Purpose: High geometrical and dosimetrical accuracies are required for radiotherapy treatments where IMRT is applied in combination with narrow treatment margins in order to minimize dose delivery to normal tissues. As an overall check, we implemented a method for reconstruction of the actually delivered 3D dose distribution to the patient during a treatment fraction, i.e., the 'dose of the day'. In this article results on the clinical evaluation of this concept for a group of IMRT prostate cancer patients are presented.

Materials And Methods: The actual IMRT fluence maps delivered to a patient were derived from measured EPID-images acquired during treatment using a previously described iterative method. In addition, the patient geometry was obtained from in-room acquired cone-beam CT images. For dose calculation, a mapping of the Hounsfield Units from the planning CT was applied. With the fluence maps and the modified cone-beam CT the 'dose of the day' was calculated. The method was validated using phantom measurements and evaluated clinically for 10 prostate cancer patients in 4 or 5 fractions.

Results: The phantom measurements showed that the delivered dose could be reconstructed within 3%/3mm accuracy. For prostate cancer patients, the isocenter dose agreed within -0.4+/-1.0% (1 SD) with the planned value, while for on average 98.1% of the pixels within the 50% isodose surface the actually delivered dose agreed within 3% or 3mm with the planned dose. For most fractions, the dose coverage of the prostate volume was slightly deteriorated which was caused by small prostate rotations and small inaccuracies in fluence delivery. The dose that was delivered to the rectum remained within the constraints used during planning. However, for two patients a large degrading of the dose delivery was observed in two fractions. For one patient this was related to changes in rectum filling with respect to the planning CT and for the other to large intra-fraction motion during treatment delivery, resulting in mean underdosages of 16% in the prostate volume.

Conclusions: A method to accurately assess the 'dose of the day' was evaluated for prostate cancer patients treated with IMRT. To correct for observed dose deviations off-line dose-adaptive strategies will be developed.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.radonc.2010.05.015DOI Listing

Publication Analysis

Top Keywords

prostate cancer
20
cancer patients
20
'dose day'
16
dose
12
delivered dose
12
prostate
8
imrt prostate
8
dose delivery
8
fluence maps
8
phantom measurements
8

Similar Publications

Here we report results of a phase 1 multi-institutional, open-label, dose-escalation trial (NCT02744287) of BPX-601, an investigational autologous PSCA-directed GoCAR-T® cell product containing an inducible MyD88/CD40 ON-switch responsive to the activating dimerizer rimiducid, in patients with metastatic pancreatic (mPDAC) or castration-resistant prostate cancer (mCRPC). Primary objectives were to evaluate safety and tolerability and determine the recommended phase 2 dose/schedule (RP2D). Secondary objectives included the assessment of efficacy and characterization of the pharmacokinetics of rimiducid.

View Article and Find Full Text PDF

Background: In TALAPRO-2, the poly(ADP-ribose) polymerase inhibitor talazoparib plus the androgen receptor-signaling inhibitor enzalutamide improved radiographic progression-free survival (rPFS) versus placebo plus enzalutamide (hazard ratio [HR] = 0.63; 95% CI, 0.51-0.

View Article and Find Full Text PDF

Advancements in pseudouridine modifying enzyme and cancer.

Front Cell Dev Biol

December 2024

Department of Oncology, The First Affiliated Hospital, College of Clinical Medicine, Henan University of Science and Technology, Luoyang, Henan, China.

Pseudouridine (Ψ) is a post-transcriptional modifier of RNA, often referred to as the 'fifth nucleotide' owing to its regulatory role in various biological functions as well as because of its significant involvement in the pathogenesis of human cancer. In recent years, research has revealed various Ψ modifications in different RNA types, including messenger RNA, transfer RNA, ribosomal RNA, small nuclear RNA, and long noncoding RNA. Pseudouridylation can significantly alter RNA structure and thermodynamic stability, as the Ψ-adenine (A) base pair is more stable than the typical uridine (U)-A base pair is due to its structural similarity to adenine.

View Article and Find Full Text PDF

Silencing of STEAP3 suppresses cervical cancer cell proliferation and migration via JAK/STAT3 signaling pathway.

Cancer Metab

December 2024

Department of Obstetrics and Gynecology, First Affiliated Hospital, Shihezi University, Shihezi, China.

Article Synopsis
  • STEAP3 is a critical protein associated with cervical cancer (CC) progression, showing strong expression in CC tissues and linked to poor patient prognosis.
  • The study employed various methods, such as immunohistochemistry and RNA sequencing, to investigate STEAP3's role, revealing that lower methylation levels of STEAP3 are connected to worse outcomes.
  • Knockdown of STEAP3 in CC cells reduced their growth and invasion abilities while enhancing drug sensitivity, suggesting STEAP3 drives cancer cell activity through the activation of the JAK/STAT3 signaling pathway.
View Article and Find Full Text PDF

Background: To assess the clinical utility of PCA3 in the diagnostic accuracy, the correlation between PCA3 and biopsy or pathological characteristics and the performance of PCA3 to reduce the unnecessary biopsies in Chinese population.

Methods: A prospective study including patients with indication of prostate biopsies from 4 centers was conducted. All patients underwent PCA3 urine tests and prostate biopsies.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!