Handheld Metal Detector Research Articles

The utility of handheld metal detector in confirming metallic foreign body ingestion in the pediatric emergency department

We aimed to identify the presence of ingested metallic foreign bodies with handheld metal detector in the pediatric population. All children (n=40) known or suspected to have ingested a MFB and who presented to the Emergency Department of the Children's Hospital of Ege University were prospectively ascertained. All patients underwent both radiographic evaluation and handheld metal detector scanning of the chest and abdomen on their presentation. In the present prospective study, we compared handheld metal detector scanning with plain radiography. The end point of the study compared metallic foreign body findings with handheld metal detector vs radiological findings during an eight-month period. Forty subjects with possible metallic foreign body ingestion were enrolled into the study. The principle investigator scanned all subjects. Disease was defined by the presence of a foreign body in the gastrointestinal tract on radiograph. Radiographically, 35 foreign bodies were found, and handheld metal detector revealed 31 of them. The sensitivity of handheld metal detector was 88.6% (95% confidence interval [CI]: 72.1%-96.5%), specificity 100% (95% CI: 61.8%-100%), positive predictive value (PPV) 100% (95% CI: 85.8%-100%), and negative predictive value 55.5% (95% CI: 34.3%-84.6%). Handheld metal detector revealed that 2 metallic foreign bodies (1 pushpin, 1 coin) were localized to the chest, which was confirmed by radiography, and urgent removal was performed with endoscopy. Handheld metal detector scanning is an accurate, inexpensive, radiation-free screening tool and should be used for evaluation of patients suspected of ingesting metallic foreign bodies.

Electromagnetic Compatibility Testing of Implantable Neurostimulators Exposed to Metal Detectors

This paper presents results of electromagnetic compatibility (EMC) testing of three implantable neurostimulators exposed to the magnetic fields emitted from several walk-through and hand-held metal detectors. The motivation behind this testing comes from numerous adverse event reports involving active implantable medical devices (AIMDs) and security systems that have been received by the Food and Drug Administration (FDA). EMC testing was performed using three neurostimulators exposed to the emissions from 12 walk-through metal detectors (WTMDs) and 32 hand-held metal detectors (HHMDs). Emission measurements were performed on all HHMDs and WTMDs and summary data is presented. Results from the EMC testing indicate possible electromagnetic interference (EMI) between one of the neurostimulators and one WTMD and indicate that EMI between the three neurostimulators and HHMDs is unlikely. The results suggest that worst case situations for EMC testing are hard to predict and testing all major medical device modes and setting parameters are necessary to understand and characterize the EMC of AIMDs.

Metallic foreign body in esophagus: Are multiple radiographs necessary?

Multiple X-rays required for confirmation and localization of ingested metallic foreign body preoperatively predisposes children to increased radiation exposure. This study aims to highlight the current necessity or otherwise of these X-ray requests. This is a retrospective study of patients with ingested metallic foreign bodies over a five-year period in a tertiary health institution. Case notes and X-ray requests were studied. Of 39 cases of foreign body in esophagus, 29 (74.4%) were metallic and the coin accounted for 79.3% of all metallic foreign bodies. There were 20 males to 9 females and 28 children aged 2 months to 11 years to one adult. There were 62 pre-extraction X-rays consisting of 29 (46.8%) initial confirmatory films and 33 (53.2%) repeat films for localization of the foreign body. There were 10 post-extraction films for postoperative complications. More than half of the X-ray films were unnecessary and the radiation exposure was avoidable if alternative methods of localization of the foreign body such as the handheld metal detector were available.

Position sensing system for eddy-current mine imager

Distinguishing of mines from scrap metal is a difficult task that provides challenge when seeking an ultimate solution. An eddy-current imaging feature added to standard handheld metal detector is an option for such discrimination. Our metal detector was enhanced by an inertial measurement unit aided by velocity information, measured by optic flow sensor. It lead to further improvement of the proposed procedure by means of position and orientation tracking. The achieved accuracy of mine signal localization is 1 cm in 1×1 m scanning area.

A Metal Detector Study to Locate Inactive Small Arms Range Impact Areas

Historical records suggested the existence of .45 caliber Thompson sub-machine gun ranges near the Fort Lewis Evergreen Range; however, the precise location of the bullet impact area was not known. The site covered 20 acres, too large to cost-effectively characterize using convention grid sampling techniques. As an alternative, a study was conducted using a hand-held metal detector to locate the bullet impact areas. The metal detector chosen, a Garrett Graphic Target Imaging™ (GTI) 2500, has an LCD screen, which provides the user information on the potential size and depth of the object causing the signal. A two-man team performed the study and bullet detection was confirmed by excavation. The metal detector proved effective at finding .45 caliber bullets. Three impact areas were successfully identified and marked using a global positioning system (GPS). The metal detecting strategy saved substantial sampling time and over $35,000.00 by decreasing the sampling area by 93 percent.

Things that go beep: experience with an ED guideline for use of a handheld metal detector in the management of ingested non-hazardous metallic foreign bodies

Objectives: To review compliance with our emergency department (ED) guideline on the imaging of ingested non-hazardous metallic foreign bodies in children, investigate adverse outcomes, and make suggestions for improving the...

Inductive and capacitive array imaging of buried objects

Despite ongoing research and development efforts, landmine and unexploded ordnance infestation continues to be a problem. Remediation efforts typically utilise inexpensive hand-held metal detectors that rely on the principle of electromagnetic induction. While these devices often detect all relevant metal objects, they generally cannot discriminate between harmful objects and harmless clutter. False indications continue to far outnumber verified detections. One promising method for improving the discrimination between harmful and harmless objects is the use of sensor arrays that provide images of hidden objects and complementary information about the buried object from a variety of angles. This paper will review the progress of high-resolution inductive and capacitive sensing array development for buried object detection. These sensor arrays use unique designs incorporating a single drive with multiple sense elements. The drive creates a shaped magnetic or electric field pattern that concentrates the field energy into longer wavelength spatial modes with 'focused' penetration into the ground. Images obtained from scans over buried objects provide a basis for spatial filtering and signal processing while multiple sensor arrays placed at different positions within the drive provide different 'views' of buried objects and clutter. Model-based grid measurement methods will also be reviewed as a real-time method for multiple property measurements, and real-time data analysis/image generation.

Evaluation and management of the cardiovascular patient embarking on air travel

This case-centered review summarizes the risks of air travel and available studies and recommendations for air travel among patients with cardiovascular disease. General Considerations: Although overall risk is small, cardiac events are the second most common cause (after vagal events) of in-flight medical incidents. Several mechanisms could predispose travelers to myocardial ischemia and arrhythmia during air travel, including cabin pressurization to less than that at sea level (median cabin altitude on modern aircraft was found to be 2259 m in one study), and mental stress associated with flying. In theory, increased sympathetic tone and decreased oxygen tension found at altitude could lead to myocardial ischemia, or atrial or ventricular arrhythmias. Although the occurrence of ectopy has been correlated with altitude among healthy volunteers, altitude has not yet been associated with sustained ventricular tachycardia among patients at risk. Specific Recommendations: The American Medical Association, American College of Cardiology, and Aerospace Medical Association advise abstention from flying for 2 to 3 weeks after uncomplicated myocardial infarction (or the same duration after stabilization following complicated myocardial infarction). Although preflight stress testing has not been specifically addressed, reliance on history and physical examination appears to be appropriate for preflight screening. There are no data that suggest air travel interferes with pacemaker or internal cardiac defibrillator (ICD) function. However, these devices (but not intracoronary stents) will trigger preflight security metal detectors. Because the alternating magnetic field associated with hand-held metal detectors could trigger ICD discharge, patients should request a “hand search” if possible. Supplemental oxygen is not routinely required for patients with cardiovascular disease. However, patients requiring supplemental oxygen at sea level will require supplemental oxygen during air travel. Finally, owing to venous stasis and hemoconcentration associated with dehydration, there is an increased risk of deep vein thrombosis and pulmonary embolus associated with air travel of long duration. One small study found fewer thrombotic complications among patients receiving low molecular weight heparin as a single dose 2 to 3 h before air travel. This should be considered for patients at high risk who are not chronically anticoagulated. DB

The use of a hand-held metal detector for localisation of ingested metallic foreign bodies - a critical investigation.

Ingested metallic foreign bodies (MFBs) are usually diagnosed by taking X-ray films of the neck, chest and/or abdomen. This study evaluates the use of a hand-held metal detector (HHMD) for the diagnosis and localisation of MFBs. In a prospective study, 53 consecutive paediatric patients with history of a swallowed MFB were examined with X-rays and HHMD. In 47 children, the MFB could be verified radiologically. Coins were most frequently swallowed. The HHMD could detect and locate all coins but only 47% of other MFBs. There were no false-positive results. A HHMD is an effective tool for screening the location of suspected ingested coins. This method is easy, inexpensive and free of radiation. Very small MFBs cannot be reliably detected. If an innocuous metallic foreign body is clearly identified with a hand-held metal detector in the stomach or lower gastrointestinal tract of an asymptomatic child, additional radiological confirmation is not required.

Calculation of induced current densities and specific absorption rates (SAR) for pregnant women exposed to hand-held metal detectors

The finite difference time domain (FDTD) method in combination with a well established frequency scaling method was used to calculate the internal fields and current densities induced in a simple model of a pregnant woman and her foetus, when exposed to hand-held metal detectors. The pregnant woman and foetus were modelled using a simple semi-heterogeneous model in 10 mm resolution, consisting of three different types of tissue. The model is based on the scanned shape of a pregnant woman in the 34th gestational week. Nine different representative models of hand-held metal detectors operating in the frequency range from 8 kHz to 2 MHz were evaluated. The metal detectors were placed directly on the abdomen of the computational model with a spacing of 1 cm. Both the induced current density and the specific absorption rate (SAR) are well below the recommended limits for exposure of the general public published in the ICNIRP Guidelines and the IEEE C95.1 Standard. The highest current density is 8.3 mA m−2 and the highest SAR is 26.5 µW kg−1. Compared to the limits for the induced current density recommended in the ICNIRP Guidelines, a minimum safety factor of 3 exists. Compared to the IEEE C95.1 Standard, a safety factor of 60 000 for the specific absorption rate was found. Based on the very low specific absorption rate and an induced current density below the recommended exposure limits, significant temperature rise or nerve stimulation in the pregnant woman or in the foetus can be excluded.

Handheld metal detector confirmation of radiopaque foreign bodies in the esophagus.

To examine the utility of handheld metal detectors in confirming the position of radiopaque foreign bodies in the esophagus before delayed endoscopic removal. Prospective study of patients evaluated between June 1, 1997, and August 31, 1999. Tertiary pediatric referral center. Twenty-six of 139 children presenting consecutively for evaluation of esophageal foreign bodies met eligibility criteria and completed the study protocol. Inclusion in the study was contingent on a delay of at least 6 hours from the time of diagnosis to the time of endoscopic removal. All patients underwent both radiographic evaluation and handheld metal detector scanning of the chest and abdomen on presentation and immediately before endoscopic removal. All patients evaluated during the study period had coins lodged within the esophagus. Handheld metal detector scanning accurately confirmed this position before endoscopic removal in all cases. Our data suggest that handheld metal detectors may obviate the need for repeated radiographs in patients whose foreign bodies cannot be removed at presentation.

Metal Detectors for Metallic Foreign Body Localization

Use of handheld metal detectors (HHMDs) to identify and localize ingested metallic foreign bodies has recently received much attention. Two new studies

Safer Security Pages

Back to table of contents Previous article Next article LetterFull AccessSafer Security PagesMelissa Eshelman, M.D., and Michael Resnick, M.D.Melissa EshelmanSearch for more papers by this author, M.D., and Michael ResnickSearch for more papers by this author, M.D.Published Online:1 Mar 1999https://doi.org/10.1176/ps.50.3.418aAboutSectionsView EPUB ToolsAdd to favoritesDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InEmail To the Editor: Safety in psychiatric emergency departments is of paramount importance. Two studies reported that between 4 and 8 percent of patients searched in a psychiatric emergency setting had a weapon (1,2). Security measures used in emergency departments include on-site security, routine use of hand-held metal detectors, closed-circuit surveillance, secure rooms, panic buttons, and a paging code (3).Our medical center conducted a review of safety policies and procedures after a former patient entered the lobby of our emergency psychiatric facility with a loaded firearm. The patient unfortunately committed suicide, but no one else was physically injured.During the review, attention focused on procedures for notifying staff of a dangerous situation. Our facility uses a security code—Code Green—in a verbal public-address page to alert mental health and security personnel of a potentially violent situation and to direct the staff to respond to that location. The code is the same whether or not a weapon is involved. A telephone survey we conducted of 12 hospitals in the Pacific Northwest found that only four have a designated code for a behavioral emergency involving a weapon.The use of a security paging code in a situation where a patient has a loaded firearm could be potentially disastrous if it summoned more potential victims to that location. We are in the process of adopting a separate paging code that would not only make staff aware of the dangerous circumstances but also warn them to avoid the area, keep others away, and allow security officers and police to respond.Given the need to anticipate potential acts of violence, we hope other mental health facilities will consider using a similar system.Dr. Eshelman and Dr. Resnick are associated with the Crisis Triage Center of the Providence Portland Medical Center in Portland, Oregon.

Metal detectors and swallowed metal

Hand-held metal detectors can quickly and accurately locate most metallic objects children tend to swallow, according to a study in the August 1994 Pediatric Emergency Care. Twenty-three children seen in an emergency room for swallowing metallic foreign bodies were searched with handheld metal detectors. The detectors correctly identified 15 of 16 X-ray-confirmed swallowed metallic objects, including coins, button batteries, medallions, tokens, needles and marbles, and correctly eliminated six X-ray-negative cases. The only unidentified case was an ingested needle.

Hand-held metal detector identification of ingested foreign bodies

The study purpose was to determine the ability of hand-held metal detectors (HHMDs) to identify the presence of ingested metallic foreign bodies (MFBs). Twenty-three children presenting to the emergency department with a complaint of MFBs ingested were enrolled. Sixteen of 23 patients had radiographically proven foreign bodies. The MFBs comprised coins (n = 11), a button battery (n = 1), a medallion (n = 1), a token (n = 1), a needle (n = 1), and a marble (leaded glass) (n = 1). The HHMD correctly detected 15 of 16 radiographically positive MFBs (93%) and correctly excluded a potential MFB in six of six radiographically negative cases. The only foreign body not detected was an ingested needle. One radiograph was equivocal. Radiographic localization of the ingested objects was as follows: esophagus, n = 4; stomach, n = 9; and intestines, n = 3. The HHMD correctly localized all detected MFBs. The HHMD had a sensitivity of 94%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 86%. HHMDs are effective screening devices for possible ingested MFBs. Positive studies localized to the stomach and lower gastrointestinal tract do not require confirmatory radiographic studies.

Metal detectors to detect aluminium

EDITOR,—D M Bradburn and colleagues highlight the poor radiodensity of aluminium.1 We now use a hand held portable metal detector (Adams Electronics, Edenbridge, Kent) to detect the presence of metal fragments in patients presenting to our accident and emergency department with …

Airport metal detectors and orthopedic implants. The responses of arch and hand-held devices.

8 subjects with a variety of orthopedic implants were examined by the security staff at an international airport using arch and hand-held metal detectors. None of the subjects caused activation of the alarm on the arch, although the presence of metal was registered in 2 at a level below the alarm threshold. The hand-held detectors alarmed over the larger superficial implants. A substantial tissue screening effect was noted.

USE OF A METAL DETECTOR FOR LOCALISATION DURING FIBRESIGMOIDOSCOPY OR LIMITED COLONOSCOPY

An inexpensive hand-held metal detector has proved effective during colonoscopy in locating the fibre-endoscope tip at the splenic flexure or demonstrating the presence of a loop in the sigmoid colon. Endoscopic localisation without fluoroscopy may be inaccurate, and the metal detector, quick and easy to use, should be a useful adjunct to limited colonoscopy or fibresigmoidoscopy.