DIAGNOSTIC RADIOLOGY AND RADIOTHERAPY METHODS. Care and safety information for CANCER patientS

During a lifetime every person undergoes dozens of radiological procedures (X-ray, fluorography, computed tomography) used for diagnostics of various disease. So these types of ionizing radiation are usually comprehensible and out of question.

However, in case of cancer, numerous radiotherapy sessions can be prescribed for the patient in a short span of time. Radiotherapy is a narrow-focused branch of medicine, therefore it remains a puzzle for nonexperts. We tried to imagine what issues might be of concern to a person who is waiting for radiological diagnostics or radiotherapy and collected information on each of these issues.

 Radiologists Oleksiy Galchenko (Bogomolets National Medical University) and Maryna Satyr (Heart Institute of the Ministry of Health of Ukraine) were very helpful for us.

 

What methods of diagnostic radiology and radiotherapy are used for cancer? 

Diagnostic radiology is a type of treatment which is based on the insertion of radiopharmaceuticals — pharmaceutical compounds consisting of radioisotopes linked to organic transport molecules — into the human body. Radioisotopes act as markers accumulating in tissues or organs which concentration is detected by the equipment. This allows to visualize the presence or absence of malignancies, their exact location and extent.

Also, radiopharmaceuticals can be used for treatment of a number of benign and malignant tumors, thyroid, musculoskeletal and neuroendocrine system disorders (radiotherapy or systemic radiation therapy (molecular therapy)). This type of therapy is prescribed in case of multiple locations of the disease. Radiotherapy is based on the local effect of the radioisotope, accumulated in the tissue or organ during metabolism, on the tumor.

Read more about the use of radiopharmaceuticals (nuclear medicine)

If radiation is delivered to the patient from external source, it is called radiotherapy which can be of two types: remote radiotherapy (dose is delivered to the patient using the ionizing radiation source (IRS) arranged inside the equipment) and contact radiotherapy or brachytherapy (closed IRS implanted directly into the tumor usually through the natural body cavities). More often radiotherapy is used in case of single location of the disease which can be clearly separated and irradiated.

More information about radiotherapy options, functional concept and equipment

Each of radiotherapy methods is most effective for certain diseases and tumors, so the choice of a method depends on the diagnosis and treatment strategy recommended by the doctor.

How often the radionuclides are used for cancer detection?

Radiotherapy is a valuable diagnostic and prognostic method for certain health disorders, first of all for hormone-dependent tumors. The results of these studies are important for specification of the disease state and subsequent treatment strategy. Therefore, in case of prostate and breast cancer this method is very informative and effective.

At what age a patient can start radiotherapy?

You can start radiotherapy at any age since we talk about treatment of aggressive disease. In this case, method effectiveness outweighs the side effect which is unfortunately present.

What is the radiotherapy procedure?

Usually remote radiotherapy course takes 6-11 weeks. The total dose is divided into fractions (most often it is 2 Gy fractions) delivered to the patient five days a week. Due to this, normal tissues affected by radiation have time for regeneration between treatment sessions. However, there are radiotherapy methods which envisage daily delivery of several fractions to the patient.

First, the patient attends simulation session, that is, treatment planning session. The patient is positioned on the treatment table exactly in that position which he shall take during radiotherapy sessions. After that, radiation technician, using any of radiologic imaging methods, takes a picture of that part of the patient’s body where the tumor is located. After receiving of the image and results of other analyses, the doctor draws up a radiation plan, where he prescribes in detail the dose, number and form of radiation beams and number of therapy sessions.

At radiotherapy sessions the patient’s skin gets special markings or marking particles are implanted into the tumor for precise targeting of radiation beam. Sometimes human body is fixed so that changes in body position not to result in radiation beam displacement against the target. During session the patient is alone in therapy room, however, the radiotherapist, who controls the equipment from adjacent room, keeps visual and verbal contact with the patient. One treatment session usually lasts for 10-20 minutes.

Patients undergo systemic radiation therapy in separate departments of oncology clinics. Medication by high dose radiopharmaceuticals requires special conditions for patient management and observation.

What radiation doses does the patient receive? Are they dangerous for other organs?

In case of radiotherapy we do not consider radiation exposure to all organs of the patient but maximal dose delivering to a tumor with minimal radiation exposure to healthy and especially to the vital organs.

The total dose to the primary tumor site makes, as a rule, 60-75 Gy, to the metastasis area – 45-50 Gy.

In case of radiotherapy the patient can take high dose radiopharmaceuticals (3500 MBq for iodine-131, up to 500 MBq for strontium-89, 200 MBq for gold-198).

Diagnostic radiopharmaceuticals contain naturally excreted radionuclides with a short half-life (from a few minutes (sometimes even seconds) to several hours, sometimes — days). Therefore, the committed radiation dose is not harmful for the human body.

What are the side effects of radiotherapy?

Radiotherapy is painless since the patient does not feel negative effect of radiation. However, repeated delivery of ionizing radiation to the human body can result in certain adverse reactions.

First of all, we consider the skin reaction since the skin is a dose “gateway”. These reactions are minimized by delivering the dose exactly to the tumor. The dose is delivered from different sides for not to exceed the maximum permissible dose for each skin area.

The alopecia does not take place during the radiotherapy — such effect is typical for the chemotherapy.

As for the general somatic effects (radiation consequences for the body cells) — it all depends on the tumor volume, location, general state of the patient and therapy course.

Local reactions to radiation can occur due to irradiation of vital organs and tissues. The majority of these reactions disappear in 2-3 weeks without any special treatment. Radiotherapy causes radiation injury, that is, organic and functional changes in organs and tissues that require special treatment. Radiation injuries are classified as follows: early radiation injuries (occur in the process of radiotherapy or within subsequent three months) and delayed radiation injuries (after six months, year and a half and more). Delayed radiation complications undergo comprehensive treatment using local and general medication.

It is necessary to point out that in compliance with medical data there were no study cases of patient’s death due to delayed radiation complications. In any case, all possible side effects should be discussed individually with your doctor.

Is the patient radioactive during the radiotherapy course? Are there any restrictions on communication with other people during treatment?

If we talk about remote radiotherapy, the answer is — no. The dose is delivered from the outside with the help of specially designed equipment.

Is it possible to wear clothes and things used by the patient during radiotherapy? Can they be contaminated?

There are no restrictions on wearing clothes during remote radiotherapy course. After receiving certain radiation fraction the patient can go home — his things are of no danger to others.

In case of medication by radiopharmaceuticals, patient’s personals and clothes are stored in clinic storage room until radioactivity level is decreased and then returned to the patient.

Is it necessary to follow special diet during radiotherapy?

No, it is not necessary if the treatment does not cause individual gastrointestinal reactions. In this case, you need to consult a doctor.

Are there any paternity (maternity) risks for patients who underwent the radiotherapy?

Usually there are no risks. The risk can occur if the tumor has affected the reproductive system and the gonads (reproductive glands) and when these organs underwent radiation exposure.

Are there any contraindications for pregnancy and breast feeding?

During pregnancy, any therapy with the help of ionizing radiation is contraindicated. As for the breast feeding, there are no such restrictions.

As for diagnostic radiology and radiotherapy, breastfeeding should be stopped for the whole radiotherapy period and continued after the excretion of radiopharmaceuticals.

Are any dental crowns, titanium plates, cardiac pacemakers, transplanted organs contraindicated for radiotherapy?

A passport is issued for each implant. It contains implant specifications and usage recommendation. Implants are not contraindicated for radiotherapy, but one should consider their presence in radiation area since they effect dose distribution. Dental crowns are not contraindicated for radiotherapy or diagnostic radiology in any way.

Transplanted organs are also not a contraindication to radiotherapy and nuclear medicine. However, the doctor should be informed about the medication taken by the patient after the transplantation for him to take this into account when drawing up the treatment plan.

It is special situation with cardio pacemakers. It is important to consult a cardiologist about cardio pacemakers. Usually, they are not contraindicated.

What are the alternative cancer treatment methods other than radiotherapy?

There are approved mandatory protocols for treatment of various cancers which include surgery, medication (chemotherapy) and radiotherapy. All methods complement each other. If the doctor whom you trust considers that radiotherapy is the most effective method for treatment of certain health disorders then you should choose this method.

We appreciate the help of radiologists Oleksiy Galchenko (Bogomolets National Medical University) and Maryna Satyr (Heart Institute of the Ministry of Health of Ukraine).