In this study, 5 subjects will be enrolled and the cumulative D2cc dose for rectum during brachytherapy will be recorded as the primary outcome measures.

This is a phase I prospective study of 5 patients to determine if PEG hydrogel (ReSpace™) reduces the radiation dose delivered to the rectum during radiation therapy for cervical cancer by increasing the space between the cervix and the anterior rectal wall. In the other word, the purpose of this study is to assess whether the use of ReSpace™ hydrogel results in a reduction of radiation exposure to the anterior rectum.

Inclusion Criteria:

• Patients with pathologically confirmed cervical cancer who must be scheduled to undergo radical radiotherapy by means of intensity-modulated radiotherapy combined with 3D brachytherapy.
• Karnofsky score ≥ 70.
• Subjects aged ≥ 18 years and ≤ 75 years.
• Subjects must be able to cooperate in completing the entire study.
• The subjects' pelvic and abdominal cavity and joints are free of metal implants and can tolerate MRI.
• No contraindications to CT scanning.
• Subjects must be able to understand the purpose of the trial, voluntarily participate and sign an informed consent form.

Exclusion Criteria:

• Subjects who have received prior pelvic radiotherapy.
• Subjects whose target tumors have been previously treated (chemotherapy, immunotherapy, surgical treatment, etc.)
• Subjects with other primary malignancies
• Subjects with contraindications to radiotherapy, as determined by the investigators
• Subjects with injection site infections.
• Subjects who are allergic to the ingredients of the device.
• Subjects whose tumors invade the injection site and affect the injection process and injection safety, as determined by the investigators
• Persons with severe mental illness, cognitive impairment and thinking disorders.
• Participants in other drug clinical trials or medical device clinical trials 1 month prior to screening
• Pregnant or lactating women or those who plan to get pregnant within the last six months
• Subjects who cannot be followed up as prescribed by the doctor
• Other conditions that, in the judgment of the investigator, make the subject unsuitable for enrollment