ПЭТ-КТ исследования

This modern nuclear medicine technique combines positron emission tomography (PET) with computed tomography (CT), an X-ray examination that allows for the highest level of detail. This procedure is used primarily to diagnose and stage tumors such as lung cancer. This method can also answer cardiac and neurological questions, for example in dementia. In addition, gallium-PSMA is a new substance for patients with prostate cancer.

PET/CT

What it is?

PET/CT is a test that can be used to visualize the main metabolic processes in the body.

Для этого вам вводят меченную радиоизотопом глюкозу (18FDG), которая накапливается в организме в зависимости от метаболизма отдельных клеток. Естественно, 18FDG накапливается в сердце и мозге, но метаболически активные опухолевые клетки и воспалительные ткани поглощают 18FDG в большей степени. Примерно через час после введения 18FDG делаются ПЭТ/КТ-снимки для оценки метаболизма и КТ-снимки для анатомической классификации.

The examination itself takes about 15 minutes. After the examination, the attending physician examines the images and, depending on the question asked, provides you with the initial result.

When is PET/CT used?

PET/CT with radiolabeled glucose is a common procedure for various tumor diseases (lung cancer, ENT tumors, lymphomas, liver metastases from intestinal tumors, esophageal tumors and many other diseases).

How is the examination carried out?

Before the study, you will have an informative conversation with your doctor, during which you will be able to discuss any questions that interest you. We will then determine the final indications and decide whether PET/CT will be performed in conjunction with low-dose CT (if a diagnostic CT has already been performed in the recent past) or whether an additional diagnostic CT study will be required.

The next step is the introduction of 18FDG (radiolabeled glucose)

About an hour after the 18FDG injection, the machine produces PET/CT images, as well as low-dose or diagnostic CT, depending on the history of the disease and the nature of the tumor.

For some types of tumors, during the examination we also record the breathing process using a special chest strap, this makes it possible to calculate the possible displacement of individual focal formations during breathing in the images.

Sometimes, immediately after the first study, additional images are taken on a special platform, in cases where the data obtained are necessary for planning subsequent radiation therapy.

18F-PSMA PET/CT

What is 18F-PSMA PET/CT?

PSMA PET/CT is used to visualize the distribution of prostate specific membrane antigen (PSMA) in the body. Prostate specific membrane antigen accumulates in prostate tumor cells and also accumulates naturally in the salivary glands, liver and spleen, kidneys and intestines.

What is 18F-PSMA PET/CT used for?

PSMA PET/CT examination is usually used for the initial diagnosis of prostate carcinoma, before a course of therapy or in the case of biochemical recurrence of prostate cancer.

In more rare cases, PSMA PET/CT is also used to study late stages of prostate cancer when there is metastasis. PSMA expression in these metastases is so high that PSMA-targeted therapy, such as the use of 177Lu-PSMA, may be promising.

Who is conducting it? 18F-PSMA PET/CT?

1. Patients with no decline in PSA levels below 0.2 ng/mL within 3 months after radical prostatectomy for localized prostate carcinoma.
2. Patients with PSA relapse after radical prostatectomy (PSA value > 0.2 ng/mL confirmed by two measurements) or after radiation therapy alone (PSA increase > 2 ng/mL confirmed by two measurements) of localized prostate carcinoma.

In cases 1. and 2., if the PSA value is > 10 ng/ml, to localize the tumor, it is necessary to first carry out routine examinations, including pelvic MRI and skeletal scintigraphy.

3. Patients with high-risk prostate cancer (Gleason score 8-10, tumor size cT3/cT4 or PSA ≥ 20 ng/ml) to diagnose disease spread before therapy (with 18F-FDG and PSMA ligands).
4. In patients with castration-resistant prostate cancer and with advanced disease to determine indications for therapy using 177Lu-PSMA

How does 18F-PSMA PET/CT study work?

At the beginning of the study, the patient is injected with radioactively labeled PSMA (18F-PSMA 1007) - more correctly called the PSMA ligand - which accumulates on tumor cells depending on the level of PSMA expression. Prostate specific membrane antigen naturally accumulates in the salivary glands, liver and spleen, kidneys and intestines, and ganglia also sometimes absorb PSMA to an increased extent. Approximately 100 minutes after administration of 18F-PSMA, PET/CT images are taken and CT images are taken for anatomical identification.

The examination itself takes about 20 minutes. Your doctor will then evaluate the images and tell you the results.