Q. In what way X-ray and ultra-sonography are useful for medical treatment? [44 BPSC/2002]
Ans:
X-ray is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers.
X-ray usage for medical treatment:
- Since Rontgen’s discovery that X-rays can identify bone structures, X-rays have been used for medical imaging.
- Projectional radiographs:
- It is the practice of producing two-dimensional images using x-ray radiation.
- Bones contain a high concentration of calcium, which, due to its relatively high atomic number, absorbs x-rays efficiently. This reduces the amount of X-rays reaching the detector in the shadow of the bones, making them clearly visible on the radiograph.
- It is useful in the detection of pathology of the skeletal system as well as for detecting some disease processes in soft tissue.
- The chest X-ray, can be used to identify lung diseases such as pneumonia, lung cancer, or pulmonary edema, and the abdominal x-ray, which can detect bowel obstruction, free air and free fluid.
- It is also used to detect gallstones or kidney stones.
- Evaluating how an orthopedic implant, such as a knee, hip or shoulder replacement, is situated in the body with respect to the surrounding bone.
- Dental radiography is commonly used in the diagnoses of common oral problems, such as cavities.
- Computed tomography (CT Scan):
- is a medical imaging modality where slices of specific areas of the body are obtained from a large series of two-dimensional X-ray images taken in different directions.
- These cross-sectional images can be combined into a three-dimensional image of the inside of the body and used for diagnostic and therapeutic purposes
- Fluoroscopy:
- It is an imaging technique commonly used by physicians or radiation therapists to obtain real-time moving images of the internal structures of a patient through the use of a fluoroscope. X ray projection is used in this process.
- Radiotherapy:
- The use of X-rays as a treatment is known as radiation therapy and is largely used for the management (including palliation) of cancer. It requires higher radiation doses than those received for imaging alone.
- X-rays beams are used for treating skin cancers using lower energy x-ray beams while higher energy beams are used for treating cancers within the body such as brain, lung, prostate, and breast.
Ultra-sonography is a diagnostic imaging technique, or therapeutic application of ultrasound. Ultrasound are sound waves with frequencies which are higher than those audible to humans (>20,000 Hz). Ultrasonic images are made by sending pulses of ultrasound into tissue. The ultrasound pulses echo off tissues with different reflection properties and are recorded and displayed as an image.
Ultra-sonography usage for medical treatment:
- It is widely used in It is possible to perform both diagnosis and therapeutic procedures, using ultrasound to guide interventional procedures such as biopsies or to drain collected fluid.
- Sonography is effective for imaging soft tissues of the body.
- Superficial structures such as muscle, tendon, testis, breast, thyroid and parathyroid glands, and the neonatal brain are imaged at a higher frequency (7–18 MHz), which provides better linear (axial) and horizontal (lateral) resolution.
- Deeper structures such as liver and kidney are imaged at a lower frequency 1–6 MHz with lower axial and lateral resolution as a price of deeper tissue penetration.
- Anesthesiology: In anesthesiology, ultrasound is commonly used to guide the placement of needles when placing local anaesthetic solutions near nerves.
- Angiology (vascular):
- In angiology or vascular medicine, duplex ultrasound is used to diagnose arterial and venous disease.
- In the case of the common and potentially, serious problem of blood clots in the deep veins of the leg, ultrasound plays a key diagnostic role.
- Cardiology:
- It assist in evaluation of heart valve function and strength of cardiac muscle contraction.
- Gastroenterology/Colorectal surgery:
- Abdominal and endoanal ultrasound are frequently used in gastroenterology and colorectal surgery.
- In abdominal sonography, the solid organs of the abdomen such as the pancreas, aorta, inferior vena cava, liver, gall bladder, bile ducts, kidneys, and spleen are imaged.
- Blood velocity can be measured in various blood vessels by relatively inexpensive and low risk ultrasound Doppler probes attached to portable monitors.
- Gynecologic ultrasonography examines female pelvic organs, the bladder etc.
- Obstetric ultrasound is primarily used to Date the pregnancy, Confirm fetal viability, Determine the sex of the baby etc.
- Ultrasound is the preferred imaging modality for thyroid tumors and lesions. Many other benign and malignant conditions in the head and neck can be evaluated and managed with the help of diagnostic ultrasound and ultrasound-guided procedures.
- Similarly, ultrasound is used in imaging and guiding procedures in diagnosing and treatment process for other parts of body e.g.lungs, eyes, urinary tract etc.
- Since images are captured in real-time during ultrasound, they can also show movement of the body’s internal organs as well as blood flowing through blood vessels. Unlike X-ray imaging, there is no radiation exposure associated with ultrasound imaging.
Some adverse effects:
- Ultrasonography has been considered safe imaging by the WHO.
- Although there is no evidence ultrasound could be harmful for the fetus, medical authorities typically strongly discourage the promotion, selling, or leasing of ultrasound equipment for making “keepsake fetal videos”.
- One study found a small but significant correlation between prolonged and frequent use of ultrasound and abnormal neuronal migration in mice.
- Diagnostic X-rays (primarily from CT scans due to the large dose used) increase the risk of developmental problems and cancer in those exposed.
- X-rays are classified as a carcinogen by the WHO.
- Thus it has been recognised that frequent exposure to X-rays could be harmful.
