamp to the caudal part of the uterus improved access to the uterine stump. The most common post operative complications were decreased faecal output, decreased intestinal sounds (4 mares) and mild abdominal pain (2). Two mares had mild to moderate incisional infections. Other previously reported complications, such as haemorrhage, septic peritonitis, uterine stump infection or necrosis, and diarrhoea, did not occur. All mares survived over follow-up periods of 6 months to 5 years and were used for riding (6 mares) and embryo transfer (1 mare, after partial ovariohysterectomy). CONCLUSIONS AND POTENTIAL RELEVANCE: According to this study, the prognosis for mares after ovariohysterectomy appears to be good, despite the technical difficulties of the procedure. The prevalence of life-threatening complications can be lower than reported.

Ultrasound of soft-tissue masses: pitfalls in interpretation.

A review of 43 patients with soft-tissue tumours identified from a tumour registry showed a 23% rate of incorrect initial diagnosis by ultrasound imaging. Seven patients, five with malignant tumours, suffered a delay in diagnosis (ranging up to 6 months) as a result. The most common error was to mistake a solid tumour for a haematoma. Caution is recommended in the interpretation of ultrasound of soft-tissue masses, particularly with regard to the erroneous diagnosis of haematoma.

Interstitial fluid and hypoechoic wall: two sonographic signs of breast abscess.

PURPOSE: Many mammographic and sonographic features of breast abscess overlap with those of carcinoma. We reviewed the usefulness of interstitial fluid and hypoechoic walls in the sonographic diagnosis of breast abscess. METHODS: The sonograms and records of 65 patients with breast infection and 60 contemporaneous patients with breast cancer were retrospectively reviewed. RESULTS: Of 49 abscesses identified in patients with breast infection, 14 (29%) had adjacent interstitial fluid that was sonographically visible, and 15 (31%) had a hypoechoic wall. No patients with breast cancer had either sign. The overall sensitivity of the presence of either sign was 55%, and the specificity was 100%. CONCLUSIONS: Two sonographic findings, interstitial fluid and a hypoechoic wall, are relatively specific for breast abscess and may aid in the diagnosis of breast disease.

Comparison of humeral head retroversion with the humeral axis/biceps groove relationship: a study in live subjects and cadavers.

The purpose of this study was to investigate whether the axis of the humeral articular surface bears a more constant relationship to the bicipital groove than to the distal humerus. This finding could help intraoperative placement of a shoulder prosthesis in the most anatomic position. Magnetic resonance imaging was used in 41 live volunteers and 9 cadavers to measure the distance from the biceps groove to a line drawn perpendicular to the midpoint of the humeral articular surface. A cadaver model with a plastic humeral prosthesis was used to convert this biceps distance into an angular measurement. The relationship between the biceps distance and the retroversion angle of the humeral head with respect to the humeral epicondyles was analyzed. The biceps distance averaged 11.8 mm+/-3.5 mm (equivalent to 26.8 degrees+/-8.3 degrees), whereas retroversion averaged 26.8 degrees +/-12.2 degrees. This difference in variability is significant (P=.008). Placing the fin of a humeral head implant 12 mm posterior to the biceps groove reproduces normal anatomy better than the use of an arbitrary standard of 30 degrees to 40 degrees of retroversion.

Implementation of image-guided large-core needle biopsy of the breast on a limited budget.

Image-guided large-core needle biopsy (LCNB) of the breast is becoming widely accepted as an accurate, minimally invasive and economical way to obtain a tissue diagnosis of breast lesions. However, much of this work has been done with expensive dedicated equipment, often favouring stereotaxic guidance. Image-guided LCNB was introduced to Middlemore Hospital based around existing inexpensive equipment, and stereotaxic or ultrasound guidance was chosen depending on which showed the lesion best. Multidisciplinary clinical, radiological and pathological assessment of each case was performed. The results of 213 biopsies (112 stereotaxic and 101 ultrasound guidance) are reported here. Malignancy was shown or suspected in 85 biopsies (40%). The absolute sensitivity for malignancy was 97% with complete sensitivity of 100%. The absolute specificity was 100% and the complete specificity 98.5%. Large-core needle biopsy can be successfully implemented in a large institution without investment in expensive equipment while maintaining high ratios of malignant/benign biopsies. Attention to technique and careful multidisciplinary review are important to the success of such a programme.

Prevertebral soft-tissue measurements in cervical spine injury.

To clarify normal values for cervical prevertebral soft-tissue measurements and evaluate when they are useful as a marker of cervical spine injury, the prevertebral soft-tissue measurements of 79 control and 57 acutely injured patients were retrospectively compared by two independent observers. The second, blinded, observer made a provisional diagnosis and indicated if increased soft-tissue measurements had assisted in making a diagnosis of injury. If measurements > 7 mm at C2/3 and > 21 mm at C6/7 were considered abnormal, a true positive rate of 53% and false positive rate of 5% were observed. The differences between the mean measurements in the control and injured groups were statistically significant (P < 0.0001 at C2/3 and P < 0.01 at C6). Soft-tissue measurement improved the diagnostic confidence of the blinded second reviewer in 17.5% of the injured group. Analysis of this subgroup revealed a 50% error rate in initial reporting. In all of these cases, the abnormal soft-tissues had been ignored prospectively Routine measurement of the prevertebral soft tissues is a simple procedure that may provide an important due to subtle cervical spine injury.

Justification for decreasing the number of views taken in radiologic follow-up of Casper plate cervical spine hardware.

RATIONALE AND OBJECTIVES: We tested the null hypothesis that there would be no difference between the diagnostic yield of the lateral radiograph alone and the yield of the lateral and anteroposterior views combined when assessing patients after placement of an anterior cervical appliance. METHODS: We evaluated 630 radiographic examinations obtained from 117 consecutive patients who had anterior cervical plating. For each examination, we looked at the lateral radiograph first and then at the anteroposterior radiography to determine whether there would be any additional information on the anteroposterior film. RESULTS: Of 501 examinations in which the lateral and anteroposterior views were available, we found that the anteroposterior view added information in 18. In eight of the 18, the added information consisted only of clinically insignificant tilting of the plate. Significant findings were seen in 209 examinations in the lateral view and in 219 examinations with the lateral and anteroposterior views combined. This was not significantly different. CONCLUSION: The anteroposterior view rarely adds significant information. It probably should be obtained early postoperatively to check for tilting of the plate but after that only for specific indications. This will save money and reduce the patient's exposure to radiation.

Tuberculosis: preventing occupational transmission to health care workers.

1. The anticipated reduction in the incidence of tuberculosis (TB) failed to consider four major factors: the advent of human immunodeficiency virus (HIV); the development of multi-drug resistant TB; the decline in public health services and limited access to health care for those in congregative facilities; and the increase in immigration of persons from countries with high prevalence of TB. 2. Some strains of multi-drug resistant TB are resistant to all anti-TB medications and seriously hamper infection control strategies. Unfortunately, MDR-TB is transmitted in the same manner as drug susceptible organisms and studies show comparable infection rates. 3. The role of the occupational health nurse in preventing workplace exposure to TB combines education, disease prevention, early detection, and treatment modalities to maximize the opportunity for a healthy work environment for health care workers.

Selective use of image-guided large-core needle biopsy of the breast: accuracy and cost-effectiveness.

OBJECTIVE: We examined the accuracy and cost-effectiveness of large-core needle breast biopsy in a selected group of patients with mammographically detected lesions. MATERIALS AND METHODS: We selectively used large-core needle biopsy to sample breast lesions that were intermediate (neither clearly benign nor clearly malignant) and wire localization biopsy to sample breast lesions that were strongly suggestive of cancer. We compared 2 years' experience using this protocol with the preceding 2 years at the University of Utah Health Sciences Center during which we did only a few large-core needle biopsies on a nonselective basis. RESULTS: Our biopsy rate increased from one biopsy per 36 mammographic screening examinations to one per 26 (p = .001) when the protocol was used. The cost of biopsy per cancer detected decreased from $11,555 to $8356. The specificity of large-core needle biopsy was 98%; the sensitivity based on limited follow-up was 100%. CONCLUSION: Large-core needle biopsy is an accurate and cost-effective method for sampling breast lesions when used in a selective fashion.

Myoepithelial lesions of the breast: imaging characteristics and diagnosis with large-core needle biopsy in two cases.

Two mammographically detected myoepithelial lesions (one each in women aged 77 and 73 years) were diagnosed at large-core needle biopsy, with the results confirmed by means of surgical excision. The imaging features were nonspecific. A key clue to the diagnosis at histologic examination was the presence of a well-defined capsule around the lesion; hence, sampling of the margins of the lesion is essential. Radiologists should be familiar with myoepithelial lesions in the differential diagnosis of fairly smoothly marginated solid masses.

Percutaneous native renal biopsy: comparison of a 1.2-mm spring-driven system with a traditional 2-mm hand-driven system.

Over the last few years spring-driven mechanical biopsy guns have been introduced for performing renal biopsies. There has been little research done comparing these guns with traditional hand-driven needles in performing biopsies of native kidneys. We wished to compare our experience with the two needle types. We studied retrospectively the results and complication rates of 155 native kidney biopsies. Sixty-nine were performed with hand-driven 14-gauge needles and eighty-six with 18-gauge, spring-driven biopsy guns. Sufficient tissue for diagnosis was obtained in 96% of cases in the hand-driven group compared with 99% in the biopsy gun group (P = NS). Complications occurred in six cases in the hand-driven group compared with one case in the biopsy gun group (P = 0.02). As expected, the reported number of glomeruli per core in the 14-gauge cores was greater than in the 18-gauge cores (16.5 v 6.2, P < 0.01). This was partially offset by the greater number of passes made with the smaller needle. We conclude that similar results can be expected from both biopsy methods, with a possible slight decrease in complications using biopsy guns with smaller needle diameters.