EFEK BIOLOGI PADA PEMERIKSAAN MRI

Medan magnet, dalam ilmu Fisika, adalah suatu medan yang dibentuk dengan menggerakan muatan listrik (arus listrik) yang menyebabkan munculnya gaya di muatan listrik yang bergerak lainnya. (Putaran mekanika kuantum dari satu partikel membentuk medan magnet dan putaran itu dipengaruhi oleh dirinya sendiri seperti arus listrik; inilah yang menyebabkan medan magnet dari ferromagnet "permanen"). Sebuah medan magnet adalah medan vektor: yaitu berhubungan dengan setiap titik dalam ruang vektor yang dapat berubah menurut waktu. Arah dari medan ini adalah seimbang dengan arah jarum kompas yang diletakkan di dalam medan tersebut.

EFEK BIOLOGI :

- medan magnet bumi tidak memberi dampak pada kehidupan makhluk kecil

  Mis: burung migrasi terkena 6 gauss.

- penelitian pd monyet dengan 10 T magnet tidak ada efek yg membahayakan.

- hasil penelitian penggunaan magnet < 2 T tidak ada efek pd pertumbuhan atau morfologi sel

SEBELUM KITA BICARA LEBIH LANJUT TENTANG DAMPAK MRI KITA BELAJAR DULU BARANG2 APA SAJA YANG TIDAK BOLEH MASUK MRI

1.Jam analog

2.Tape recorder

3.Credit card

4.Calculators

5.Perhiasan

6.Wigs

7.Jepit rambut

8.Gigi palsu dll

9.Pasien dengan pacemaker

10.Pasien dengan klip aneurisme

Bahan ferromagnetik dpt berbahaya

1.Bahan feromagnetik semua tertarik oleh magnet. Klip kertas atau hair pins – bila tertarik ke magnet (1,5 T) kecepatan hingga 60 km/jam.

2.Alat bantu lain : hemostats, gunting, klem yg terbuat dari stainless steel juga tertarik magnet

3.Tangki oksigen juga dpt ditarik oleh magnet

4.Petugas lain spt perawat, cleaning service, pemadam kebakaran dll harus diberi penjelasan tentang bahaya magnet tsb.

5.Di depan ruangan, harus ditempelkan tanda

6.Masyarakat umum harus berada di area 5-15 G

7.Screening dengan metal detector bila ada.

EFEK JIKA MEMAKAI BARANG-BARANG SEPERTI DIATAS

• Implantasi pd pasien dapat menimbulkan serius efek spt : torque (berputar), heating, artifact pd gbr MRI.

 

• Aneurisme klips : kontra indikasi MRI .Hanya akan diperiksa dengan MRI bila klips tsb pasti non ferromagnetic.
• Protehese : pd katup jantung : dr penelitian diketahui bahwa 25 dr 29 prothesis terpengaruh oleh magnet, akan tetapi pergerakannya masih lebih kecil dibanding dgn akibat pergerakan jantung. Model Pre-6000 kontra indikasi MRI.

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MEDIA KONTRAS MRI

•Contras media MRI peningkatan pencitraan yg diperoleh dari absorpsi gelombang radio oleh inti atom

•Contras media MRI adalah bahan paramagnetic atau superparamagnetic yg meningkatkan citra resonansi magnetic dengan mempengaruhi waktu relaksasi dari inti

•Media kontras paramagnetic meliputi kompleks gadolinium seperti gadodiamid, gadopentetic acid dan gadoteridol dan kompleks mangan

•Superparamagnetic meliputi Kompels iron, ferrocarbitrans dan ferromoksil

Indikasi pemberian kontras pada MRI :

1.MRI Brain

Indikasi :

•Neoplasia

•Infection

Infarction

2.MRI Spine

Indikasi :

•Degenerative disc disease

•Inflamatory lesions

•Neoplasia

•Vascular disease

•Demyelination

•Conginetal lesions

3.MRI Whole Body

Indikasi :

•Bronchogenic carcinoma

•Acute myocardial infarction

•Breast imaging

•Liver and spleen

•Bowel

•Kidney

•Adrenal gland

•Pelvis

•Musculoskeletal system

KONTRA INDIKASI Untuk Pemeriksaan MRI

•Mutlak :

–kehamilan dan menyusui

–Gagal ginjal

•Relatif :

–Anemia hemolitika

–Riwayat reaksi alergi dengan bahan iodida

TYPE MEDIA KONTRAS MRI

•Intravenous

–Extracelluler distribution

•Gd DTPA (Gadopentetate dimeglumin)

•Gd HP-DOGA (Gadoteridol)

•Gd DTPA-BMA (Gadodiamide)

•Gd DCTA

–Hepatobillary

–Particulate

•Oral

–Metal chelat

•GD DTPA

–Magnetic Iron Oxide Particles

•Oral Magnetic Particles

•AMI-121

7T MRI* Explore the Future of MRI. Today.

Siemens is the world leader in MRI technology and applications development. With more and more applications calling for higher resolution images, ultra-high-field MRI technology has become compulsory for leading institutions. 3T MRI has become clinical reality in order to answer complicated questions and to leverage the transfer of research methods into useful clinical applications. 7T MRI* now emerges as the equipment of the elite, the new research and development frontier, the system of the pioneers.

7T MRI - a great research instrument

7T MRI provides the potential for microscopic spatial resolution visualizing anatomy previously unseen. In addition, it enables the observation and analysis of tissue metabolism and function. 7T MRI is a great instrument for the research and development of molecular imaging methods, promising a whole new world of applications. High-level MR hardware and software expertise on site are prerequisites for the successful operation of such a system. 7T MRI systems are investigational devices and are not available for clinical use (i.e. it can not be used for clinical diagnosis but only for clinical research purposes).

7T MRI brings certain types of MRI research, such as ultra-high resolution human fMRI (0.1mm resolution, which reach slowly the level of resolution provided by histology), out of the animal realm for the first time. It will eventually become possible to study neuronal function at the sub-millimeter scale. Potential clinical applications include neurodegenerative diseases (Alzheimer, etc.). The focus is currently set on brain imaging but other applications in the rest of the body are not excluded.

The Siemens 7T MRI program includes today:

• 7T Head Scanner: 90 cm bore size magnet. Actively shielded 2.20 m long magnet with 68 cm bore diameter, enables siting of 7T in a conventional 3T foot print.
• 7T Whole-Body Scanner: Unshielded 90 cm bore size magnet witch is 3.40 m long.

Siemens 7T MRI projects

Siemens Healthcare is the leading vendor in 7T ultra-high-field MRI. More than half of the 30 installed systems worldwide are from Siemens. The success of the Siemens ultra-high-field program is explained by the technological leadership provided by Siemens and in particular: the 32 independent RF channels of the Tim technology, the strong, fast and reliable gradients as well as the most advanced application methods. The success is also explained by the strong collaboration between the research institutes hosting the 7T systems and Siemens, which is not only necessary but a prerequisite for full exploitation of the capabilities of such a system.

Siemens collaboration with the CEA

The Commissariat à l’Energie Atomique (CEA) with headquarters in Paris and Siemens Healthcare agreed to expand and intensify their joint research activities in the area of innovative imaging and therapy. This included the area of ultra-high-field MRI, the development of 11.7 T systems for human applications as well as 17 Tesla systems for small animal research should lead to breakthroughs in the areas of diagnosis and therapy for neurological diseases, such as Alzheimer’s or Parkinson’s disease. At present, the upper limit for human applications is 7 Tesla.
"Siemens is the ideal partner for us to transfer our comprehensive know-how and long-term experience in the area of medical imaging, diagnostics and therapy from research to clinical routine," says Alain Bugat, Administrateur Général of CEA. “There is no doubt in my mind that as a team we are able to move medicine a giant step forward.“