Have you heard about Brachytherapy before? And How can a phyisicist like me talk about it?
Ok no problem, so I will explain how can radioactive cure the cancer patient, after that I will tell about the brachytherapy method, the physical and medical aspect for this treatment, and how make a treatment planning system
Cancer is the most diseases caused human die. From World Healthy Organization (WHO) The number of cancer patient in the world increased every year. at two thousand and eight there are more than seven million people deaths and 2 of 3 patients is from developed country.
Cancer patients can get cured by a lot of method. There are surgery, chemotherapy, nuclear medicine, or radiotherapy. Radiotherapy is one of treatment which use radioactive particle to kill the tissue of cancer. Radioactive element emit particle like alpha, beta or gamma. This particle have high energy which can destroy of DNA of cancer cell so the cancer will die and stop growing
If we talk about radioactive, it’s not only work of doctor. Scientist and engineer can make any research about it. So what can the physicist do?
Ok now we discuss about cancer therapy. When someone has indication of cancer, the patients will go to doctor called oncologist. Oncologist will make him get a imaging test like MRI, CT Scan, etc for look how dangerous the cancer. The most dangerous cancer stadium is called stadium IV, it means the cancer has spread out over the organ. The treatment for this patients will depend on the imaging test and the comfort of patient. One of the solution therapy is brachytherapy, brachytherapy is a type of internal radioactive with the source of radiation is placed directly inside or next to the tumor. The element will decay and emit the high energy particle.
Because the source of radioactive near the cancer cell, so it must have dose precisely. Brachytherapy can be more effective treatment for some case of cancer, because this method can get the target exactly and minimaiz the side effect furthermore it can make the patient recovery faster, because no more scar was made when doing treatment
There are two types of brachytherapy treatment:
– Intracavitary, this method make a source of radioactive have a shielding like capsule called sealed. For some case sealed was placed in something like balloon. It is intended for decreased the radiation effect to healthy cell
– Interstitial, source is placed near the cancer cell with use something like wire or needles.
It is a picture when radioactive seeds plan in the brain tumor with brachytherapy treatment
There is physical and medical aspect for brachytherapy sources. The radioactive source can emit by cobalt-60, cesium-137, indium-192, iodine-125, and palladium-103. It is emit alpha, beta which have a charge or gamma which have no charge. As we know this particle have some quantities, there are photon energy, half life (time required for quantity to fall of half its value as measured at the beginning of the time period, Half value layer (thickness of the material at which the intensity of radiation entering it is reduce by one half, shielding material, specific activity (quantity of particle which can emit by radioactive element), source strength. If you can see in picture example of seed for brachytherapy, the radioactive element inserted to seed, and implant to the body near the cancer cell.
And than how do we know where the seed was placed? how much radioactive was implanted? and how long was planted in the body?
The method is called Treatment Planning System, it use software to calculated the effective treatment for the patient use the parameter mentioned before. The doctor usually discussed the imaging of patient with the treating physicist. TPS is used to determine source strength, source distribution and loading patterns. Furthermore TPS can make document isodose distribution. After the doctor has analyze the image of cancer it will have a checked by Quality evaluation, quality evaluation is the parameter which has calculated before and has become an exact value and can see in the fix table calculated
It can see in the picture, some example of treatment planning system with CMS XiO software. The black side is the cancer cell, and around that with the lighter side is the healthy cell. This software calculated the dose parameter radiation which will give to the body.
Result and discussion
Brachytherapy is one of method treatment for cancer patient. It is medical Internal treatment use radioactive element which has short distance with the cancer cell target. For make the dose and method precisely, doctor should make discussion with physicist for analyze Treatment Planning System of cancer imaging to determine the right treatment for patient will use
Presentation of Scientifict Comunication Lecture