Low-Count Quantitative SPECT for Men Treated With Radium-223

N/ANot Yet RecruitingNCT07221825

Washington University School of Medicine38 enrolled

Overview

Internal radiotherapies (radiolabeled molecules that are systemically administered and localize to sites of disease) provide cancer-ablating doses to diseased cells while sparing adjacent normal tissues. \[223Ra\]RaCl2 (Xofigo) is the first FDA-approved alpha-particle emitting radiopharmaceutical therapy (αRPT), providing a survival benefit for men with bone metastatic castration-resistant prostate cancer. Systemically administered radiotherapies distribute throughout the patient, accumulating to unknown levels at sites of disease and in radiosensitive vital organs. The whole-body distribution means that absorbed doses in the patient extend far beyond a pre-defined treatment field. There is a lack of information about αRPT distribution and localization, and this confounds treatment monitoring, complicates dose and schedule personalization, and impedes drug development. Single-photon emission computed tomography (SPECT) imaging offers a mechanism to quantify uptake; however, αRPT administered activities are significantly lower than those used with diagnostic procedures, which presents a challenge for quantitation with conventional methods. Preliminary research shows that low-count quantitative SPECT (LC-QSPECT) imaging demonstrates reliable quantitation of regional uptake for αRPTs. The purpose of this study is to demonstrate the feasibility, tolerability and performance of LC-QSPECT imaging.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

DIAGNOSTIC

Masking

NONE

Enrollment

Conditions

Prostate Cancer

Outcomes

Primary Outcomes

Spearman's correlation coefficient between the LC-QSPECT estimated uptake in the lesions and intestine with ex vivo activity sampling

The investigators will assess if the correlation (in absolute magnitude) ≥ 0.60 between the tissue and SPECT data against a low correlation of \< 0.2 based on 1-sided normal test at a 5% level.

Time frame: Through collection of ex vivo sample (estimated to be 3 months)

Secondary Outcomes

LC-QSPECT related adverse events

Time frame: From start of LC-QSPECT imaging through 12 hours following LC-QSPECT imaging

Percentage of enrolled patients who withdraw from the study due to adverse events at least possibly related to LC-QSPECT (as chosen by patients or treating physician team)

Time frame: From start of LC-QSPECT imaging through 12 hours following LC-QSPECT imaging

Feasibility of conducting LC-QSPECT will be determined by percentage of SPECT scans that can be processed using the investigators' computational method

Feasibility is defined as at least 80% of scans able to be processed.

Time frame: Through completion of LC-QSPECT imaging (estimated to be 3 months)

Correlation between the LC-QSPECT measurements and PSA (Spearman Correlation Coefficient)

Spearman correlation coefficient measures the strength and direction of the linear correlation (dependence) between 2 variables after converting the raw data to ranks, giving a value between +1 and -1 inclusive, where 1 indicates perfect positive correlation, 0 indicates no correlation, and -1 indicates perfect negative correlation.