- Email: [email protected]
The role of radiology in podiatry
RAD
APHERS
Radiography(
The role of radiology R. L. Ashford,
C. J. Fullerton*
Fncdty of He& md Convmrt~ify Cm-, University of Centm/ Etlglmd Birrninghnm B42 2SU; Tentre for Podiatric Ehcnfion, Be/fast Cify Hosyihd, Queen’s University of Belfast, Beljosf BT9 7AB, Nor//tern Ire/ml U.K. (Received 9 Mny 7 996; nccepted 2 Mnrch 1998)
Key word:
1998)4,189-194
in podiatry and N. J. Hughes
The purpose of this paper is to give allied professionals and its application in the practice of podiatry.
a brief overview
of radiology
podiatry.
Introduction What is chiropody/podiatry? The standard definition as listed by The Society of Chiropodists and Podiatrists, is [I] Chiropody may be defined as the maintenance of the feet in healthy condition, and the treatment of their disabilities by recognized chiropodial/podiatric methods in which the practitioner has been properly trained. The above definition is very broad and gives no indication as to the level or scope of practice of the modem day practitioner. Before developing the definition further it is probably appropriate to clarify the terms chiropody and podiatry. In the U.K., both terms are being used interchangeably, but in the wider European and indeed international arena the term podiatrist is being more favoured as one who treats foot-related problems including surgical procedures. There are very good reasons why the term chiropody has lingered in this country but for the purpose of the paper the term podiatry will be used. The history of the podiatry profession has been dealt with elsewhere [2-51 and makes interesting reading, particularly when compared to other professions supplementary to medicine. One of the 1078-8174/98/030189+08518.00/0
most significant events in the profession’s history, certainly in terms of legislation, was the Professions Supplementary to Medicine Act of 1960. This Act provided for the establishment of the Chiropodists Board (among other Boards for other professions), whose remit was to monitor standards of training and examinations, to register those members of the profession who have passed courses and examinations deemed by it to be of a sufficiently high standard, and to publish an annual register [6]. Podiatric education, like other professions supplementary to medicine, has undergone a dramatic shift in the last decade. Within this period, the profession has become an-all-graduate profession. The origins, Philosophies and the move toward a graduate profession makes interesting reading and can be traced to other documents [7, 81 and interestingly, parallels between the development of radiography and podiatry can be seen. Undergraduate degrees are now offered at all 15 recognized schools of podiatry. The vast majority of the schools are l&ted within Universities or Colleges of Higher Education. It is probably not surprising that each school has its own idiosyncrasies in relation to their own curriculum. However, there is a commonality in terms of core subjects and a requirement by the Registration Board for newly qualified students to be competent practitioners [9]. This implies that the 0 1998 The College of Radiographers
Ashford et al.
190
final educational outcome in terms of scope of practice, should be similar. The development of undergraduate education ran alongside the extension of the scope of practice promulgated by a group of professionals interested in the development of foot surgery. Interestingly, the practice of foot surgery had been well established by podiatrists in the United States. The development of post-registration education in foot surgery emanated initially from one of the professional bodies, namely the Podiatry Association after 1975. The model they adopted led to the formation of advanced courses in pharmacology, pathology and anatomy. In addition, radiology became mandatory for the surgical podiatrist who now must satisfy the requirements of the Ionizing Radiations Regulations, 1988 [9]. In essence, the two developments-degree education and surgical practice-have facilitated an expansion in the podiatrist’s scope of practice. The modem day practitioner must have a wide range of relevant medical knowledge to give them a sufficient depth of understanding to manage and take total responsibility for the health of the foot and lower limb. They must, by necessity, be a reflective practitioner who can use their knowledge base to prescribe the best possible treatment regimes for their patients.
History
of radiology
and podiatry
Prior to the 197Os, X-rays were used as a diagnostic modality on an intermittent basis. They were utilized by the few chiropodists who held hospital appointments or private chiropodists who had access to X-ray facilities. The initiation of surgical practice within the private sector demanded that practitioners have access to diagnostic X-rays. Initially, private practitioners modified the heads of simple dental X-ray machines to allow simple radiographs to be taken. As podiatric surgery developed within the NHS, radiographs were requested from NHS X-ray departments. Podiatrists also utilized computerized tomography, bone scans and magnetic resonance imaging to aid diagnosis.
Usage-diagnosis The main use of X-rays in podiatric
practice are:
Figure 1. Normal foot. Bisection of talus passes through shaft of first metatarsal. Cyma line intact curve. Normal angle of inclination of calcaneus, 18”20”. Sinus tarsi visible.
0 confirmation of diagnosis, e.g. exostoses, accessory bones, osteochondritis and fractures; l investigation prior to surgery, example, hallux valgus; l arthropathy-to determine the severity of the disease process; l bone tumours l charting of radiographs to quantify an osseous deformity. The last use suggested above may need a little expanding in relation to podiatry. Podiatric charting enables the podiatrist to enhance the written descriptive analysis and conclusion of the radiographic examination. Using reference points, lines, and angles, relationships of osseous structures are compared. This information is used to analyse pathology, positional relationships and to classify foot types. Foot types include rearfoot varus, equinus foot type, forefoot valgus and forefoot supinatus. These foot types all function in a slightly different manner, and in doing so, altered angular and articular relationships can be detected on X-ray. As an example of this, with compensated rearfoot varus, an important articular relationship such as the cyma line (mid-tarsal joint articulation) displays a lazy-s line. If the rearfoot varus deformity compensates on weight bearing, then a break in the articular line is observed. This is one observation from a radiograph which aids the process of diagnosis. Figures 1-4 illustrate an example of the change in the cyma line when one compares a normal foot X-ray to a foot which is in a pronated position (rearfoo t varus). Information derived from charting is only reliable if the methods used are consistent and repeatable. Such methods can contribute to the diagnosis of osseous deformities, such as tarsal coalition. The talocalcaneal angles measured on an anteroposterior and lateral projection are increased with
Role of radiology
Figure 2. Normal foot. Smooth uninterrupted mid-tarsal joint cyma line. Talar deviation 15”. Talonavicular joint 75% congruent.
Fig-me 3. Pronated foot. Bisection of talus Passes below shaft of first metatarsal. Anterior break in cyma line. Decreased angle of inclination of calcaneus. Sinus tarsi obstructed.
t
191
in podiatry
15”
Figure 4. Protonated line. Tarsal deviation congruent.
foot. Broken mid-tarsal joint cyma t 15”. Talonavicular joint 1 75%
talocalcaneal coalition [lo]. With talipes equinovarus (club foot) the talocalcaneal angle is reduced whilst the talo/lst metatarsal angle is increased compared with normal values. This aids in the quantification of the underlying deformity [II]. Radiographic charting is also used to quantify the improvement in osseous alignment post hallux valgus surgery [12].
Undergraduate
education
At the undergraduate level, radiology as a discipline receives different emphasis in each of the 15 institutions. This can vary from a core subject in some of the degrees to an elective subject in year three. The syllabuses presented in
this paper are from two schools of podiatry and as a result it should be clear that there are degrees of commonality and diversity within each. The School of Podiatry in the University of Central England (IKE) introduces the students very quickly to the principles of radiology. During their first year, podiatry and radiography students receive a module on the principles of physiological control. At this level, one of the objectives is for each of the two groups to be able to recognize anatomical features on radiographic images. Within one of the core level 1 modules for podiatry students, taught by a radiographer and amounting to approximately 4 hours, a brief synopsis of health and safety issues, the correct referral criteria and assessing radiographs for technical quality are all delivered. During their second year (level 2), students receive a variety of radiological information, primarily from a podiatrist and a radiographer. The focus in this year is towards the radiographic projections and the views used in podiatry and conditions which require referral. In year three, students are introduced to radiological charting, interpretative radiology and they are offered an elective subject dealing with advanced clinical practice. This elective module, as one would expect, goes beyond the basic core subject areas previously outlined. The Centre for Podiatric Medicine in The Queen’s University of Belfast introduces students in second year (level 2) to a brief overview of the use of X-rays in podiatry practice. This includes a J-hour session on basic radiographic anatomy, common projections used and the reasons for utilizing radiographic investigation. In the final year, a Jo-hour course concentrates on radiation hazards, interpretation and workshop sessions. An elective is offered to students in the final semester’ which involv& radiographic charting and the use of advanced imaging techniques appropriate to podiatry practice.
Post-graduate
education
Radiology plays a key role .in ‘post-graduate education, especially in the pos t-diplomate surgical qualification programme. This includes lmowledge of changes in osseous structures, such as density and structural variation, periosteal activity, articular change, fractures and healing of bone, infections, neoplasia, specific effects of disease on bone, with emphasis on metabolic change, vascular,
Ashford
192
neurotrophic changes and soft tissue densities and opacities. Attendance at a course which satisfies the Ionising Radiation and Protection of Persons Act 1988 is required prior to registration for the post-graduate examination. This course is included in the general radiology component ,of the postdiplomate surgical qualification programme [9]. The radiology component is delivered by radiologists who hold the Fellowship of the Royal College of Radiologists (FRCR). As well as having the ability to prescribe, and to make diagnoses from plain radiographs, knowledge of pertinent techniques in the imaging of the foot and leg are required. This includes imaging techtomography, ultraniques such as computerized resonance imaging [ 131. sound and magnetic Although plain radiography is used as a basic investigation for the diagnosis of tarsal coalition, it is computerized tomography which is regularly used to confirm the exact location of the osseous coalition [lo]. Enhanced diagnostic accuracy of soft tissue injuries and osteomyelitis is achieved with magnetic resonance imaging (MRI). Tendo achilles rupture or partial ruptures are accurately diagnosed using these techniques 1141. Reports also demonstrate a high degree of sensitivity and specificity of osteomyelitis by MRI in for the identification patients with foot infections 1151. Liaison between the Podiatrist and General Practitioner can result in the patient being referred for these more advanced imaging techniques.
Figure Central
5. X-ray England.
Table
I. Example
School
Kilovoltage
Dorsiplantar Lateral foot
foot
Dorsiplantar
hallux
Lateral
of Podiatry,
of exposure
Area
hallux
FFD = focal
Equipment
unit,
film
factors
University
et al.
of
used Exposure
time
FFD
60
0.4 s
SO cm
70
0.4 s
80 cm
50 60
0.6 s 0.4 s
80 cm SO cm
distance.
used
The equipment used in podiatry is very similar to the small dental units on the market. There are a few specialized companies who produce units specifically for podiatric use both in terms of size and limitation of output. Figure 5 illustrates the unit in use at UCE. This unit has the following specifications: 3 step-kV range 50, 60, 70 kVp, 10 mA, 0.55 kW, 240 v AC 50 Hz; inherent filtration of 2 mmA1, light beam diaphragm collimation; 1.2 mm’ focal spot size. The X-ray tube head of the unit is mounted on a forked gimbal, and allows rotation of 360 degrees around the vertical and 270 degrees around the horizontal. Angulation scales are fitted to allow accurate repeat projections to be carried out. The timer is electronic calibrated in 0.05 s intervals up
to 0.3 s, then to 3 s. Pre-heat delay time is 0.25 s. The kilovoltage control is stepped to provide high (70 kV), medium (60 kV) and low (50 kV) settings. A 4 m exposure cable is linked to the hand switch (plh Medical Ltd, Watford). The unit is located within a light-tight, ventilated room which doubles as a processing area. Radiation protection measures include a full length mobile screen (1.5 mmPbE), local rules (including details of direction of X-ray beam, hazard warning lights and notices etc.) and standard lead rubber aprons for patients. Exposures are made onto Agfa Curix RP1 film/screen system. Examples of exposure factors utilized are reproduced in Table 1. Control measures and local rules were produced before the unit was put into operation. The local rules took into account features of the room
Role
of radiology
Figure
6.
in podiatry
An orthoposer.
193
This box-like
structure is used by podiatrists
including the location of the X-ray equipment. Quality control measures include regular processor monitoring, standard testing of the X-ray unit for X-ray leakage, exposure time, kilovoltage and the (240 v) mA produced. The unit is designed to run from a standard domestic power supply, and its location has been designed to ensure that the ring main to which it is connected does not include other high-powered equipment (to avoid overload). Special alignment boxes (orthoposer boxes) have been constructed to allow repeatability of views used in podiatry. Figure 6 illustrates one such device in the Centre at Queen’s University. Standardized radiographic projections are performed in such a way as to conform to a Without standardization, recognized standard. radiographic images would be diagnostically unreliable. It is important that these procedures be repeated identically, with either the same patient or a succession of different patients to produce directly comparable images. Some differences emerge in the standardization of views between podiatrist and radiographer. This is particularly important if serial measurements are to be produced. As the podiatrist is primarily concerned with foot function, most views in podiatry are taken weight bearing, i.e. in the erect
as an aid to the standardization
of foot X-rays.
position. This is to reflect the effect of body weight upon the osseous structures and to quantify the angular changes of osseous alignment within the foot. Other differences include taking views of individual feet rather than both feet together. If both feet were viewed on the same exposure, divergence of X-rays would give a mildly distorted view. Finally, views should be taken in ‘the angle and base of gait position’. The angle of gait is the angle that the feet make with each other during gait. The base of gait is the distance between the media1 malleoli during locomotion.-An attempt is made to duplicate this ‘angle and base of gait when taking the dorsoplantar and lateral views. These alterations in the technique aim to reflect the functional position of osseous structures during weight bearing. To aid the standardization process an orthoposer box (Fig. 6) is utilized by podiatrists. The lines on the orthoposer box make it possible to have the central ray from the light beam diaphragm parallel to the lines on the box with the radiation striking the X-ray cassette at right-angles. This provides a greater degree of uniformity and repeatability when taking a series of lateral or axial views. The typical exposures used by podiatrists for foot X-rays are as indicated in Table 2.
Ashford et a/.
194
TabIe 2. Exposures used by podiatrists Distance kVP mA Exposure time
Restrictions on use of radiographs podiatry (legal requirements)
80 cm 65 10
0.15 s
in
necessitates a better communication between professional groups in the future. The stage is now set for professionals allied to medicine to come together on a number of different fronts and to pursue areas of mutual interest. Within UCE, the school of podiatry and radiography are actively pursuing a number of projects that will be beneficial to both professions.
References In 1988, the Ionising Radiations and Protection of Persons Act 1988 came into force. This demanded that all practitioners involved in taking or directing/requesting others to take X-rays must adhere to the requirements of the legislation. It also dictated that equipment must be regularly checked by engineering staff, that professional staff should be appropriately trained, and it issued guidelines to staff for safe usage of X-rays and the wearing of dosemeters in designated areas.
1. Berry BL, Black ]A. What is chiropody/podiatry?
2. Lorimer D. A short history of the Society of Chiropodists
4.
5. 6.
As most radiography is undertaken in NHS X-ray departments, radiographs are returned to the podiatrist with the radiologist’s report. If this arrangement does not apply, podiatrists are advised to have radiographs interpreted by a radiologist if they are unsure about the diagnosis.
7.
The main purpose of this paper has been to give fellow professionals an overview of the use of radiology in podiatry. During the planning and writing of the paper, it became evident that closer working relationships between the two professional groups is a necessity, especially in the light of communal teaching in higher education and the centralization of these professional groups within institutions. It was also very clear that the move towards multidisciplinary health care teams
1945-1995. ] Br Podiatr Med 1995; 5: 5-28. C. The origins of the Society of Chiropodists and Podiatrists and its history 1945-1995 Part (I). ] BI Podiatr Med 19%; 9: 135-41. Dagnall C. The origins of the Society of Chiropodists and Podiatrists and its history 1945-1995 Part (II). ] Br Podiah Med 1995; 10: 151-6. Dagnall C. The origins of the Society of Chiropodists and Podiatrists and its history 1945-1995 Part (III). ] Br Podiatr Med 1995; 11: 174-81. The Chiropodists Board and the Designated Authority for Chiropody in the United Kingdom, CPSM, 1995. The Chiropodist. Degrees in chiropody. ] Sot Chirop
3. Dagnall
Who makes the diagnosis?
Conclusion
The Foot
1992; 2: 59-60.
1986;
41:379-80.
8. CPSM.
PSM education and training. i%e nest decade, London: CPSM, 1979. 9. Ashford RL, Tollafield DR, Axe D..Podiatry education in the UK. T/re Foot 1995; 5: 1-7. 10. Salomao 0, Napoli MMM, de Carvalho AE, et al. Talocalcaneal coalition: diagnosis and surgical management. Foot 6 Ankle 1992; 13: 251-7. II. Tachdijian MO. The child’s foot. Philadelphia: WB Saunders Company, 1985: 170-6. 12. Thordarson DB, Leventen EO. Hallux valgus correction with proximal metatarsal osteotomy: two-year follow-up. Foot &Ankle 1992; 13: 321-6. 13. The Podiatry Association. The Diploma of Fellow of the Podiatry Association. Examination Regulations (revised 1991).
14. Kabbani YM, Mayer DP. Magnetic resonance imaging of tendon pathology about the foot and ankle. ] Am Podiatr Med Assoc 1993; 7: 418-20. 15. Nigro ND, Bartynski WS, Grossman SJ and Kruljac S. et al. Clinical impact of magnetic resonance imaging in foot osteomyelitis. ] Am Podiatr Med Assoc 1992; 12: 603-15.
APHERS
Radiography(
The role of radiology R. L. Ashford,
C. J. Fullerton*
Fncdty of He& md Convmrt~ify Cm-, University of Centm/ Etlglmd Birrninghnm B42 2SU; Tentre for Podiatric Ehcnfion, Be/fast Cify Hosyihd, Queen’s University of Belfast, Beljosf BT9 7AB, Nor//tern Ire/ml U.K. (Received 9 Mny 7 996; nccepted 2 Mnrch 1998)
Key word:
1998)4,189-194
in podiatry and N. J. Hughes
The purpose of this paper is to give allied professionals and its application in the practice of podiatry.
a brief overview
of radiology
podiatry.
Introduction What is chiropody/podiatry? The standard definition as listed by The Society of Chiropodists and Podiatrists, is [I] Chiropody may be defined as the maintenance of the feet in healthy condition, and the treatment of their disabilities by recognized chiropodial/podiatric methods in which the practitioner has been properly trained. The above definition is very broad and gives no indication as to the level or scope of practice of the modem day practitioner. Before developing the definition further it is probably appropriate to clarify the terms chiropody and podiatry. In the U.K., both terms are being used interchangeably, but in the wider European and indeed international arena the term podiatrist is being more favoured as one who treats foot-related problems including surgical procedures. There are very good reasons why the term chiropody has lingered in this country but for the purpose of the paper the term podiatry will be used. The history of the podiatry profession has been dealt with elsewhere [2-51 and makes interesting reading, particularly when compared to other professions supplementary to medicine. One of the 1078-8174/98/030189+08518.00/0
most significant events in the profession’s history, certainly in terms of legislation, was the Professions Supplementary to Medicine Act of 1960. This Act provided for the establishment of the Chiropodists Board (among other Boards for other professions), whose remit was to monitor standards of training and examinations, to register those members of the profession who have passed courses and examinations deemed by it to be of a sufficiently high standard, and to publish an annual register [6]. Podiatric education, like other professions supplementary to medicine, has undergone a dramatic shift in the last decade. Within this period, the profession has become an-all-graduate profession. The origins, Philosophies and the move toward a graduate profession makes interesting reading and can be traced to other documents [7, 81 and interestingly, parallels between the development of radiography and podiatry can be seen. Undergraduate degrees are now offered at all 15 recognized schools of podiatry. The vast majority of the schools are l&ted within Universities or Colleges of Higher Education. It is probably not surprising that each school has its own idiosyncrasies in relation to their own curriculum. However, there is a commonality in terms of core subjects and a requirement by the Registration Board for newly qualified students to be competent practitioners [9]. This implies that the 0 1998 The College of Radiographers
Ashford et al.
190
final educational outcome in terms of scope of practice, should be similar. The development of undergraduate education ran alongside the extension of the scope of practice promulgated by a group of professionals interested in the development of foot surgery. Interestingly, the practice of foot surgery had been well established by podiatrists in the United States. The development of post-registration education in foot surgery emanated initially from one of the professional bodies, namely the Podiatry Association after 1975. The model they adopted led to the formation of advanced courses in pharmacology, pathology and anatomy. In addition, radiology became mandatory for the surgical podiatrist who now must satisfy the requirements of the Ionizing Radiations Regulations, 1988 [9]. In essence, the two developments-degree education and surgical practice-have facilitated an expansion in the podiatrist’s scope of practice. The modem day practitioner must have a wide range of relevant medical knowledge to give them a sufficient depth of understanding to manage and take total responsibility for the health of the foot and lower limb. They must, by necessity, be a reflective practitioner who can use their knowledge base to prescribe the best possible treatment regimes for their patients.
History
of radiology
and podiatry
Prior to the 197Os, X-rays were used as a diagnostic modality on an intermittent basis. They were utilized by the few chiropodists who held hospital appointments or private chiropodists who had access to X-ray facilities. The initiation of surgical practice within the private sector demanded that practitioners have access to diagnostic X-rays. Initially, private practitioners modified the heads of simple dental X-ray machines to allow simple radiographs to be taken. As podiatric surgery developed within the NHS, radiographs were requested from NHS X-ray departments. Podiatrists also utilized computerized tomography, bone scans and magnetic resonance imaging to aid diagnosis.
Usage-diagnosis The main use of X-rays in podiatric
practice are:
Figure 1. Normal foot. Bisection of talus passes through shaft of first metatarsal. Cyma line intact curve. Normal angle of inclination of calcaneus, 18”20”. Sinus tarsi visible.
0 confirmation of diagnosis, e.g. exostoses, accessory bones, osteochondritis and fractures; l investigation prior to surgery, example, hallux valgus; l arthropathy-to determine the severity of the disease process; l bone tumours l charting of radiographs to quantify an osseous deformity. The last use suggested above may need a little expanding in relation to podiatry. Podiatric charting enables the podiatrist to enhance the written descriptive analysis and conclusion of the radiographic examination. Using reference points, lines, and angles, relationships of osseous structures are compared. This information is used to analyse pathology, positional relationships and to classify foot types. Foot types include rearfoot varus, equinus foot type, forefoot valgus and forefoot supinatus. These foot types all function in a slightly different manner, and in doing so, altered angular and articular relationships can be detected on X-ray. As an example of this, with compensated rearfoot varus, an important articular relationship such as the cyma line (mid-tarsal joint articulation) displays a lazy-s line. If the rearfoot varus deformity compensates on weight bearing, then a break in the articular line is observed. This is one observation from a radiograph which aids the process of diagnosis. Figures 1-4 illustrate an example of the change in the cyma line when one compares a normal foot X-ray to a foot which is in a pronated position (rearfoo t varus). Information derived from charting is only reliable if the methods used are consistent and repeatable. Such methods can contribute to the diagnosis of osseous deformities, such as tarsal coalition. The talocalcaneal angles measured on an anteroposterior and lateral projection are increased with
Role of radiology
Figure 2. Normal foot. Smooth uninterrupted mid-tarsal joint cyma line. Talar deviation 15”. Talonavicular joint 75% congruent.
Fig-me 3. Pronated foot. Bisection of talus Passes below shaft of first metatarsal. Anterior break in cyma line. Decreased angle of inclination of calcaneus. Sinus tarsi obstructed.
t
191
in podiatry
15”
Figure 4. Protonated line. Tarsal deviation congruent.
foot. Broken mid-tarsal joint cyma t 15”. Talonavicular joint 1 75%
talocalcaneal coalition [lo]. With talipes equinovarus (club foot) the talocalcaneal angle is reduced whilst the talo/lst metatarsal angle is increased compared with normal values. This aids in the quantification of the underlying deformity [II]. Radiographic charting is also used to quantify the improvement in osseous alignment post hallux valgus surgery [12].
Undergraduate
education
At the undergraduate level, radiology as a discipline receives different emphasis in each of the 15 institutions. This can vary from a core subject in some of the degrees to an elective subject in year three. The syllabuses presented in
this paper are from two schools of podiatry and as a result it should be clear that there are degrees of commonality and diversity within each. The School of Podiatry in the University of Central England (IKE) introduces the students very quickly to the principles of radiology. During their first year, podiatry and radiography students receive a module on the principles of physiological control. At this level, one of the objectives is for each of the two groups to be able to recognize anatomical features on radiographic images. Within one of the core level 1 modules for podiatry students, taught by a radiographer and amounting to approximately 4 hours, a brief synopsis of health and safety issues, the correct referral criteria and assessing radiographs for technical quality are all delivered. During their second year (level 2), students receive a variety of radiological information, primarily from a podiatrist and a radiographer. The focus in this year is towards the radiographic projections and the views used in podiatry and conditions which require referral. In year three, students are introduced to radiological charting, interpretative radiology and they are offered an elective subject dealing with advanced clinical practice. This elective module, as one would expect, goes beyond the basic core subject areas previously outlined. The Centre for Podiatric Medicine in The Queen’s University of Belfast introduces students in second year (level 2) to a brief overview of the use of X-rays in podiatry practice. This includes a J-hour session on basic radiographic anatomy, common projections used and the reasons for utilizing radiographic investigation. In the final year, a Jo-hour course concentrates on radiation hazards, interpretation and workshop sessions. An elective is offered to students in the final semester’ which involv& radiographic charting and the use of advanced imaging techniques appropriate to podiatry practice.
Post-graduate
education
Radiology plays a key role .in ‘post-graduate education, especially in the pos t-diplomate surgical qualification programme. This includes lmowledge of changes in osseous structures, such as density and structural variation, periosteal activity, articular change, fractures and healing of bone, infections, neoplasia, specific effects of disease on bone, with emphasis on metabolic change, vascular,
Ashford
192
neurotrophic changes and soft tissue densities and opacities. Attendance at a course which satisfies the Ionising Radiation and Protection of Persons Act 1988 is required prior to registration for the post-graduate examination. This course is included in the general radiology component ,of the postdiplomate surgical qualification programme [9]. The radiology component is delivered by radiologists who hold the Fellowship of the Royal College of Radiologists (FRCR). As well as having the ability to prescribe, and to make diagnoses from plain radiographs, knowledge of pertinent techniques in the imaging of the foot and leg are required. This includes imaging techtomography, ultraniques such as computerized resonance imaging [ 131. sound and magnetic Although plain radiography is used as a basic investigation for the diagnosis of tarsal coalition, it is computerized tomography which is regularly used to confirm the exact location of the osseous coalition [lo]. Enhanced diagnostic accuracy of soft tissue injuries and osteomyelitis is achieved with magnetic resonance imaging (MRI). Tendo achilles rupture or partial ruptures are accurately diagnosed using these techniques 1141. Reports also demonstrate a high degree of sensitivity and specificity of osteomyelitis by MRI in for the identification patients with foot infections 1151. Liaison between the Podiatrist and General Practitioner can result in the patient being referred for these more advanced imaging techniques.
Figure Central
5. X-ray England.
Table
I. Example
School
Kilovoltage
Dorsiplantar Lateral foot
foot
Dorsiplantar
hallux
Lateral
of Podiatry,
of exposure
Area
hallux
FFD = focal
Equipment
unit,
film
factors
University
et al.
of
used Exposure
time
FFD
60
0.4 s
SO cm
70
0.4 s
80 cm
50 60
0.6 s 0.4 s
80 cm SO cm
distance.
used
The equipment used in podiatry is very similar to the small dental units on the market. There are a few specialized companies who produce units specifically for podiatric use both in terms of size and limitation of output. Figure 5 illustrates the unit in use at UCE. This unit has the following specifications: 3 step-kV range 50, 60, 70 kVp, 10 mA, 0.55 kW, 240 v AC 50 Hz; inherent filtration of 2 mmA1, light beam diaphragm collimation; 1.2 mm’ focal spot size. The X-ray tube head of the unit is mounted on a forked gimbal, and allows rotation of 360 degrees around the vertical and 270 degrees around the horizontal. Angulation scales are fitted to allow accurate repeat projections to be carried out. The timer is electronic calibrated in 0.05 s intervals up
to 0.3 s, then to 3 s. Pre-heat delay time is 0.25 s. The kilovoltage control is stepped to provide high (70 kV), medium (60 kV) and low (50 kV) settings. A 4 m exposure cable is linked to the hand switch (plh Medical Ltd, Watford). The unit is located within a light-tight, ventilated room which doubles as a processing area. Radiation protection measures include a full length mobile screen (1.5 mmPbE), local rules (including details of direction of X-ray beam, hazard warning lights and notices etc.) and standard lead rubber aprons for patients. Exposures are made onto Agfa Curix RP1 film/screen system. Examples of exposure factors utilized are reproduced in Table 1. Control measures and local rules were produced before the unit was put into operation. The local rules took into account features of the room
Role
of radiology
Figure
6.
in podiatry
An orthoposer.
193
This box-like
structure is used by podiatrists
including the location of the X-ray equipment. Quality control measures include regular processor monitoring, standard testing of the X-ray unit for X-ray leakage, exposure time, kilovoltage and the (240 v) mA produced. The unit is designed to run from a standard domestic power supply, and its location has been designed to ensure that the ring main to which it is connected does not include other high-powered equipment (to avoid overload). Special alignment boxes (orthoposer boxes) have been constructed to allow repeatability of views used in podiatry. Figure 6 illustrates one such device in the Centre at Queen’s University. Standardized radiographic projections are performed in such a way as to conform to a Without standardization, recognized standard. radiographic images would be diagnostically unreliable. It is important that these procedures be repeated identically, with either the same patient or a succession of different patients to produce directly comparable images. Some differences emerge in the standardization of views between podiatrist and radiographer. This is particularly important if serial measurements are to be produced. As the podiatrist is primarily concerned with foot function, most views in podiatry are taken weight bearing, i.e. in the erect
as an aid to the standardization
of foot X-rays.
position. This is to reflect the effect of body weight upon the osseous structures and to quantify the angular changes of osseous alignment within the foot. Other differences include taking views of individual feet rather than both feet together. If both feet were viewed on the same exposure, divergence of X-rays would give a mildly distorted view. Finally, views should be taken in ‘the angle and base of gait position’. The angle of gait is the angle that the feet make with each other during gait. The base of gait is the distance between the media1 malleoli during locomotion.-An attempt is made to duplicate this ‘angle and base of gait when taking the dorsoplantar and lateral views. These alterations in the technique aim to reflect the functional position of osseous structures during weight bearing. To aid the standardization process an orthoposer box (Fig. 6) is utilized by podiatrists. The lines on the orthoposer box make it possible to have the central ray from the light beam diaphragm parallel to the lines on the box with the radiation striking the X-ray cassette at right-angles. This provides a greater degree of uniformity and repeatability when taking a series of lateral or axial views. The typical exposures used by podiatrists for foot X-rays are as indicated in Table 2.
Ashford et a/.
194
TabIe 2. Exposures used by podiatrists Distance kVP mA Exposure time
Restrictions on use of radiographs podiatry (legal requirements)
80 cm 65 10
0.15 s
in
necessitates a better communication between professional groups in the future. The stage is now set for professionals allied to medicine to come together on a number of different fronts and to pursue areas of mutual interest. Within UCE, the school of podiatry and radiography are actively pursuing a number of projects that will be beneficial to both professions.
References In 1988, the Ionising Radiations and Protection of Persons Act 1988 came into force. This demanded that all practitioners involved in taking or directing/requesting others to take X-rays must adhere to the requirements of the legislation. It also dictated that equipment must be regularly checked by engineering staff, that professional staff should be appropriately trained, and it issued guidelines to staff for safe usage of X-rays and the wearing of dosemeters in designated areas.
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4.
5. 6.
As most radiography is undertaken in NHS X-ray departments, radiographs are returned to the podiatrist with the radiologist’s report. If this arrangement does not apply, podiatrists are advised to have radiographs interpreted by a radiologist if they are unsure about the diagnosis.
7.
The main purpose of this paper has been to give fellow professionals an overview of the use of radiology in podiatry. During the planning and writing of the paper, it became evident that closer working relationships between the two professional groups is a necessity, especially in the light of communal teaching in higher education and the centralization of these professional groups within institutions. It was also very clear that the move towards multidisciplinary health care teams
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Who makes the diagnosis?
Conclusion
The Foot
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