The latest development in technology for cameras for sale can be truly astounding.  But it can also leave patients wondering why the same advancements aren’t being made in medical imaging.  To help give you a better idea of the new developments in medicine, we have decided to focus on the Extremity CT Scanner.  The device is promising, and below are five things everyone should know about it.

Casey Roberts is a student and also writes for the online magazine Radiology Assistant,  which helps students find the right radiology degree.

Due to developing technologies, the medical field is constantly changing and evolving. As a result, the branch of plastic surgery is advancing at an ever-changing pace. Therefore, it is imperative for medical professionals involved in the specialty of plastic surgery to upgrade their instruments on an ongoing basis to ensure they are best serving their patient population. Plastic surgeons’ decisions are based on years of medical research and they are very familiar with complex procedures when deciding which operations and which surgical instruments to use to perform complicated surgeries.

Whether for medically indicated plastic surgery or elected plastic surgery for aesthetic enhancement, this branch of medicine is wide and varied and there is a large array of precision plastic surgery instruments used. The most common surgical instrument used in plastic surgery is the scalpel, an extremely sharp knife which is used to cut tissue in many procedures. The scalpel comes in many sizes and shapes and there are even new models that pulse very quickly: 50,000x per second; cutting and sealing at the same time.

Another surgical instrument commonly used by plastic surgeons is the skin expander, used to stretch pieces of skin to make them larger, as needed. Also, often used for a number of procedures are forceps, which come in a number of types including: forceps for delicate dressing and tissue, hemostatic, micro, suturing and tissue-grasping forceps.

Surgical scissors also play an important part in the world of plastic surgery, and some of the types of surgical scissors include: delicate dissecting, gum, ligature and stitch and micro. There are also standard needle holders and micro needle holders available.

A representative list of additional surgical instruments used in plastic surgery includes: areola markers, auricular plastic instruments, breast dissectors, breast elevators, breast retractors, cartilage and bone instruments, chisels, gouges, coriotome, elevators, lip and cheek retractors, lip and cleft palate instruments, mallets marking and measuring instruments, maxilla mobilizer, mouth gags, mucosa knife and raspatories, nasal dressing forceps, nasal files and rasps, nasal forceps, nasal retractors, nasal saws, nasal septum forceps, nasal specula, osteotomes, raspatories, rhinoplasty knives, rhinoplasty scissors, septum straightening forceps, suction raspatories, swiss therapy wires and wire instruments.

Also popular are silicone implants used for reconstructive or augmentative plastic surgery and dermatomes; which are surgical instruments used to produce thin slices of skin from a donor area, in order to use them for making skin grafts. One of the dermatome’s main applications is for reconstituting skin areas damaged by burns or trauma.

Surgical lasers are often used, as they make extremely exact, focused incisions with minimal blood loss and the cuts are very precise with minimum tissue damage.

Maintaining all surgical instruments used in plastic surgeries is essential, so it is important to stay on top of all tool repair and reconditioning for top performance.

What is Surgical Diathermy?
Surgical diathermy, also known as electrosurgery, is the passage of a high-frequency alternating current through the body to produce a desirable surgical effect. Despite extensive use, many surgeons and anesthetists remain ignorant of its governing principles and associated hazards. Diathermy involves the deliberate use of electrical energy to produce tissue damage and despite the incorporation of various safety measures, injury to patients still occurs.

Principal Electrosurgical Tissue Effects
The main electrosurgical tissue effects are:
• Electrosurgical cutting divides tissue with electric sparks that focus intense heat at the surgical site. By sparking to tissue, the surgeon produces maximum current concentration. To create this spark, the surgeon should hold the electrode slightly away from the tissue. This will produce the greatest amount of heat over a very short period of time, resulting in vaporization of tissue.
• Electrosurgical fulguration (sparking with the coagulation waveform) coagulates and chars the tissue over a wide area. Since the duty cycle (on time) is only about 6 percent, less heat is produced. The result is the creation of a coagulum rather than cellular vaporization. In order to overcome the high impedance of air, the coagulation waveform has significantly higher voltage than the cutting current. Use of high-voltage coagulation current has implications during minimally invasive surgery.
• Electrosurgical desiccation occurs when the electrode is in direct contact with the tissue. Desiccation is achieved most efficiently with the “cutting” current. By touching the tissue with the electrode, the current concentration is reduced. Less heat is generated and no cutting action occurs. The cells dry out and form a coagulum rather than vaporize and explode.
• Many surgeons routinely “cut” with the coagulation current. You can also coagulate with the cutting current by holding the electrode in direct contact with tissue. It may be necessary to adjust power settings and electrode size to achieve the desired surgical effect. The benefit of coagulating with the cutting current is that you will be using far less voltage. Similarly, cutting with the cut current will also accomplish the task using less voltage. This is an important consideration during minimally invasive procedures.

The Electrosurgery Equipment Market
The electrosurgery device market is lucrative and highly competitive. Several surgical diathermy device manufacturers exist, and many creative techniques are used to differentiate products. Some device manufacturers make claims in marketing campaigns that are hard to merge with the laws of physics or basic physiology. The variety of claims may be confusing to surgeons who are investigating the purchase of new electrosurgical products. Understanding a few basic principles of electrosurgery physics can allow a surgeon to be a more informed consumer of electrosurgical products.

Surgical diathermy is an invaluable aid in modern surgery, and most contemporary diathermy machines are considered safe. The literature has proven to be quite meager in terms of reference to complications, although prolonged courses of treatment are required in a number of individual cases.

Injuries and Complications of Surgical Diathermy
The ever-increasing use of high-frequency surgery is a fundamental part of modern-day surgery. Risks and complications are still on the increase, despite the incorporation of various safety measures. The origins of surgical diathermy date back to the discoveries of D’Aversonal in 1893 and Nagelschimidt in 1909, who investigated the effects of the controlled use of high-frequency currents on biological tissue.

As the technique became more widespread, there was a rise in the number of injuries and complications reported and especially, of burns directly associated with diathermy. These were generated by the increasing use, in the interest of patient safety, of other electrical devices, coupled with ignorance of current flow interactions brought about by the associated use of a variety of medical devices. The potential explosion of combustible gases in anesthesia, endogenous intestinal gas, the induction of arrhythmias and the effect on pacemakers as the result of alternating current frequency, create extra risks in electrosurgery.

Additionally, muscle fibers can be activated by the direct electrical stimulation of diathermy and also by blocked motor endplates. This can lead to contraction of the major muscles, which may in turn be misinterpreted as insufficient anesthesia.

The role of diathermy in surgical practice has expanded significantly in recent years. As a result, the patient, surgeon and operation room staff are frequently exposed to hazards such as: burns injury, electrocution, hypoxic stress, inhalation of diathermy plume (also known as diathermy smoke), and gene mutation. However, strict adherence to preventive measures such as proper connection and handling of the diathermy machine, avoidance of inflammable operation room gases, the use of suction device, operation room scavenging system and diathermy plume extraction system significantly reduces the hazards.

Alternative Pain Relief in the Mainstream
In the last few decades, many medical professionals have found that there are several ways to help their patients heal without the use of or with limited use of long-term pain medication use. Therapies such as therapeutic massage, neuromuscular stimulators, and therapeutic ultrasound have revolutionized the way the medical community can aid in patient healing.

Another type of technology that has shown real worth in the clinical setting is shortwave diathermy. This method of controlling pain and increasing the blood flow to damaged muscle areas acts with deep heat, as opposed to sound waves like therapeutic ultrasound. In conjunction with other non medication-based therapies, shortwave diathermy can help a large number of patients with varying degrees of injury, as well as different types of injury.

How Shortwave Diathermy Works
The temperature distribution in the tissues heated by short radio waves results from the pattern of relative heating, which is the amount of energy converted to heat at any given location. The practitioner should choose a heating modality that produces the highest temperature at the site of focus, without exceeding the temperature tolerance at the affected site or in tissues above or below that site. The temperature rise depends on the properties of the tissue, including the specific heat, thermal conductivity, and the length of time that the heating modality is applied.

The temperature rise and distribution of heat that are associated with RF (Radio Frequency), are superimposed on the physiologic temperature distribution in the tissues, prior to diathermy application. Usually, the superficial temperature is low at the skin surface and higher at the core.

The Physiological Effects of Temperature
The physiological effects of temperature occur at the site of application and in distant tissue. The local effects are caused by the elevated temperature response of cellular function by direct and reflex action. Locally, there is a rise in blood flow with associated capillary dilatation and increased capillary permeability. Initial tissue metabolism increases, and there may be changes in the pain threshold. Distant changes from the heated target location include reflex vasodilatation and a reduction in muscle spasm (as a result of muscle relaxation).

Vigorous heating produces the highest temperature at the site where the therapeutic result is desired. The tissue undergoes a rapid temperature rise, with the temperature coming close to the tolerance level. Vigorous heating is used for chronic conditions that require deep structures, such as larger joints, to be heated. When acute inflammatory processes are occurring, deep heating requires extreme care, because it can obscure inflammation.

Local tissue temperature is maintained during mild heating, the primary effect being the production of a higher temperature at a site distant from the heating modality’s application. Reflex vasodilatation occurs when the rise in temperature is slow for short periods, such as during a sub-acute process. With the proper application, superficial and deep heating methods can accomplish mild heating.

Radiofrequency (RF) Energy and Shortwave Bands
When radio-frequency energy of sufficient intensity is directed at biological tissue, it will cause heating. This effect was recognized many years ago and has been used therapeutically since 1928. Commercial units generate RF energy at shortwave bands (13 MHz, 27 MHz, etc.)

Shortwave diathermy (SWD) equipment is designed to emit either a constant or a pulsed output and sometimes provides both. Constant output units are used primarily to achieve deep heating of tissues. Pulsed output allows cooling between pulses, heats less strongly and possibly enhances the non-thermal influences of RF energy. Many studies have shown a beneficial therapeutic effect with pulsed output, although the mode of action remains still obscure.

Continuous Shortwave Diathermy
Continuous Shortwave Diathermy (SWD) is widely used clinically, but remains poorly researched. Practical details of Continuous Shortwave Diathermy (SWD) use are not included here. However, it should always be kept in mind that this equipment can cause serious burns if used incorrectly.

The design of shortwave diathermy units will vary between the manufacturers, as does the maximum power output and range of compatible applicators.

Each unit consists of a generator and amplifier designed to deliver an output at a single frequency and with intensity capable of producing therapeutic effects. The energy at the output of the amplifier is fed to a coupling circuit that delivers the energy via various types of applicators, to the patient. The whole system is tuned into resonance manually or automatically to allow the maximum amount of energy to be delivered.

The applicators convey energy either by acting as a capacitor, in which the tissues of the patient behave as a dielectric within the electric field, by means of rigid or flexible air- or felt-spaced electrodes, or by acting as an inductor. The latter technique employs an insulated cable that is either pre-formed into a flat spiral and contained within an insulated casing, or is wound by hand to enclose or lie adjacent to the target tissue which then behaves primarily as a conductor within a magnetic field. The ability of these applicators to heat the musculature, while retaining a low temperature in the subcutaneous fat varies considerably.

The very simplified explanation of the RF heating effect can be as following: Oscillating electric and magnetic fields produce heat in biological tissues by inducing a rapidly alternating movement of ions, rotation of dipolar molecules and the distortion of non-polar molecules. A movement of ions represents a real flow of current and occurs readily in tissues rich in electrolytes, such as blood vessels and muscle. Resistance to this flow leads to heart production.

By contrast, in fatty tissue the main effect of an alternating electromagnetic field is to produce rotation and distortion of molecules, which does not constitute a real flow of current, therefore little heat is generated.

The activity of the Continuous Shortwave Diathermy (SWD) field at molecular level should cause blood vessels and muscle to heat strongly and adipose tissue to heat properly. Experience reveals, however, that adipose tissue is also heated vigorously because it is permeated by small blood vessels that contain a solution of electrolytes. The heat generated is then retained due to the insulating properties of fat allowing a high temperature to develop. Fibrous tissue is not particularly rich in either blood vessels or fat and usually shows a moderate elevation of temperature.

How Therapeutic Changes Occur
Therapeutic changes only occur when the temperature of the tissue rises to 40-45oC. Below this there is little demonstrable effect. At higher temperatures the rate at which proteins denature proceeds more rapidly than repair, resulting in irreparable cell damage and acute pain.

In general, the tissue response to Continuous Shortwave Diathermy (SWD) compares closely with that from other methods of heating, and the common indications and contradictions are similar to those for superficial heating. Those differences which do however exist, originate in the patterns of heating generated by the diathermies, which are unlike those produced by more superficial heating. Diathermy heats both the deep and superficial layers of tissue whilst the effect of superficial heating is most marked in the skin and subcutaneous tissues. The physiological response also depends upon the magnitude of the rise in temperature, rate of rise, volume of tissue heated and the efficiency of the homeostatic mechanisms active in dissipating heat.

For far too long, the effective design and manufacture of a reliable and affordable digital X-ray radiographic imaging system has been in process, but not completely achieved. Finally, at the end of the last century, commercially available flat panel digital X-ray detectors using amorphous silicon found their permanent place in the X-ray imaging world.
In the current digital era, we are collecting, storing, analyzing and using more and more information at a faster and faster pace. X-ray imaging is no exception. The forces behind the digital X-ray revolution are much the same as those powering home and office technologies. Digital devices are smaller and more robust and once an image is digital, it becomes portable. The x-ray image can easily be made available in multiple locations at the same time, as it can be transmitted over long distances in real-time. Digital images make it possible to have computer-assisted diagnoses. Digital images are far simpler to archive and much less costly than their analog counterpart, film. Digital images, video sequences and even volumetric data sets are easily linked to a patient’s electronic record. Just as digital technologies have dramatically improved home audio and video fidelity, digital X-ray technology offers significant improvement in image quality and dose utilization.

Medical modalities, such as CT, PET, SPECT, MRI and ultrasound are naturally digital. However, standard X-ray radiography and fluoroscopy are still mainly based on analog technologies; specifically, screen/film and the image intensifier. Flat panel detectors (FPDs) have emerged as the next generation digital X-ray technology. Flat panel X-ray imagers are based on solid-state integrated circuit (IC) technology, similar in many ways to the imaging chips used in visible wavelength digital photography and video.

A number of detector technologies have been developed based on amorphous silicon TFT (Thin Film Transistor) arrays, but the most successful and widely used detectors are called “indirect” detectors. These detectors are based on amorphous-silicon TFT/photodiode arrays coupled with X-ray scintillators.

With indirect digital X-ray imaging, an X-ray tube sends a beam of X-ray photons through a target. X-ray photons not absorbed by the target strike, a layer of scintillating material that converts them into visible light photons. These photons then strike an array of photodiodes which converts them into electrons that can activate the pixels in a layer of amorphous silicon. The activated pixels generate electronic data that a computer can convert into a high-quality image of the target, which is then displayed on a computer monitor.

The most common scintillators are the same ones used in the conventional screens in radiography and fluoroscopy. The success of this indirect X-ray photons conversion to electric signals stems from the fact that both scintillator and amorphous silicon technologies were previously developed for other applications.

The less -sed screens are based on the “indirect” approach. With the indirect approach, the flat panel detector consists of a sheet of glass with a thin layer of silicon that is in an amorphous, or disordered state. On a microscopic scale, the silicon has been imprinted with millions of transistors arranged in a highly ordered array.
Each of these TFTs is attached to a photon-absorbing diode, making up an individual pixel. Photons striking the diode are converted into two carriers of electrical charge, called electron-hole pairs. An electron-hole pair consists of a negatively charged electron and a positively charged hole (a vacant energy space that acts as if it were a positively charged electron).

Since the number of charge carriers produced will vary with the intensity of incoming light photons, an electrical pattern is created that can be swiftly read and interpreted by a computer to produce a digital image. Since the sensitivity of such an array is not good enough, a scintillator is added in front of the diode (which are “photodiodes”) to enhance the electric signal output.
The performance of the imagers is rated as the value of DQE. DQE is defined as the “Detective Quantum Efficiency“. Quantum efficiency (QE) of a detector is intended as the average fraction of the input quanta which is used in the formation of the output signal, no matter if the single input quantum generates a distinct output signal or not.
The DQE is generally defined by the ratio of the squared output signal-to-noise ratio of the imaging detector.

Radio Frequency Interference (RFI) and Medical Equipment

With the assimilation of wireless communication technology into hospital infrastructures, hospitals are becoming concerned about the impact of radio frequency (RF) electromagnetic interference (EMI) between wireless technologies and medical equipment. Such interference may cause undesirable changes to medical equipment, possibly resulting in misdiagnosis, mistreatment, and/or patient injuryThese wireless communication devices include: wireless Local Area Networks (LAN), Bluetooth, wireless telecommunications, paging, two-way radios, telemetry devices, cell phones, wireless Personal Digital Assistants (PDA), and PC tablets/laptops. While most medical devices are manufactured now with a recommended 3V/m (10V/m for life support devices) immunity level against interference from RF emissions (IEC 60601-1-2), older equipment may have inadequate shielding and, therefore, be more susceptible to interference.

Preventing Interference

Wireless devices are becoming mainstream in today’s society. The pervasiveness of the mentioned wireless devices in the medical field is unavoidable and here to stay, with more being introduced all the time. So, what is the most logical solution for hospitals? One option is to do nothing and deal with the RFI interference if and as it happens. Another option is to test every electronic-based medical device in the hospital to gauge and measure the potential of interference issues. Unfortunately, it is virtually impossible to test every combination of transmitting wireless device and electronic-based medical device.

There have been many discussions, meetings, publications, and suggestions regarding the use of portable communications equipment in the vicinity of medical equipment over the past 20 or so years. Most of these dealt with the early problems reported in infusion pumps, electric wheelchairs, pacemakers, and anesthesia machines; which due to inadequate shielding, temporarily failed while exposed to EMI.

Also, early on in the life of cellular phones, analog systems operated with quite extensive RF outputs. There were reports of interference with electric wheelchair circuits, cardiac pacemakers, and anesthesia equipment. Of course, telemetry equipment was particularly vulnerable. It was then that the fear of cellular phones in hospital began. Consequently, many hospitals totally or partially banned cell phone use in the building.

The Hazards of Electromagnetic Interference

Electromagnetic interference with electronic circuits can be dangerous in many ways. As a result, for many years, military, aircraft, and automotive electronics systems have been required to meet strict RFI requirements for immunity to up to 200 V/m, because these systems could encounter such levels during normal operations. The technology has already been developed to “harden” most medical devices against fields that are much more intense than the 3 V/m level specified in present RFI standards for medical devices. Most hardening techniques are not costly if they are incorporated into the initial design of the electronics system. Standard RF immunization techniques include the use of shielding, grounding and filtering. Shielding includes enclosing the device in metal boxes or in plastic boxes coated with metallic paint.

Grounding of electronics circuitry and cable shields is an inexpensive but necessary step toward ensuring RFI immunity. RF filtering of signal-carrying conductors, especially in sensitive patient monitoring equipment, should be performed carefully. The potential for the success of these techniques has been demonstrated in implanted cardiac pacemakers, which commonly achieve immunity of up to 200 V/m, even though these devices monitor weak electrophysiological voltages.

RF Filters and Shielding

The use of RF filters preceding the input circuitry of an implanted medical device is uncomplicated and basic. However, patient-connected medical devices, which are powered by an AC line, must accommodate the safety requirements for electrical leakage currents, as well as RFI immunity requirements. Therefore, patient connection leads on devices that obtain power from AC lines must utilize special techniques to simultaneously meet both types of safety requirements. Techniques for isolating patients, which incorporate optical or transformer coupling, may be required. In addition, designers can add interference recognition and fail-safe circuitry to their medical devices. For example, many cardiac pacemakers are protected from erratic operation by being programmed to revert to a fixed rate when RFI is detected.

Mobile RF and wireless communications systems can be optimized for compatibility with medical electronics. The modulation frequencies of RF transmitters should be outside the physiological passband of most or all medical devices. Digital modulation schemes that use time division multiple access (TDMI) and the associated amplitude modulation pulses, should be carefully designed to avoid RFI. Frequency modulation, or non-pulsed, spread spectrum modulation techniques, such as certain forms of code division multiple access (CDMA) can be used.

Managers of facilities where sensitive medical devices are used should control RFI by careful planning and system design. For example, the radiated power of many modern handheld and portable cellular phones is under the control of the base station. When close to a base station, handheld and portable phones may operate at power levels far lower than the maximum power of 600 miliWatt (for handheld phones) or 3 Watt (for portable phones). Thus, when a base station is located near a health care facility or when low power base stations (microcells) are used within the facility, cellular phones will normally operate at low power. However, the base station itself must be properly sited to avoid causing RFI. If deemed necessary, RF sources can be restricted from the more sensitive areas of a hospital, such as intensive care units.

Administrators of healthcare facilities can impose restrictions on the use of mobile RF transceivers. The concept of a specific minimum separation distance for each type of mobile transceiver has recently been proposed. For example, handheld cellular phones that radiate 600 mW would have to be kept at least one meter from a medical device that is immune to 3 V/m. A 3 Watt handheld transceiver would have to be kept 2.4 meters from the same device. In practice, an additional safety factor should be required to account for enhancement of signals by field reflections.

FDA Recommendations on Dealing with RFI Issues

FDA recommendations which were published in 1994 can still be considered as the proper guidelines on how to deal with RFI problems:

• Be aware that EMI can cause steady, momentary, or intermittent disruption of the performance of medical devices.
• Follow the recommendations of the device manufacturer for avoiding EMI.
• Purchase equipment that conforms to EMC standards.
• Consider preventing known sources of interference (e.g. cellular phones, hand-held transceivers) from coming too close to patient monitors and other sensitive electronic medical devices.
• When an EMI problem is suspected, contact the device manufacturer for assistance. Local clinical engineers may also be able to assist in identifying and correcting the problem.
• Report device problems to FDA’s MedWatch Program and note if the problem is believed to be linked to interference from a recognizable source of EM energy in the vicinity.

The Advantages of Brachytherapy
Brachytherapy is radiation therapy of cancer. The treatment is performed by placing radioactive sources in or near the tumor. In this way, the tumor is treated from inside the body so it receives the highest possible radiation dose with minimal exposure to the surrounding tissues. Teleradiotherapy, which is achieved by the aid of medical high-energy particles accelerators, is an alternative approach to radiotherapy treatment.

Remote afterloading brachytherapy means that the source is accurately positioned at the tumor by a special mechanical-electronic system through thin tubes or needles. After the treatment, the source is withdrawn into the shielded source-container, which is the major part of the brachytherapy system. Brachytherapy can be performed with short treatment times, high dose rate brachytherapy, or over a longer period of time, low dose or pulsed dose rate brachytherapy. 

Remote Afterloading Brachytherapy for Precision  

 Remote afterloading improves radiation control and provides technical advantages, such as isodose distribution optimization, that improve patient care. Replacing manual afterloading with remote afterloading reduces the radiation exposure to radiation oncologists, physicists, attending physicians, source curators, nurses, and other allied health personnel.

Remote afterloading is an application of the As Low As Reasonably Achievable (ALARA) principle in radiation control. Remote afterloading offers less probability of temporarily misplacing radioactive sources or actually losing sources, events that do occur with manual afterloading.

High dose rate remote afterloading devices yield dose rates greater than 0.2-Gy/min; doses of several gray generally are delivered in minutes. High dose rate remote afterloading is particularly appealing to facilities with large patient populations. If treated by conventional manual brachytherapy instead, prolonged hospitalizations would be indicated. Treating these patients as outpatients, using multiple fraction treatment regimens on a remote high dose rate device, is appealing to the patients. Freestanding radiation therapy centers that do not provide hospital rooms, find high dose rate units appealing, as well. A dedicated treatment suite with an overhead x-ray tube and fluoroscopy can accommodate many patients yearly, as large workloads are possible on a single unit. There is little radiation exposure to attending medical personnel and none to adjacent patients.

Applicators can be rigidly secured for the short treatment times common with high dose rate therapy. Consequently, undesired applicator movement observed during prolonged hospital stays required with brachytherapy is reduced. In some instances, the high dose rate remote afterloading sources can be configured more advantageously, yielding more desirable dose distributions than those achieved with conventional radioactive sources and manual afterloading. And last but not the least, the very small diameter of high activity source in high dose rate remote afterloading system allow treatments of interstitial and intraluminal sites previously untreated or treated only with difficulty with the conventional techniques.

The Features of Remote Afterload Brachytherapy Systems

All remote afterload systems offer four essential features:
• A primary storage safe to contain the sources when not in use.
• A mechanism to move the source from the storage safe to and from the applicator in the patient.
• A system to maintain the source in the applicator for a set time in desired positions and to determine their position.
• A mechanism to return the source to the storage safe at the end of treatment and during power failures or other emergencies.

Remote Afterloading Systems Offer Flexibility 
Remote afterloading of radioactive sources for brachytherapy is becoming increasingly popular as evidenced by the increased sales of remote afterloading systems. With low, medium, and high dose rate options, these units offer the potential for superior dose distributions and the practical advantages of better radiation protection. However, as with any new technology, these systems generate a host of new concerns that the users must address. Remote afterloading systems present a unique set of radiation control questions, particularly when the units fail to function adequately and the sources stick in the applicators. Also, there are no explicit protocols for source calibration. Often, calibration of these sources yields activities at odds with those provided by the manufacturers. This need for a dosimetry protocol is particularly important for the high-activity 192Ir sources which are exchanged frequently.
Often existing hospital rooms or teletherapy vaults not originally designed for the remote afterloading systems are used to house these units. Certain disadvantages in such uses should be considered.