Radiation therapists

Radiation therapists treat cancer in patients by administering radiation to cancer cells. Radiation therapists should have a bachelor's degrees in radiation therapy.

The radiation therapist is responsible for monitoring the condition of the patient and is required to assess if changes to the treatment plan are required. The radiation therapist is responsible for quality assurance of the radiation treatment. This involves acquiring and recording all parameters needed to deliver the treatment accurately. The radiation therapist ensures that the treatment set-up is correctly administered. The radiation therapist takes imaging studies of the targeted treatment area and reproduces the patient positioning and plan parameters daily.The radiation therapist is responsible for the accuracy of the treatment and uses his/her judgment to ensure quality with regard to all aspects of treatment delivery.

Students in radiation therapy programs learn about treatment methods for cancer patients using x-rays and other technology. Students learn to calculate doses and operate equipment in a safe manner. They typically gain hands-on experience with the machinery used in radiation therapy through an internship in a healthcare facility. This major involves a strong understanding of science, mathematics and psychology. Students are trained to work directly with patients, which includes learning to evaluate a treatment plan's success, and to communicate effectively with patients and medical staff.

Students in radiation therapy programs take a combination of lecture-based and experience-based courses, such as those in the following topics:

·         Radiation oncology

·         Basic dosimetry

·         Quality assurance

·         Ethical issues in radiation therapy

·         Radiation physics

·         Sectional anatomy

·         Safety in radiation therapy

Finally; Radiation therapists should have good communication and organization skills in order to interact with patients and work successfully with radiation oncologists, technicians and other medical professionals. They must be able to perform medical imaging procedures, including x-rays and CT scans. Because they are often standing for long hours, radiation therapists should be in good physical health.  

Proton Therapy

A proton is a positively charged particle that is part of an atom, the basic unit of all chemical elements, such as hydrogen or oxygen.

Protons are a superior form of radiation therapy. Fundamentally, all tissues are made up of molecules with atoms as their building blocks. In the center of every atom is the nucleus. Orbiting the nucleus of the atom are negatively charged electrons.

When energized charged particles, such as protons or other forms of radiation, pass near orbiting electrons,

The positive charge of the protons attracts the negatively charged electrons, pulling them out of their orbits. This is called ionization; it changes the characteristics of the atom and consequentially the character of the molecule within which the atom resides. Because of ionization, the radiation damages molecules within the cells, especially the DNA or genetic material. Damaging the DNA destroys specific cell functions, particularly the ability to divide or proliferate. 

Cancerous cells are particularly vulnerable to attacks on DNA because of their high rate of division and their reduced abilities to repair DNA damage.

Proton therapy is particularly useful for treating cancer in children because it lessens the chance of harming healthy, developing tissue. Children may receive proton therapy for rare cancers of the central nervous system (brain and spinal cord) and the eye, such as retinoblastoma and orbital rhabdomyosarcoma.

As with other forms of external beam therapy, proton beam therapy requires a treatment team, including a radiation oncologist, radiation physicist, dosimetrist, radiation therapist, and nurse. The radiation oncologist is a specially trained physician who evaluates the patient and determines the appropriate therapy, specific area for treatment, and radiation dose. Working together, the radiation oncologist, radiation physicist, dosimetrist and radiation therapist establish the best way to deliver the prescribed dose. The radiation physicist and the dosimetrist make detailed treatment calculations to ensure treatment will be accurately delivered. Radiation therapists are specially trained technologists who perform the daily radiation treatments. Radiation therapy nurses are team members who tend to your day-to-day concerns and help to manage the side effects of the treatment.

Compared with standard radiation treatment such as x-ray, proton therapy has several benefits. It reduces the risk of radiation damage to healthy tissues; may allow a higher radiation dose to be directed at some types of tumors, which may keep the tumor from growing or spreading; and may result in fewer and less severe side effects (such as low blood counts, fatigue, and nausea) during and after treatment. However, Proton therapy costs more than conventional radiation therapy, and insurance providers have varying rules about which diagnoses are covered and how much patients need to pay. 

Comparison of proton therapy with X-ray therapy

                                       photo source:http://www.shi.co.jp/quantum/eng/product/proton/proton.html

Radiation detectors for medical applications

Radiation detectors are the Instruments that can identify the presence of radiation (in the environment, on the surface of people, inside people, and Received by people as exposure).

We use radiation detectors to know where radiation energy came from and how many / how much it is.

 There are two basic types of instruments used for radiation detection:

1.   Particle counting instruments (Gas Filled Detectors, Solid and Liquid Scintillation Detectors).

2.   Dose measuring instruments (Pocket dosimeters, film badges, and personal thermo luminescent dosimeters).

The particle counting instruments are measuring the number of particles (electrons, alphas, protons, neutrons, etc.) or photons that give a signal in the detector, and give the result in counts per minute (cpm) or counts per second (cps).

The dose measuring instruments are also measuring the number of particles or photons, but the result is given in units of dose (R, Gy, Sv, etc.), or dose rate (R/s, mSv/h, Gy/min, etc.).

 Some types of commonly used detectors:

Geiger counter: The detector most common to the public is the Geiger-Mueller counter, commonly called the Geiger counter. It uses a gas-filled tube with a central wire at high voltage to collect the ionization produced by incident radiation. It can detect alpha, beta, and gamma radiation although it cannot distinguish between them. Because of this and other limitations, it is best used for demonstrations or for radiation environments where only a rough estimate of the amount of radioactivity is needed.

Geiger counter in use (Photo credit: Wikipedia)

Scintillation detectors: Scintillators are usually solids (although liquids or gases can be used) that give off light when radiation interacts with them. The light is converted to electrical pulses that are processed by electronics and computers. Examples are sodium iodide (NaI) and bismuth germanate (BGO). These materials are used for radiation monitoring, in research, and in medical imaging equipment.

Solid state X-ray and gamma-ray detectors: Silicon and germanium detectors, cooled to temperatures slightly above that of liquid nitrogen (77 K), are used for precise measurements of X-ray and gamma-ray energies and intensities. Silicon detectors are good for X-rays up to about 20 keV in energy. Germanium detectors can be used to measure energy over the range of >10 keV to a few MeV. Such detectors have applications in environmental radiation and trace element measurements. Germanium gamma ray detectors play the central role in nuclear high-spin physics, where gamma rays are used to measure the rotation of nuclei

Personal Thermo luminescent dosimeter (TLD): A small radiation monitoring device worn by persons entering environments that may contain radiation. It uses lithium fluoride crystals to record radiation exposure, not sensitive to heat and humidity and Available for use on torso and finger.

Measuring radiation inside people:

  The main paths for internal irradiation of those working with radioactive materials are inhalation and ingestion.

There are two internal dosimetry programs have been developed for measuring internal irradiation of personnel:

1.   Iodine measurement: I-131 is gamma emitters. Therefore, a gamma detector can be used to measure the iodine content of the person's thyroid. Proper calibration of the instrument is done using 'phantoms' that mimic human body composition. After gathering information about thyroid activity (in Bq) and the moment of iodine usage, we can estimate iodine uptake and intake. Since the level of radioiodine in the thyroid decreases after 5 days, the measurement must be done between 1 and 4 days after usage. The amount of radioiodine in the thyroid is compared with the annual limit on intake (ALI) and the dose received by the contaminated person can be estimated.  

2.   Urinalysis: most of the radionuclides tend to be eliminated in body fluids. By measuring activity content in urine, we can estimate the uptake and the intake. The dose is estimated by comparing the intake with the (ALI) for that particular radionuclide. 

Radioactive iodine therapy

Radioactive iodine also called radio iodine is an important radioisotopes of iodine discovered in 1938.It has a radioactive decay half-life of about eight days.

There are two radioactive isotopes that are commonly used in patients with thyroid diseases: I-123 (harmless to thyroid cells) and I-131 (destroys thyroid cells).

Radioactive iodine is associated with nuclear energy, medical diagnostic and treatment procedures, and natural gas production. It also plays a major role as a thyroid gland therapy because Iodine in food is absorbed by the body and preferentially concentrated in the thyroid where it is needed for the functioning of that gland.

Radioactive iodine, given in a capsule or liquid form, is absorbed and concentrated by the thyroid gland. 

While radiation can cause thyroid cancer, treatment of hyperthyroidism with radioactive iodine does not increase your chances of getting thyroid cancer, because the radioactive iodine passes out of your body in your urine and saliva within days depending on the dose you received and your age.

 Most people don't feel different after treatment. But a few people may feel a little nauseated.

Radioactive iodine therapy destroys any remaining thyroid tissue or cancer cells that were not removed during surgery.

Persons take radioactive iodine, must follow doctor's instructions to avoid exposing other people to radioactivity. The amount of radiation exposure markedly decreases as the distance from the patient increases. Patients who need to travel in the days after radioactive iodine (I-131) treatment are advised to carry a letter of explanation from their physician. This is because radiation detection devices used at airports or in federal buildings may pick up even very small radiation levels. Details should be discussed with a physician prior to, and at the time of, the radioactive iodine treatment.

A common treatment method for preventing iodine-131 exposure is by saturating the thyroid with regular, non-radioactive iodine-127, as an iodide salt.

The thyroid will absorb very little of the radioactive iodine-131 after it is saturated with non-radioactive iodide, thereby avoiding the radiation from radioiodine.

Side effects of radioactive iodine;

·        Dry mouth sometimes occurs.

·        Tenderness in your neck area.

·        Temporary or permanent decreases in blood cell counts.

·        Fatigue.

·        Sore throat.

·        Swelling and tenderness of the salivary glands.

·        Taste changes.

Radioactive iodine is safe to use in individuals who have had allergic reactions to seafood or X-ray contrast agents, since the reaction is to the compound containing iodine, not the iodine itself.

Most doctors also recommend that the patient follow a low iodine diet for 1 or 2 weeks before treatment. This means avoiding foods that contain iodized salt and red dye #3, as well as dairy products, eggs, seafood, and soy.

( Scheme of the thyroid gland. (Photo credit: Wikipedia)

Radiation Therapy Side Effects

There are many types of cancer treatment; the most effective type is radiation therapy.
All types of cancer treatments may cause side effects, also radiation therapy.
Radiation therapy side effects vary from person to person due to:

1. The type and location of cancer.

2. The person's health.

3. The treatment dose.

4. Other medicines the person is taking during radiation therapy such as;
      * vitamin or mineral supplements.
      * Herbal remedies and other natural health products.
      * Prescription and over-the-counter drugs, including creams and ointments.

For some persons, there are few or no radiation therapy side effects. For others, the radiation therapy side effects are more severe if they also receive chemotherapy before, during, or after their radiation therapy.

Radiation therapy side effects occur because the high doses of radiation used to destroy cancer cells can also damage healthy cells and tissues located near the treatment area. Your health care team will work with you to ease or prevent many of these radiation therapy side effects.
Most radiation therapy side effects go away within 2 months of finishing treatment. However, some radiation therapy side effects may continue after treatment is over because it takes time for healthy cells to recover from the effects of radiation therapy.

Common radiation therapy side effects:

1.The first radiation therapy side effects is Fatigue.  Fatigue associated with radiation therapy is different from fatigue from lack of sleep; it is a feeling of exhaustion that does not improve with rest. Your level of fatigue may depend on whether you are undergoing other treatments, such as chemotherapy. Fatigue usually occurs during or after the second week of radiation therapy. Symptoms of fatigue may increase or become more severe over the course of treatment. Fatigue usually goes away gradually after treatment has ended, but some people continue to feel tired for several weeks or months after radiation therapy.

2. The second radiation therapy side effects are skin problems, such as dryness, itching, blistering, or peeling. These issues usually resolve a few weeks after treatment has finished. If skin damage from radiation treatment becomes a serious problem, the doctor may change the dose or schedule of treatments.

3. The third radiation therapy side effects are Hair loss which can begin about 2–3 weeks after radiation therapy starts. Smaller doses of radiation usually result in temporary hair loss. Permanent hair loss is more common at higher doses.