Debbi Kamel, Witmeyer Sarah, Bennassi Alexander, Boukhobza Chahrazed, Fonteneau Gloria, To Nhu Hanh, Coraggio Gabriele, Ksouri Wassim, Grellier Noémie, Cherif Mohamed Aziz, Loganadane Gokoulakrichenane, Belkacemi Yazid
Department of Radiation Oncology, Henri Mondor Breast Center, Henri Mondor University Hospital, AP-HP, University of Paris Est Creteil (UPEC), Créteil, France.
Institut Mondor de Recherche Biomédicale (IMRB), INSERM U955, i-Biot, UPEC, Créteil, France.
Adv Radiat Oncol. 2025 May 16;10(7):101808. doi: 10.1016/j.adro.2025.101808. eCollection 2025 Jul.
To determine the benefit/risk in terms of radioprotection of performing a mini-computed tomography (CT) scan prior to the planning CT scan in patients requiring pelvic irradiation. The study population included patients who received curative intent external beam radiation therapy for pelvic malignancies. The results are applicable to all supine pelvic external beam radiation therapy patients.
Between April 9, 2021, and October 5, 2021, 53 patients were included in the study. A mini-CT scan was performed for each patient to determine whether they were properly prepared with a full bladder and empty rectum for the planning CT scan. Depending on the result, it was decided to either perform the planning CT scan or repeat a mini scan after rectal enema and drinking to better empty the rectum and fill the bladder. Up to 3 mini scans could be performed, after which a new CT appointment was scheduled if the patient was considered not sufficiently prepared.
Among the 53 patients included in the study, 64 wide CT scans were performed (average, 1.2 scans per patient). A total of 47, 3, 2, and 1 patients were treated for prostate, rectal, bladder, and anal canal cancers, respectively. The median age was 75 years (range, 57-94), with 51 men and 2 women. For 29 patients, a single mini-CT scan was performed prior to the wide CT scan, corresponding to an additional mean effective dose of 2.3 mSv to the mini-CT scan. For 25 patients, multiple wide CT scans and mini-CT scans were performed. For these patients, the mini-CT scan allowed us to decrease patient exposure by reducing the average effective dose by 22.1 mSv per patient. The systematic use of a mini-CT scan in the whole cohort allowed reducing the mean effective dose by 9.44 mSv based on a paired test ( < .0001).
We demonstrated that the effective dose delivered to the patient was significantly lower if we carried out 1 or more mini-CT scans to avoid doing iterative planning CT scans that deliver a higher dose to the patient.
确定在需要盆腔放疗的患者中，在计划CT扫描前进行微型计算机断层扫描（CT）对辐射防护的益处/风险。研究人群包括接受盆腔恶性肿瘤根治性外照射放疗的患者。研究结果适用于所有仰卧位盆腔外照射放疗患者。
在2021年4月9日至2021年10月5日期间，53名患者纳入研究。为每位患者进行一次微型CT扫描，以确定他们是否为计划CT扫描做好了膀胱充盈和直肠排空的准备。根据结果，决定是进行计划CT扫描，还是在直肠灌肠和饮水后重复进行微型扫描，以更好地排空直肠和充盈膀胱。最多可进行3次微型扫描，如果患者被认为准备不充分，则安排新的CT检查预约。
在纳入研究的53名患者中，共进行了64次全尺寸CT扫描（平均每位患者1.2次扫描）。分别有47、3、2和1名患者接受了前列腺癌、直肠癌、膀胱癌和肛管癌的治疗。中位年龄为75岁（范围57 - 94岁），其中男性51名，女性2名。29名患者在全尺寸CT扫描前进行了一次微型CT扫描，微型CT扫描的额外平均有效剂量为2.3 mSv。25名患者进行了多次全尺寸CT扫描和微型CT扫描。对于这些患者，微型CT扫描使我们能够将每位患者的平均有效剂量降低22.1 mSv。在整个队列中系统使用微型CT扫描，基于配对检验，平均有效剂量降低了9.44 mSv（P <.0001）。
我们证明，如果进行1次或更多次微型CT扫描以避免进行向患者传递更高剂量的迭代计划CT扫描，传递给患者的有效剂量会显著降低。
