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In-Vivo Dosimetry

3.1 Introduction In-vivo dosimetry is used clinically to verify during treatment how accurately the planned dose is delivered to the patient. While American Association of Physicists in Medicine (AAPM) TG-62, Diode In-Vivo Dosimetry for Patients Receiving External Beam Radiation Therapy, sees in-vivo dosimetry as supplementary to a good clinical QA program, more recent developments in understanding failure modes in treatment delivery and adaptive radiotherapy have led…

Relative Dosimetry for MV Beams

2.1 Introduction Since the basic physics of dosimetry for radiation beams is extensively covered in textbooks on radiotherapy physics, this chapter will focus on the measurement of dosimetry data in clinical practice. There are two main goals in measuring relative dosimetry data: (1) confirming the accurate technical functionality of the accelerator to produce a symmetric beam of correct energy and known relative output as specified at…

Reference Dosimetry for Ionizing Radiation

1.1 Introduction The key to the accurate delivery of radiation is the ability to establish the absolute dose delivered. In radiation therapy clinical practice the primary tool used to measure absorbed dose is the ion chamber. The use of ion chambers has been well described by international codes of practice. While some of the details may differ slightly, the basic concepts of the various codes of…

Ultrasound of Muscle Injury

Introduction Muscle is probably one of the most difficult tissues in the musculoskeletal system to assess with ultrasound. There are a variety of reasons for this, including the complex anatomy of the structures involved, the isotopic nature of muscle, the different functional bundles present within muscles and compartments, and the varied site and appearance of muscle lesions. Once the examining sonographer appreciates the level of difficulty…

Ultrasound Imaging of Joint Disease

Introduction Ultrasound machines with high-resolution probes are readily available in most radiology departments and are routinely used to assess both articular and periarticular disorders. They are also becoming commonplace in rheumatology departments, reflecting the important role they now play in rheumatological disease. Ultrasound has many advantages over other imaging techniques with the ability to carry out rapid assessment of multiple joints at different locations, undertake dynamic…

Ultrasound of Soft Tissue Masses

Introduction Soft tissue masses of the musculoskeletal system are extremely common. The vast majority of lesions are benign and in many of these cases malignancy can be excluded from the history and examination without resort to imaging. Key Point Because of the overwhelmingly high ratio of benign to malignant lesions there is often a delay in diagnosing the latter and early imaging is therefore recommended when…

Specific Intervention Techniques

Shoulder Intervention Subacromial Subdeltoid Bursa Injection Patient and Probe Position Ultrasound-guided injections provide more reliable and accurate needle placement which is particularly useful to assess the diagnostic response to local anaesthethic in patients with a poor response to a previous blind injection. Guidance is also useful to ensure accurate medication placement and in difficult cases such as obese and postoperative patients. A quick wipe with a…

Musculoskeletal Intervention: General Principles

Introduction The superficial location of many musculoskeletal structures makes them readily amenable to injection therapy and many unguided injections are carried out in the office or ward setting. Large superficial structures are easily targeted, although success will vary with the practitioner's expertise. It is generally accepted that many of these unguided injections will miss their target, but, despite this, patients not infrequently report good responses. Good…

Disorders of the Ankle and Foot: Forefoot

Introduction The foot can be divided into three compartments according to the bony anatomy: the forefoot (comprising the metatarsals and phalanges, the midfoot (the cuneiforms, cuboid and navicular) and the hindfoot (calcaneus and talus). Midfoot pain and metatarsalgia are common clinical complaints. The aetiology of the symptoms is often difficult to establish clinically and imaging therefore plays an important role in the evaluation of patients. Although…

Disorders of the Ankle and Foot: Medial

Introduction Due to the superficial location of many of the structures that contribute to medial sided symptoms, ultrasound plays an important role in their assessment. Abnormalities of the medial tendons predominate, but disorders of the neurovascular structures, ligaments and even bones need to be considered. The technique for examining the medial ankle has already been discussed. Important points include the dominant role that axial images play…

Disorders of the Ankle and Foot: Lateral

Introduction The most common indications for an ultrasonographic examination of the lateral aspect of the ankle are suspicion of peroneal tendon pathology or lesions of the lateral ligament complex. Patients with ligament injuries are generally examined in a chronic phase to detect late complications of ligament tears or undiagnosed associated lesions. Ultrasonography, allowing a dynamic assessment of the structures, is the best imaging modality for examination…

Disorders of the Ankle and Foot: Anterior

Tendons Tibialis Anterior Anatomy The tibialis anterior tendon is the strongest of the anterior ankle tendons. Its parent muscle arises from the upper two-thirds of the lateral aspect of the tibia. It has a high musculotendinous junction and a strong distal tendon, which is constrained by a transverse superior and an oblique inferior retinacular band. The relationship of tibialis anterior to the retinacula is complex. The…

Disorders of the Ankle and Foot: Posterior

Introduction The most common symptoms leading to an ultrasound examination of the posterior ankle region are those associated with disorders of the Achilles tendon or the plantar aponeurosis (heel pain and/or swelling). In an acute setting, ultrasound is most often performed for suspicion of Achilles tendon tear. Other common acute and chronic indications are Achilles tendinopathy and/or paratenonitis, insertional Achilles tendon diseases, bursitis and plantar fasciitis.…

Ankle Joint and Forefoot: Anatomy and Techniques

Introduction Ultrasound examination of the ankle and foot is one of the most common examinations in musculoskeletal ultrasound. The superficial location of most structures means that ultrasound plays an important role in the management of many patients with painful conditions of the foot. As in many other joints, symptoms guide the ultrasound approach. Patients who present with pain that is located to a single area are…

Knee Pathology

Introduction Ultrasound has an important role to play in the investigation of pathology relating to the knee. However, it is important to recognize it has significant limitations, particularly with regard to the demonstration of intraarticular pathology involving structures such as the menisci, cruciate ligaments and articular cartilage. Consequently ultrasound is predominantly used for the assessment of extraarticular pathology about the knee and is particularly useful for…

Knee Joint and Calf: Anatomy and Techniques

Overview As with other larger joints, ultrasound is most useful when the patient's symptoms are localized to a relatively specific area. More diffuse symptoms suggest internal derangement due to meniscal, cruciate and cartilage injuries. These are diagnosed by MRI with relative ease and, although there have been efforts to use ultrasound to depict these structures, it is not sufficiently reliable for general diagnostic use. Until meniscal…

Disorders of the Groin and Hip: Paediatric Hip

Developmental Dysplasia of the Hip Developmental dysplasia of the hip (DDH) is a disorder where under development of the acetabulum leads to reduced femoral head coverage which, in turn, predisposes to acetabular labral abnormalities and early cartilage disease. If uncorrected, these abnormalities predispose to premature osteoarthritis, requiring hip replacement. If dysplasia is severe, the femoral head may sublux or frankly dislocate. The older name for this…

Disorders of the Groin and Hip: Lateral and Posterior

Introduction Lateral and posterior hip pain may be due to variety of intra- and extraarticular conditions. Ultrasound is a useful image modality for rapid assessment of extraarticular soft tissue abnormalities, many of which are tendon or muscle related. Certain specific soft tissue mass lesions occur around the lateral aspect of the hip, and may or may not be associated with pain. Common conditions include: greater trochanteric…

Disorders of the Groin and Hip: Anterior

Introduction The hip region is an area of complex anatomy with numerous vascular, nervous and muscular structures passing between the trunk and the lower extremity. Conditions remote to the hip joint may present as pain in the groin. Clinical examination may be nonspecific, and the choice of imaging modality may be difficult. Ultrasound is often used as a complementary technique to radiography, MRI and CT. Ultrasound-guided…

Disorders of the Groin and Hip: Groin Pain

Introduction Commoner causes of groin discomfort in the general population include inguinal hernias and muscle strains in the lower abdominal wall and upper thigh. Muscular strains in this group of patients often do not present to a primary care physician and certainly further management in the form of imaging is not necessary. The majority of symptomatic inguinal hernias can also be diagnosed clinically but there is…